@article{zanno_gates_avrahami_tucker_makovicky_2023, title={An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America}, volume={18}, ISSN={["1932-6203"]}, url={https://doi.org/10.1371/journal.pone.0286042}, DOI={10.1371/journal.pone.0286042}, abstractNote={Intensifying macrovertebrate reconnaissance together with refined age-dating of mid-Cretaceous assemblages in recent decades is producing a more nuanced understanding of the impact of the Cretaceous Thermal Maximum on terrestrial ecosystems. Here we report discovery of a new early-diverging ornithopod, Iani smithi gen. et sp. nov., from the Cenomanian-age lower Mussentuchit Member, Cedar Mountain Formation of Utah, USA. The single known specimen of this species (NCSM 29373) includes a well-preserved, disarticulated skull, partial axial column, and portions of the appendicular skeleton. Apomorphic traits are concentrated on the frontal, squamosal, braincase, and premaxilla, including the presence of three premaxillary teeth. Phylogenetic analyses using parsimony and Bayesian inference posit Iani as a North American rhabdodontomorph based on the presence of enlarged, spatulate teeth bearing up to 12 secondary ridges, maxillary teeth lacking a primary ridge, a laterally depressed maxillary process of the jugal, and a posttemporal foramen restricted to the squamosal, among other features. Prior to this discovery, neornithischian paleobiodiversity in the Mussentuchit Member was based primarily on isolated teeth, with only the hadrosauroid Eolambia caroljonesa named from macrovertebrate remains. Documentation of a possible rhabdodontomorph in this assemblage, along with published reports of an as-of-yet undescribed thescelosaurid, and fragmentary remains of ankylosaurians and ceratopsians confirms a minimum of five, cohabiting neornithischian clades in earliest Late Cretaceous terrestrial ecosystems of North America. Due to poor preservation and exploration of Turonian–Santonian assemblages, the timing of rhabdodontomorph extirpation in the Western Interior Basin is, as of yet, unclear. However, Iani documents survival of all three major clades of Early Cretaceous neornithischians (Thescelosauridae, Rhabdodontomorpha, and Ankylopollexia) into the dawn of the Late Cretaceous of North America.}, number={6}, journal={PLOS ONE}, author={Zanno, Lindsay E. and Gates, Terry A. and Avrahami, Haviv M. and Tucker, Ryan T. and Makovicky, Peter J.}, editor={Liu, JunEditor}, year={2023}, month={Jun} }
 @article{tucker_crowley_mohr_renaut_makovicky_zanno_2023, title={Exceptional age constraint on a fossiliferous sedimentary succession preceding the Cretaceous Thermal Maximum}, volume={51}, ISSN={["1943-2682"]}, DOI={10.1130/G51278.1}, abstractNote={Understanding the effects of climatic upheavals during the Early to Late Cretaceous transition is essential for characterizing the tempo of tectonically driven landscape modification and biological interchange; yet, current chronostratigraphic frameworks are too imprecise, even on regional scales, to address many outstanding questions. This includes the Mussentuchit Member of the uppermost Cedar Mountain Formation, central Utah (southwestern United States), which could provide crucial insights into these impacts within the Western Interior Basin of North America yet remains imprecisely constrained. Here, we present high-precision U-Pb zircon dates from four primary ash beds distributed across ∼50 km in central Utah that better constrain the timing of deposition of the Mussentuchit Member and the age of entombed fossils. Ages for ash beds are interpreted through a combination of Bayesian depositional age estimation and stratigraphic age modeling, resulting in posterior ages from 99.490 +0.057/−0.050 to 98.905 +0.158/−0.183 Ma. The age model predicts probabilistic ages for fossil localities between the ashes, including new ages for Moros intrepidus, Siats meekerorum, and several undescribed ornithischian dinosaur species of key interest for understanding the timing of faunal turnover in western North America. This new geochronology for the Mussentuchit Member offers unprecedented temporal insights into a volatile interval in Earth’s history.}, number={10}, journal={GEOLOGY}, author={Tucker, Ryan T. and Crowley, James L. and Mohr, Michael T. and Renaut, Ray K. and Makovicky, Peter J. and Zanno, Lindsay E.}, year={2023}, month={Oct}, pages={962–967} }
 @article{anne_canoville_edwards_schweitzer_zanno_2023, title={Independent Evidence for the Preservation of Endogenous Bone Biochemistry in a Specimen of Tyrannosaurus rex}, volume={12}, ISSN={["2079-7737"]}, DOI={10.3390/biology12020264}, abstractNote={Simple Summary Our understanding of what can preserve in the fossil record, and for how long, is constantly evolving with the use of new scientific techniques and exceptional fossil discoveries. In this study, we examine the state of preservation of a Tyrannosaurus rex that died about 66 million years ago. This specimen has previously been studied using a number of advanced methods, all of which have indicated preservation of original soft tissues and bone biomolecules. Here, we use synchrotron—a type of particle accelerator—analyses to generate data identifying and quantifying elements that constitute this fossil bone. We show that trace elements incorporated by the living animal during bone deposition and remodeling, such as zinc, are preserved in the fossil bone in a pattern similar to what is seen in modern bird bones. This pattern is not observed in a microscopically well preserved, but molecularly more degraded dinosaur, a herbivorous Tenontosaurus. These data further support the preservation of original biological material in this T. rex, suggesting new possibilities for deciphering extinct species life histories. This study also highlights that preservation of original biochemistry in fossils is specimen-specific and cannot be determined by pristine appearance alone. Abstract Biomolecules preserved in deep time have potential to shed light on major evolutionary questions, driving the search for new and more rigorous methods to detect them. Despite the increasing body of evidence from a wide variety of new, high resolution/high sensitivity analytical techniques, this research is commonly met with skepticism, as the long standing dogma persists that such preservation in very deep time (>1 Ma) is unlikely. The Late Cretaceous dinosaur Tyrannosaurus rex (MOR 1125) has been shown, through multiple biochemical studies, to preserve original bone chemistry. Here, we provide additional, independent support that deep time bimolecular preservation is possible. We use synchrotron X-ray fluorescence imaging (XRF) and X-ray absorption spectroscopy (XAS) to investigate a section from the femur of this dinosaur, and demonstrate preservation of elements (S, Ca, and Zn) associated with bone remodeling and redeposition. We then compare these data to the bone of an extant dinosaur (bird), as well as a second non-avian dinosaur, Tenontosaurus tilletti (OMNH 34784) that did not preserve any sign of original biochemistry. Our data indicate that MOR 1125 bone cortices have similar bone elemental distributions to that of an extant bird, which supports preservation of original endogenous chemistry in this specimen.}, number={2}, journal={BIOLOGY-BASEL}, author={Anne, Jennifer and Canoville, Aurore and Edwards, Nicholas P. and Schweitzer, Mary H. and Zanno, Lindsay E.}, year={2023}, month={Feb} }
 @article{button_zanno_2023, title={Neuroanatomy of the late Cretaceous <i>Thescelosaurus neglectus</i> (Neornithischia: Thescelosauridae) reveals novel ecological specialisations within Dinosauria}, volume={13}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-023-45658-3}, abstractNote={Abstract Ornithischian dinosaurs exhibited a diversity of ecologies, locomotory modes, and social structures, making them an ideal clade in which to study the evolution of neuroanatomy and behaviour. Here, we present a 3D digital reconstruction of the endocranial spaces of the latest Cretaceous neornithischian Thescelosaurus neglectus , in order to interpret the neuroanatomy and paleobiology of one of the last surviving non-avian dinosaurs. Results demonstrate that the brain of Thescelosaurus was relatively small compared to most other neornithischians, instead suggesting cognitive capabilities within the range of extant reptiles. Other traits include a narrow hearing range, with limited ability to distinguish high frequencies, paired with unusually well-developed olfactory lobes and anterior semicircular canals, indicating acute olfaction and vestibular sensitivity. This character combination, in conjunction with features of the postcranial anatomy, is consistent with specializations for burrowing behaviours in the clade, as evidenced by trace and skeletal fossil evidence in earlier-diverging thescelosaurids, although whether they reflect ecological adaptations or phylogenetic inheritance in T. neglectus itself is unclear. Nonetheless, our results provide the first evidence of neurological specializations to burrowing identified within Ornithischia, and non-avian dinosaurs more generally, expanding the range of ecological adaptations recognized within this major clade.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Button, David J. and Zanno, Lindsay E.}, year={2023}, month={Nov} }
 @article{renaut_tucker_king_crowley_hyland_zanno_2023, title={Timing of the Greenhorn transgression and OAE2 in Central Utah using CA-TIMS U-Pb zircon dating}, volume={146}, ISSN={["1095-998X"]}, DOI={10.1016/j.cretres.2022.105464}, abstractNote={Contextualizing subbasinal influences on accommodation and pace of the rapid landscape evolution during the base-level rise of the Upper Cretaceous (upper Cenomanian–lower Turonian) Greenhorn Cycle within the Western Interior of North America requires refined stratigraphic controls of key sediment successions. Herein, a blended analysis of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), chemical abrasion thermal ionization mass spectrometry (CA-TIMS), and δ13C isotopic data is utilized to identify two regionally significant ash-fall marker beds southeast of the Wasatch Plateau, specifically the TT1 and TT4, which bracket the Cenomanian–Turonian boundary and the Greenhorn Cycle transgression in the Western Interior Seaway (WIS). Based on our analysis of the recovered ash-fall zircons, a meaningful depositional age (DA) for the TT1 is 94.616 Ma ± 0.027 and 94.010 Ma ± 0.017 for the TT4 bentonite of the Tununk Shale. When coupled with the pre-existing biostratigraphic framework, correlation potential greatly increases with the (TT1) Naturita falling within the Sciponoceras gracile Assemblage Zone. Common molluscs associated with this biozone within the southern and central regions of Utah include Inoceramus pictus, Euomphaloceras spp., and Pycnodonte newberryi. The (TT4) Tununk within the upper portion of the Watinoceras coloradoense Assemblage Zone is commonly associated with the following mollusc genus within the areas to the south and north of the study area: Mytiloides and Morrowites. Furthermore, these dates constrain the Cenomanian–Turonian boundary, provide accurate chronostratigraphic markers for intra and interbasinal correlation and serve to strengthen global linkages to Ocean Anoxic Event 2 (OAE2) during the Greenhorn Cycle transgression.}, journal={CRETACEOUS RESEARCH}, author={Renaut, Ray K. and Tucker, Ryan T. and King, M. Ryan and Crowley, James L. and Hyland, Ethan G. and Zanno, Lindsay E.}, year={2023}, month={Jun} }
 @article{krumenacker_zanno_sues_2022, title={A partial tyrannosauroid femur from the mid-Cretaceous Wayan Formation of eastern Idaho, USA}, volume={6}, ISSN={["1937-2337"]}, DOI={10.1017/jpa.2022.42}, abstractNote={Abstract. The diversity of mid-Cretaceous tyrannosauroids is poorly understood. We describe a partial tyrannosauroid femur from the Albian–Cenomanian Wayan Formation of eastern Idaho that helps to fill in an important spatiotemporal gap in the North American record of tyrannosaurs. This specimen, consisting of the proximal half of the bone, is morphologically similar to the femur of Moros intrepidus, a small-bodied tyrannosauroid from the Cenomanian Mussentuchit Member of the Cedar Mountain Formation of Utah, but not referable to this taxon. The Wayan femur lacks an autapomorphy diagnostic for Moros intrepidus, indicating the presence of a previously unrecognized tyrannosauroid taxon in the early Late Cretaceous of Laramidia. Histological results indicate that, at the time of death, this individual was at least five years old, skeletally immature, and undergoing growth at a moderate rate. The addition of this tyrannosauroid to the Wayan-Vaughn Assemblage provides additional evidence for the widespread distribution of various tyrannosauroid taxa in Laramidia during the early Late Cretaceous.}, journal={JOURNAL OF PALEONTOLOGY}, author={Krumenacker, L. J. and Zanno, Lindsay E. and Sues, Hans-Dieter}, year={2022}, month={Jun} }
 @article{tucker_hyland_gates_king_roberts_foley_berndt_hanta_khansubha_aswasereelert_et al._2022, title={Age, depositional history, and paleoclimatic setting of Early Cretaceous dinosaur assemblages from the Sao Khua Formation (Khorat Group), Thailand}, volume={601}, ISSN={["1872-616X"]}, DOI={10.1016/j.palaeo.2022.111107}, abstractNote={We describe the sedimentology, geochronology, and geochemistry of the Early Cretaceus Sao Khua Formation of the Khorat Basin, northeastern Thailand, and report a temporal range adjustment for its dinosaurian assemblage. Facies analysis and architectural studies reveal that sedimentation occurred within a floodplain setting fed by large meandering bedload-rich channels. Interfluve areas comprised freshwater lakes and emergent areas subject to pedogenic modification. Multiple paleosol types are identified and geochemistry is indicative of a stable humid subtropical climate regime. Based on radiometric dating of detrital zircons (via LA-ICP-MS), we interpret that the middle part of the Sao Khua Formation was deposited no later than 133.8 (±1.8) Ma (late Valanginian), and grain ages collected from the overlying lowermost Phu Phan Fm constrain sedimentation of the upper part of the Sao Khua Formation to no earlier than 132.4 (±2.0) Ma (early Hauterivian). In consideration of the Early Cretaceous regional tectonic framework, we interpret that youthful igneous zircon grains are derived from the adjacent South China-Vietnam South Borneo Volcanic Arc. We establish that the entombed dinosaur biota (including members of the Ornithomimosauria, Spinosauridae, Megaraptora, and Somphospondylia) is ~5–9 million years older than previously recognized and that these records are among the oldest known globally for these clades. Constraining the age of the Sao Khua Formation indicates that the shift from sauropod-dominated, ornithischian depauperate ecosystems of the Sao Khua Formation to iguanodontian-rich ecosystems of the Khok Kruat Formation occurred sometime between the early Hauterivian and Aptian on the Khorat Plateau.}, journal={PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY}, author={Tucker, Ryan T. and Hyland, Ethan G. and Gates, Terry A. and King, M. Ryan and Roberts, Eric M. and Foley, Elliot K. and Berndt, David and Hanta, Rattanaphorn and Khansubha, Sasa-on and Aswasereelert, Wasinee and et al.}, year={2022}, month={Sep} }
 @article{chinzorig_beguesse_canoville_phillips_zanno_2022, title={Chronic fracture and osteomyelitis in a large-bodied ornithomimosaur with implications for the identification of unusual endosteal bone in the fossil record}, volume={10}, ISSN={["1932-8494"]}, url={https://doi.org/10.1002/ar.25069}, DOI={10.1002/ar.25069}, abstractNote={Paleopathological diagnoses provide key information on the macroevolutionary origin of disease as well as behavioral and physiological inferences that are inaccessible via direct observation of extinct organisms. Here we describe the external gross morphology and internal architecture of a pathologic right second metatarsal (MMNS VP‐6332) of a large‐bodied ornithomimid (~432 kg) from the Santonian (Upper Cretaceous) Eutaw Formation in Mississippi, using a combination of X‐ray computed microtomography (microCT) and petrographic histological analyses. X‐ray microCT imaging and histopathologic features are consistent with multiple complete, oblique to comminuted, minimally displaced mid‐diaphyseal cortical fractures that produce a “butterfly” fragment fracture pattern, and secondary osteomyelitis with a bone fistula formation. We interpret this as evidence of blunt force trauma to the foot that could have resulted from intra‐ or interspecific competition or predator–prey interaction, and probably impaired the function of the metatarsal as a weight‐bearing element until the animal's death. Of particular interest is the apparent decoupling of endosteal and periosteal pathological bone deposition in MMNS VP‐6332, which produces transverse sections exhibiting homogenously thick endosteal pathological bone in the absence of localized periosteal reactive bone. These distribution and depositional patterns are used as criteria for ruling out a pathological origin in favor of a reproductive one for unusual endosteal bone in fossil specimens. On the basis of MMNS VP‐6332, we suggest caution in their use to substantiate a medullary bone identification in extinct archosaurians.}, journal={ANATOMICAL RECORD-ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY}, author={Chinzorig, Tsogtbaatar and Beguesse, Kyla A. and Canoville, Aurore and Phillips, George and Zanno, Lindsay E.}, year={2022}, month={Oct} }
 @article{benson_brown_campione_cullen_evans_zanno_2022, title={Comment on "The influence of juvenile dinosaurs on community structure and diversity"}, volume={375}, ISSN={["1095-9203"]}, url={https://doi.org/10.1126/science.abj5976}, DOI={10.1126/science.abj5976}, abstractNote={Schroeder et al. (Reports, 26 February 2021, p. 941) reported a size gap among predatory dinosaur species. We argue that the supporting dataset is skewed toward Late Cretaceous North America and that the gap was likely absent during other intervals in most geographic regions. We urge broader consideration of this hypothesis, with quantitative evaluation of preservational and dataset biases. Description}, number={6578}, journal={SCIENCE}, author={Benson, Roger B. J. and Brown, Caleb M. and Campione, Nicolas E. and Cullen, Thomas M. and Evans, David C. and Zanno, Lindsay E.}, year={2022}, month={Jan} }
 @article{miller_avrahami_zanno_2022, title={Dental pathologies in lamniform and carcharhiniform sharks with comments on the classification and homology of double tooth pathologies in vertebrates}, volume={10}, ISSN={["2167-8359"]}, url={https://doi.org/10.7717/peerj.12775}, DOI={10.7717/peerj.12775}, abstractNote={Double tooth pathologies are important indicators of trauma, disease, diet, and feeding biomechanics, and are widely documented in mammals. However, diagnosis of double tooth pathologies in extinct non-mammalian vertebrates is complicated by several compounding factors including: a lack of shared terminology reflecting shared etiology, inconsistencies in definitions and key features within and outside of mammals (e.g., gemination, fusion, twinning, concrescence); differences in tooth morphology, heterodonty, regeneration, and implantation between mammals and non-mammalian vertebrates; and the unmet need for diagnostic criteria that can be applied to isolated teeth, which are common in the fossil record. Here we report on double tooth pathologies in the lamniform and carcharhiniform Cenozoic sharks Otodus megalodon (NCSM 33639) and Carcharhinus leucas (NCSM 33640, 33641). All three teeth bear a singular bifid crown with mirrored halves and abnormal internal microstructure—a single, bifurcating pulp cavity in C. leucas and a more than tripling of vessels in O. megalodon (from two to seven main ascending canals). We identify these abnormalities as likely examples of gemination due to their symmetry, which rules out fusion of tooth buds in one tooth file in different developmental stages in polyphyodont taxa; however, we note that incomplete forms of mesiodistal tooth fusion can be morphologically indistinguishable from gemination, and thus fusion cannot be rejected. We further compile and recategorize, when possible, the diversity of tooth pathologies in sharks. The identification of double tooth pathologies in O. megalodon and C. leucas has paleobiological implications. Such pathologies in sharks are largely hypothesized to stem from trauma to developing tooth buds. Carcharhinus leucas is known to feed on prey documented to cause feeding-related oral traumas (e.g., rays, sawfish, spiny fish, and sea urchins). However, O. megalodon, is considered to have largely fed on marine mammals, and perhaps turtles and/or fish, raising the possibility that the dietary diversity of this species is, as of yet, underappreciated. The genetic underpinnings of tooth morphogenesis and regeneration is highly conserved throughout vertebrate evolution, suggesting a homologous framework can be established. However, more research is needed to link developmental, paleobiological, and/or paleoenvironmental factors to gemination/fusion in polyphyodont taxa. We argue that the definitions and diagnostic criteria for dental pathologies in vertebrates require standardization in order to advance macroevolutionary studies of feeding trauma in deep time.}, journal={PEERJ}, author={Miller, Harrison S. and Avrahami, Haviv M. and Zanno, Lindsay E.}, year={2022}, month={May} }
 @article{gates_cai_hu_han_griffith_burgener_hyland_zanno_2022, title={Estimating ancient biogeographic patterns with statistical model discrimination}, volume={9}, ISSN={["1932-8494"]}, url={https://doi.org/10.1002/ar.25067}, DOI={10.1002/ar.25067}, abstractNote={The geographic ranges in which species live is a function of many factors underlying ecological and evolutionary contingencies. Observing the geographic range of an individual species provides valuable information about these historical contingencies for a lineage, determining the distribution of many distantly related species in tandem provides information about large‐scale constraints on evolutionary and ecological processes generally. We present a linear regression method that allows for the discrimination of various hypothetical biogeographical models for determining which landscape distributional pattern best matches data from the fossil record. The linear regression models used in the discrimination rely on geodesic distances between sampling sites (typically geologic formations) as the independent variable and three possible dependent variables: Dice/Sorensen similarity; Euclidean distance; and phylogenetic community dissimilarity. Both the similarity and distance measures are useful for full‐community analyses without evolutionary information, whereas the phylogenetic community dissimilarity requires phylogenetic data. Importantly, the discrimination method uses linear regression residual error to provide relative measures of support for each biogeographical model tested, not absolute answers or p‐values. When applied to a recently published dataset of Campanian pollen, we find evidence that supports two plant communities separated by a transitional zone of unknown size. A similar case study of ceratopsid dinosaurs using phylogenetic community dissimilarity provided no evidence of a biogeographical pattern, but this case study suffers from a lack of data to accurately discriminate and/or too much temporal mixing. Future research aiming to reconstruct the distribution of organisms across a landscape has a statistical‐based method for determining what biogeographic distributional model best matches the available data.}, journal={ANATOMICAL RECORD-ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY}, author={Gates, Terry A. and Cai, Hengrui and Hu, Yifei and Han, Xu and Griffith, Emily and Burgener, Landon and Hyland, Ethan and Zanno, Lindsay E.}, year={2022}, month={Sep} }
 @article{carr_napoli_brusatte_holtz_hone_williamson_zanno_2022, title={Insufficient Evidence for Multiple Species of Tyrannosaurus in the Latest Cretaceous of North America: A Comment on "The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus"}, volume={7}, ISSN={["1934-2845"]}, url={https://doi.org/10.1007/s11692-022-09573-1}, DOI={10.1007/s11692-022-09573-1}, abstractNote={Abstract The Late Cretaceous dinosaur Tyrannosaurus rex was recently split into three species based on the premise that variation in the T. rex hypodigm is exceptional, indicating cryptic species and “robust” and “gracile” morphs. The morphs are based on proportional ratios throughout the skeleton. The species are claimed to be stratigraphically separate, with an early robust species followed by robust and gracile descendants. There are problems with the hypothesis: the taxon diagnoses are based on two features that overlap between the species; several skulls cannot be identified based on the diagnoses; proportional comparisons between Tyrannosaurus and other theropods are based on incomparable samples; the tooth data are problematic; the stratigraphic framework divides the Hell Creek Formation into thirds, without the stratigraphic position of each specimen, or independent age control showing the subdivisions are coeval over the entire geographic area; previous work found variation in T. rex , but it cannot be parsed into discrete categories. We tested for “gracile” and “robust” morphs by analyzing the femoral and tooth ratios that were published in the multiple species study using agglomerative hierarchical clustering. The results found that each set of ratios are explained by one cluster, showing that dimorphism is not supported. We tested for exceptional variation of the femoral ratio of Tyrannosaurus ; we calculated the mean intraspecific robusticity for 112 species of living birds and 4 nonavian theropods. The results showed that the absolute variation in Tyrannosaurus is unexceptional and it does not indicate cryptic diversity. We conclude that “ T. regina ” and “ T. imperator ” are subjective junior synonyms of T. rex .}, journal={EVOLUTIONARY BIOLOGY}, author={Carr, Thomas D. and Napoli, James G. and Brusatte, Stephen L. and Holtz, Thomas R., Jr. and Hone, David W. E. and Williamson, Thomas E. and Zanno, Lindsay E.}, year={2022}, month={Jul} }
 @article{tsogtbaatar_cullen_phillips_rolke_zanno_2022, title={Large-bodied ornithomimosaurs inhabited Appalachia during the Late Cretaceous of North America}, volume={17}, ISSN={["1932-6203"]}, url={https://doi.org/10.1371/journal.pone.0266648}, DOI={10.1371/journal.pone.0266648}, abstractNote={Reconstructing the evolution, diversity, and paleobiogeography of North America’s Late Cretaceous dinosaur assemblages require spatiotemporally contiguous data; however, there remains a spatial and temporal disparity in dinosaur data on the continent. The rarity of vertebrate-bearing sedimentary deposits representing Turonian–Santonian ecosystems, and the relatively sparse record of dinosaurs from the eastern portion of the continent, present persistent challenges for studies of North American dinosaur evolution. Here we describe an assemblage of ornithomimosaurian materials from the Santonian Eutaw Formation of Mississippi. Morphological data coupled with osteohistological growth markers suggest the presence of two taxa of different body sizes, including one of the largest ornithomimosaurians known worldwide. The regression predicts a femoral circumference and a body mass of the Eutaw individuals similar to or greater than that of large-bodied ornithomimosaurs, Beishanlong grandis, and Gallimimus bullatus. The paleoosteohistology of MMNS VP-6332 demonstrates that the individual was at least ten years of age (similar to B. grandis [~375 kg, 13–14 years old at death]). Additional pedal elements share some intriguing features with ornithomimosaurs, yet suggest a larger-body size closer to Deinocheirus mirificus. The presence of a large-bodied ornithomimosaur in this region during this time is consistent with the relatively recent discoveries of early-diverging, large-bodied ornithomimosaurs from mid-Cretaceous strata of Laurasia (Arkansaurus fridayi and B. grandis). The smaller Eutaw taxon is represented by a tibia preserving seven growth cycles, with osteohistological indicators of decreasing growth, yet belongs to an individual approaching somatic maturity, suggesting the co-existence of medium- and large-bodied ornithomimosaur taxa during the Late Cretaceous Santonian of North America. The Eutaw ornithomimosaur materials provide key information on the diversity and distribution of North American ornithomimosaurs and Appalachian dinosaurs and fit with broader evidence of multiple cohabiting species of ornithomimosaurian dinosaurs in Late Cretaceous ecosystems of Laurasia.}, number={10}, journal={PLOS ONE}, author={Tsogtbaatar, Chinzorig and Cullen, Thomas and Phillips, George and Rolke, Richard and Zanno, Lindsay E.}, editor={Claessens, LeonEditor}, year={2022}, month={Oct} }
 @article{tucker_suarez_makovicky_zanno_2022, title={PARALIC SEDIMENTOLOGY OF THE MUSSENTUCHIT MEMBER COASTAL PLALN, CEDAR MOUNTAIN FORMATION, CENTRAL UTAH, USA}, volume={92}, ISSN={["1938-3681"]}, DOI={10.2110/jsr.2021.028}, abstractNote={
 Although intensified work on the volcaniclastic-rich sediments of the fossil-bearing Mussentuchit Member (uppermost Cedar Mountain Formation, Utah) has provided a refined chronostratigraphic framework, paleoenvironmental interpretations remain cryptic. To resolve this, we performed facies analysis and architectural reconstruction on exposed Mussentuchit Member outcrops south of Emery, central Utah, USA. Contrary to previous interpretations (fluvial, lacustrine), we identified a broad suite of facies that indicate that deposition occurred on the landward part of a paralic depocenter, influenced by both distal alluvial and proximal coastal systems. We conclude that the Mussentuchit Member was a sink for suspension-settling fines with most undergoing pedogenic alteration, analogous to the modern coastal plain of French Guiana (Wang et al. 2002; Anthony et al. 2010, 2014). However, this landward paralic depocenter was not uniform through time. Sedimentological evidence indicates landscape modification was ongoing, influenced by an altered base-level (high groundwater table, long residency of water in sediments, shifts in paleosol types, heavier to lighter δ18O, and distinct shifts in relative humidity (ε); common in coastal settings). If the above data is coupled with recent age data, we interpret that the Mussentuchit Member correlates to the S.B. 4 Greenhorn Regression (Thatcher Limestone) of the adjacent Western Interior Seaway to the east. As a landward paralic depocenter, the Mussentuchit would have been sensitive to base-level conditions in response to ongoing tectonic processes pushing the foredeep east, and lower paleo-CO2 levels coupled with a minor global sea-level fall (brief glacial phase) just before to the Cenomanian–Turonian Thermal Maximum. Altogether, our results not only strengthen linkages in the central Western Interior Seaway, but simultaneously results in novel linkages to near-coeval paralic depocenters across mid-Cenomanian North America.}, number={6}, journal={JOURNAL OF SEDIMENTARY RESEARCH}, author={Tucker, Ryan T. and Suarez, Celina A. and Makovicky, Peter J. and Zanno, Lindsay E.}, year={2022}, month={Jun}, pages={546–569} }
 @article{arbour_zanno_evans_2022, title={Palaeopathological evidence for intraspecific combat in ankylosaurid dinosaurs}, volume={18}, ISSN={["1744-957X"]}, DOI={10.1098/rsbl.2022.0404}, abstractNote={Ankylosaurid dinosaurs were heavily armoured herbivores with tails modified into club-like weapons. These tail clubs have widely been considered defensive adaptations wielded against predatory theropod dinosaurs. Here we argue instead that ankylosaurid tail clubs were sexually selected structures used primarily for intraspecific combat. We found pathological osteoderms (armour plates) in the holotype specimen of Zuul crurivastator, which are localized to the flanks in the hip region rather than distributed randomly across the body, consistent with injuries inflicted by lateral tail-swinging and ritualized combat. We failed to find convincing evidence for predation as a key selective pressure in the evolution of the tail club. High variation in tail club size through time, and delayed ontogenetic growth of the tail club further support the sexual selection hypothesis. There is little doubt that the tail club could have been used in defence when needed, but our results suggest that sexual selection drove the evolution of this impressive weapon. This changes the prevailing view of ankylosaurs, suggesting they were behaviorally complex animals that likely engaged in ritualized combat for social dominance as in other ornithischian dinosaurs and mammals.}, number={12}, journal={BIOLOGY LETTERS}, author={Arbour, Victoria M. and Zanno, Lindsay E. and Evans, David C.}, year={2022}, month={Dec} }
 @article{cilliers_tucker_crowley_zanno_2021, title={Age constraint for the Moreno Hill Formation (Zuni Basin) by CA-TIMS and LA-ICP-MS detrital zircon geochronology}, volume={9}, ISSN={["2167-8359"]}, url={https://doi.org/10.7717/peerj.10948}, DOI={10.7717/peerj.10948}, abstractNote={The “mid-Cretaceous” (~125–80 Ma) was punctuated by major plate-tectonic upheavals resulting in widespread volcanism, mountain-building, eustatic sea-level changes, and climatic shifts that together had a profound impact on terrestrial biotic assemblages. Paleontological evidence suggests terrestrial ecosystems underwent a major restructuring during this interval, yet the pace and pattern are poorly constrained. Current impediments to piecing together the geologic and biological history of the “mid-Cretaceous” include a relative paucity of terrestrial outcrop stemming from this time interval, coupled with a historical understudy of fragmentary strata. In the Western Interior of North America, sedimentary strata of the Turonian–Santonian stages are emerging as key sources of data for refining the timing of ecosystem transformation during the transition from the late-Early to early-Late Cretaceous. In particular, the Moreno Hill Formation (Zuni Basin, New Mexico) is especially important for detailing the timing of the rise of iconic Late Cretaceous vertebrate faunas. This study presents the first systematic geochronological framework for key strata within the Moreno Hill Formation. Based on the double-dating of (U-Pb) detrital zircons, via CA-TIMS and LA-ICP-MS, we interpret two distinct depositional phases of the Moreno Hill Formation (initial deposition after 90.9 Ma (middle Turonian) and subsequent deposition after 88.6 Ma (early Coniacian)), younger than previously postulated based on correlations with marine biostratigraphy. Sediment and the co-occurring youthful subset of zircons are sourced from the southwestern Cordilleran Arc and Mogollon Highlands, which fed into the landward portion of the Gallup Delta (the Moreno Hill Formation) via northeasterly flowing channel complexes. This work greatly strengthens linkages to other early Late Cretaceous strata across the Western Interior.}, journal={PEERJ}, author={Cilliers, Charl D. and Tucker, Ryan T. and Crowley, James L. and Zanno, Lindsay E.}, year={2021}, month={Mar} }
 @article{burgener_hyland_griffith_mitasova_zanno_gates_2021, title={An extreme climate gradient-induced ecological regionalization in the Upper Cretaceous Western Interior Basin of North America}, volume={133}, ISSN={["1943-2674"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85111073513&partnerID=MN8TOARS}, DOI={10.1130/B35904.1}, abstractNote={Abstract The Upper Cretaceous Western Interior Basin of North America provides a unique laboratory for constraining the effects of spatial climate patterns on the macroevolution and spatiotemporal distribution of biological communities across geologic timescales. Previous studies suggested that Western Interior Basin terrestrial ecosystems were divided into distinct southern and northern communities, and that this provincialism was maintained by a putative climate barrier at ∼50°N paleolatitude; however, this climate barrier hypothesis has yet to be tested. We present mean annual temperature (MAT) spatial interpolations for the Western Interior Basin that confirm the presence of a distinct terrestrial climate barrier in the form of a MAT transition zone between 48°N and 58°N paleolatitude during the final 15 m.y. of the Cretaceous. This transition zone was characterized by steep latitudinal temperature gradients and divided the Western Interior Basin into warm southern and cool northern biomes. Similarity analyses of new compilations of fossil pollen and leaf records from the Western Interior Basin suggest that the biogeographical distribution of primary producers in the Western Interior Basin was heavily influenced by the presence of this temperature transition zone, which in turn may have impacted the distribution of the entire trophic system across western North America.}, number={9-10}, journal={GEOLOGICAL SOCIETY OF AMERICA BULLETIN}, author={Burgener, Landon and Hyland, Ethan and Griffith, Emily and Mitasova, Helena and Zanno, Lindsay E. and Gates, Terry A.}, year={2021}, pages={2125–2136} }
 @article{cullen_zanno_larson_todd_currie_evans_2021, title={Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation}, volume={58}, ISSN={["1480-3313"]}, DOI={10.1139/cjes-2020-0145}, abstractNote={The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skele...}, number={9}, journal={CANADIAN JOURNAL OF EARTH SCIENCES}, author={Cullen, Thomas M. and Zanno, Lindsay and Larson, Derek W. and Todd, Erinn and Currie, Philip J. and Evans, David C.}, year={2021}, month={Sep}, pages={870–884} }
 @article{king_la croix_gates_anderson_zanno_2021, title={Glossifungites gingrasi n. isp., a probable subaqueous insect domicile from the Cretaceous Ferron Sandstone, Utah}, volume={95}, ISSN={["1937-2337"]}, DOI={10.1017/jpa.2020.115}, abstractNote={Abstract. A new ichnospecies, Glossifungites gingrasi n. isp., is described from multiple locations in basal sand-filled coastal plain distributary channels of the Turonian (Upper Cretaceous) Ferron Sandstone (central Utah). Glossifungites gingrasi n. isp. is attributed to the ichnogenus Glossifungites based on the presence of scratch imprints, passive fill, and a tongue-shaped structure, yet the new ichnospecies is distinct because it displays transverse bioglyphs that run perpendicular to the planiform structure, which contrasts to the axis parallel bioglyphs present in the ichnospecies G. saxicava. The transverse arrangement of ornamentation exhibited by G. gingrasi n. isp. is observed in modern subaqueous insect burrows produced by mayfly and chironomid larvae, and constitutes a way to differentiate insect-generated burrows from structures produced by crustaceans that are known to create other Glossifungites ichnospecies. Differentiating insect- from crustacean-generated burrows is significant because it provides a way to distinguish bioturbation by marine-recruited fauna from that produced by freshwater fauna in the rock record, making G. gingrasi n. isp. a valuable ichnological tool for paleoenvironmental and stratigraphic interpretation. While G. gingrasi n. isp. may represent a burrow created by a variety of filter-feeding subaqueous insects, the large size of G. gingrasi n. isp. in the Ferron Sandstone suggests that the largest specimens are probable mayfly burrows and supports the assertion that burrowing mayflies (e.g., Polymitarcyidae and Ephemeridae) adapted to domicile filter-feeding during or prior to the Turonian.}, number={3}, journal={JOURNAL OF PALEONTOLOGY}, author={King, M. Ryan and La Croix, Andrew D. and Gates, Terry A. and Anderson, Paul B. and Zanno, Lindsay E.}, year={2021}, month={May}, pages={427–439} }
 @article{canoville_zanno_zheng_schweitzer_2021, title={Keratan sulfate as a marker for medullary bone in fossil vertebrates}, url={https://doi.org/10.1111/joa.13388}, DOI={10.1111/joa.13388}, abstractNote={The ability to determine the sex of extinct dinosaurs by examining the bones they leave behind would revolutionize our understanding of their paleobiology; however, to date, definitive sex‐specific skeletal traits remain elusive or controversial. Although living dinosaurs (i.e., extant birds) exhibit a sex‐specific tissue called medullary bone that is unique to females, the confident identification of this tissue in non‐avian archosaurs has proven a challenge. Tracing the evolution of medullary bone is complicated by existing variation of medullary bone tissues in living species; hypotheses that medullary bone structure or chemistry varied during its evolution; and a lack of studies aimed at distinguishing medullary bone from other types of endosteal tissues with which it shares microstructural and developmental characteristics, such as pathological tissues. A recent study attempted to capitalize on the molecular signature of medullary bone, which, in living birds, contains specific markers such as the sulfated glycosaminoglycan keratan sulfate, to support the proposed identification of medullary bone of a non‐avian dinosaur specimen (Tyrannosaurus rex MOR 1125). Purported medullary bone samples of MOR 1125 reacted positively to histochemical analyses and the single pathological control tested (avian osteopetrosis) did not, suggesting the presence of keratan sulfate might serve to definitively discriminate these tissues for future studies. To further test these results, we sampled 20 avian bone pathologies of various etiologies (18 species), and several MB samples. Our new data universally support keratan sulfate as a reliable marker of medullary bone in birds. However, we also find that reactivity varies among pathological bone tissues, with reactivity in some pathologies indistinguishable from MB. In the current sample, some pathologies comprised of chondroid bone (often a major constituent of skeletal pathologies and developing fracture calluses in vertebrates) contain keratan sulfate. We note that beyond chemistry, chondroid bone shares many characteristics with medullary bone (fibrous matrix, numerous and large cell lacunae, potential endosteal origin, trabecular architecture) and medullary bone has even been considered by some to be a type of chondroid bone. Our results suggest that the presence of keratan sulfate is not exclusive evidence for MB, but rather must be used as one in a suite of criteria available for identifying medullary bone (and thus gravid females) in non‐avian dinosaur specimens. Future studies should investigate whether there are definite chemical or microstructural differences between medullary bone and reactive chondroid bone that can discriminate these tissues.}, journal={Journal of Anatomy}, author={Canoville, Aurore and Zanno, Lindsay E. and Zheng, Wenxia and Schweitzer, Mary H.}, year={2021}, month={Jun} }
 @article{liao_zanno_wang_xu_2021, title={Postcranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria)}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0257913}, abstractNote={Beipiaosaurus inexpectus, from the Lower Cretaceous Yixian Formation (Sihetun locality, near Beipiao), Liaoning, China, is a key taxon for understanding the early evolution of therizinosaurians. Since initial publication in 1999, only the cranial elements of this taxon have been described in detail. Here we present a detailed description of the postcranial skeletal anatomy of the holotype specimen of B. inexpectus, including two never before described dorsal vertebrae from the anterior half of the series. Based on these observations, and comparisons with the postcranial skeleton of therizinosaurian taxa named since the most recent diagnosis, we revised the diagnostic features for B. inexpectus adding three new possible autapomorphies (PII-3 shorter than PIII-4, subequal length of the pre- and postacetabular portions of the ilium, and equidimensional pubic peduncle of ilium). Additionally, we also propose three possible synapomorphies for more inclusive taxa (Therizinosauroidea and Therizinosauridae) and discuss implications for evolutionary trends within Therizinosauria. The newly acquired data from the postcranial osteology of the holotype specimen of B. inexpectus sheds light on our understanding of postcranial skeletal evolution and identification of therizinosaurians.}, number={9}, journal={PLOS ONE}, author={Liao, Chun-Chi and Zanno, Lindsay E. and Wang, Shiying and Xu, Xing}, year={2021}, month={Sep} }
 @article{tucker_zanno_huang_makovicky_2020, title={A refined temporal framework for newly discovered fossil assemblages of the upper Cedar Mountain Formation (Mussentuchit Member), Mussentuchit Wash, Central Utah}, volume={110}, ISSN={["1095-998X"]}, DOI={10.1016/j.cretres.2020.104384}, abstractNote={Detangling the pace and structure of biotic turnover between the late Early and early Late Cretaceous within the Western Interior of North America requires refined stratigraphic controls of fossiliferous sediments; however, to date, many key mid-Cretaceous strata remain understudied and only tenuously or coarsely correlated. Intensified data collection in the uppermost Cedar Mountain Formation (Mussentuchit Member) suggests preservation of an understudied volcanilithic archive that can provide key insight into this enigmatic period in North America's geological history. Here we utilize detrital zircon geochronology (coupling LA-ICP-MS and CA-TIMS) to contextualize the sedimentary history of the Mussentuchit Member within the region of Mussentuchit Wash, Central Utah and compare these data with previous approaches. This study finds that emplacement of contemporaneous volcanilithics occurred in two distinct phases. The first phase occurred no older than 96 Ma, and a subsequent younger phase occurred no older than 94 Ma. Secondly, this study finds preliminary evidence that both eruptions occurred within a westerly lying arc; however, it is evident that these represent different volcanic inliers and terranes. Finally, this study also finds that the Mussentuchit Member can be reliably subdivided into two informal lower and upper sub-members, with the potential to preserve two distinct, previously unified fossil assemblages. Our data provides both a refined localized framework for newly uncovered fossil assemblages within this particular Mussentuchit Wash depo-centre and serves to strengthen correlations between mid-Cretaceous strata across the Western Interior.}, journal={CRETACEOUS RESEARCH}, author={Tucker, Ryan T. and Zanno, Lindsay E. and Huang, Hui-Qing and Makovicky, Peter J.}, year={2020}, month={Jun} }
 @inbook{choiniere_zanno_balanoff_2020, place={Berkeley}, edition={3rd Edition}, title={Basal Maniraptora}, booktitle={The Dinosauria}, publisher={Cambridge University Press}, author={Choiniere, J. and Zanno, L.E. and Balanoff, A.}, editor={Makovicky, P.J. and Carrano, M. and Barrett, P. and Weishampel, D.Editors}, year={2020} }
 @article{woodward_tremaine_williams_zanno_horner_myhrvold_2020, title={Growing up Tyrannosaurus rex : Osteohistology refutes the pygmy “ Nanotyrannus ” and supports ontogenetic niche partitioning in juvenile Tyrannosaurus}, volume={6}, url={https://doi.org/10.1126/sciadv.aax6250}, DOI={10.1126/sciadv.aax6250}, abstractNote={Tyrannosaurus rex dominated its ecosystem by singularly exploiting the roles of mid- and large-sized carnivore as it grew up. Despite its iconic status as the king of dinosaurs, Tyrannosaurus rex biology is incompletely understood. Here, we examine femur and tibia bone microstructure from two half-grown T. rex specimens, permitting the assessments of age, growth rate, and maturity necessary for investigating the early life history of this giant theropod. Osteohistology reveals these were immature individuals 13 to 15 years of age, exhibiting growth rates similar to extant birds and mammals, and that annual growth was dependent on resource abundance. Together, our results support the synonomization of “Nanotyrannus” into Tyrannosaurus and fail to support the hypothesized presence of a sympatric tyrannosaurid species of markedly smaller adult body size. Our independent data contribute to mounting evidence for a rapid shift in body size associated with ontogenetic niche partitioning late in T. rex ontogeny and suggest that this species singularly exploited mid- to large-sized theropod niches at the end of the Cretaceous.}, number={1}, journal={Science Advances}, publisher={American Association for the Advancement of Science (AAAS)}, author={Woodward, Holly N. and Tremaine, Katie and Williams, Scott A. and Zanno, Lindsay E. and Horner, John R. and Myhrvold, Nathan}, year={2020}, month={Jan} }
 @article{canoville_schweitzer_zanno_2020, title={Identifying medullary bone in extinct avemetatarsalians: challenges, implications and perspectives}, volume={375}, ISSN={["1471-2970"]}, DOI={10.1098/rstb.2019.0133}, abstractNote={Medullary bone (MB) is a sex-specific tissue produced by female birds during the laying cycle, and it is hypothesized to have arisen within Avemetatarsalia, possibly outside Avialae. Over the years, researchers have attempted to define a set of criteria from which to evaluate the nature of purported MB-like tissues recovered from fossil specimens. However, we argue that the prevalence, microstructural and chemical variability of MB in Neornithes is, as of yet, incompletely known and thus current diagnoses of MB do not capture the extent of variability that exists in modern birds. Based on recently published data and our own observations of MB distribution and structure using computed tomography and histochemistry, we attempt to advance the discourse on identifying MB in fossil specimens. We propose: (i) new insights into the phylogenetic breadth and structural diversity of MB within extant birds; (ii) a reevaluation and refinement of the most recently published list of criteria suggested for confidently identifying MB in the fossil record; (iii) reconsideration of some prior identifications of MB-like tissues in fossil specimens by taking into account the newly acquired data; and (iv) discussions on the challenges of characterizing MB in Neornithes with the goal of improving its diagnosis in extinct avemetatarsalians. This article is part of the theme issue ‘Vertebrate palaeophysiology’.}, number={1793}, journal={PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES}, author={Canoville, Aurore and Schweitzer, Mary H. and Zanno, Lindsay}, year={2020}, month={Mar} }
 @article{schwab_young_neenan_walsh_witmer_herrera_allain_brochu_choiniere_clark_et al._2020, title={Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water}, volume={117}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.2002146117}, abstractNote={Significance During major evolutionary transitions, groups acquire a new body plan that allows them to colonize new habitats and behave in new ways. The evolution of swimming cetaceans from land-living mammals is a prime example. We document changes to the inner ear sensory system, involved in balance and equilibrium, as extinct crocodile relatives called thalattosuchians underwent a similar transition in the Mesozoic (ca. 182–125 mya). We find that open-ocean thalattosuchians developed strikingly compact and thickened bony labyrinth after a long semiaquatic phase and after modifying their skeleton to become better swimmers. This differs from cetaceans, which miniaturized their bony labyrinths soon after entering the water. Therefore, thalattosuchians and cetaceans took different evolutionary paths from land to water. Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but these transitions are more poorly understood. We use computed tomography to study changes in the inner ear vestibular system, involved in sensing balance and equilibrium, as one of these groups, extinct crocodile relatives called thalattosuchians, transitioned from terrestrial ancestors into pelagic (open ocean) swimmers. We find that the morphology of the vestibular system corresponds to habitat, with pelagic thalattosuchians exhibiting a more compact labyrinth with wider semicircular canal diameters and an enlarged vestibule, reminiscent of modified and miniaturized labyrinths of other marine reptiles and cetaceans. Pelagic thalattosuchians with modified inner ears were the culmination of an evolutionary trend with a long semiaquatic phase, and their pelagic vestibular systems appeared after the first changes to the postcranial skeleton that enhanced their ability to swim. This is strikingly different from cetaceans, which miniaturized their labyrinths soon after entering the water, without a prolonged semiaquatic stage. Thus, thalattosuchians and cetaceans became secondarily aquatic in different ways and at different paces, showing that there are different routes for the same type of transition.}, number={19}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Schwab, Julia A. and Young, Mark T. and Neenan, James M. and Walsh, Stig A. and Witmer, Lawrence M. and Herrera, Yanina and Allain, Ronan and Brochu, Christopher A. and Choiniere, Jonah N. and Clark, James M. and et al.}, year={2020}, month={May}, pages={10422–10428} }
 @article{button_zanno_2020, title={Repeated Evolution of Divergent Modes of Herbivory in Non-avian Dinosaurs}, volume={30}, ISSN={["1879-0445"]}, DOI={10.1016/j.cub.7019.10.050}, number={1}, journal={CURRENT BIOLOGY}, author={Button, David J. and Zanno, Lindsay E.}, year={2020}, month={Jan}, pages={158-+} }
 @article{kosch_zanno_2020, title={Sampling impacts the assessment of tooth growth and replacement rates in archosaurs: implications for paleontological studies}, url={https://doi.org/10.7717/peerj.9918}, DOI={10.7717/peerj.9918}, abstractNote={Dietary habits in extinct species cannot be directly observed; thus, in the absence of extraordinary evidence, they must be reconstructed with a combination of morphological proxies. Such proxies often include information on dental organization and function such as tooth formation time and tooth replacement rate. In extinct organisms, tooth formation times and tooth replacement rate are calculated, in part via extrapolation of the space between incremental lines in dental tissues representing daily growth (von Ebner Line Increment Width; VEIW). However, to date, little work has been conducted testing assumptions about the primary data underpinning these calculations, specifically, the potential impact of differential sampling and data extrapolation protocols. To address this, we tested a variety of intradental, intramandibular, and ontogentic sampling effects on calculations of mean VEIW, tooth formation times, and replacement rates using histological sections and CT reconstructions of a growth series of three specimens of the extant archosaurian Alligator mississippiensis. We find transect position within the tooth and transect orientation with respect to von Ebner lines to have the greatest impact on calculations of mean VEIW—a maximum number of VEIW measurements should be made as near to the central axis (CA) as possible. Measuring in regions away from the central axis can reduce mean VEIW by up to 36%, causing inflated calculations of tooth formation time. We find little demonstrable impact to calculations of mean VEIW from the practice of subsampling along a transect, or from using mean VEIW derived from one portion of the dentition to extrapolate for other regions of the dentition. Subsampling along transects contributes only minor variations in mean VEIW (<12%) that are dwarfed by the standard deviation (SD). Moreover, variation in VEIW with distance from the pulp cavity likely reflects idiosyncratic patterns related to life history, which are difficult to control for; however, we recommend increasing the number of VEIW measured to minimize this effect. Our data reveal only a weak correlation between mean VEIW and body length, suggesting minimal ontogenetic impacts. Finally, we provide a relative SD of mean VEIW for Alligator of 29.94%, which can be used by researchers to create data-driven error bars for tooth formation times and replacement rates in fossil taxa with small sample sizes. We caution that small differences in mean VEIW calculations resulting from non-standardized sampling protocols, especially in a comparative context, will produce inflated error in tooth formation time estimations that intensify with crown height. The same holds true for applications of our relative SD to calculations of tooth formation time in extinct taxa, which produce highly variable maximum and minimum estimates in large-toothed taxa (e.g., 718–1,331 days in Tyrannosaurus).}, journal={PeerJ}, author={Kosch, Jens C.D. and Zanno, Lindsay E.}, year={2020}, month={Sep} }
 @article{ksepka_balanoff_smith_bever_bhullar_bourdon_braun_burleigh_clarke_colbert_et al._2020, title={Tempo and Pattern of Avian Brain Size Evolution}, volume={30}, ISSN={["1879-0445"]}, DOI={10.1016/j.cub.2020.03.060}, abstractNote={<h2>Summary</h2> Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and theropod dinosaurs, we infer patterns of brain-body co-variation in deep time. Our study confirms that no significant increase in relative brain size accompanied the trend toward miniaturization or evolution of flight during the theropod-bird transition. Critically, however, theropods and basal birds show weaker integration between brain size and body size, allowing for rapid changes in the brain-body relationship that set the stage for dramatic shifts in early crown birds. We infer that major shifts occurred rapidly in the aftermath of the Cretaceous-Paleogene mass extinction within Neoaves, in which multiple clades achieved higher relative brain sizes because of a reduction in body size. Parrots and corvids achieved the largest brains observed in birds via markedly different patterns. Parrots primarily reduced their body size, whereas corvids increased body and brain size simultaneously (with rates of brain size evolution outpacing rates of body size evolution). Collectively, these patterns suggest that an early adaptive radiation in brain size laid the foundation for subsequent selection and stabilization.}, number={11}, journal={CURRENT BIOLOGY}, author={Ksepka, Daniel T. and Balanoff, Amy M. and Smith, N. Adam and Bever, Gabriel S. and Bhullar, Bhart-Anjan S. and Bourdon, Estelle and Braun, Edward L. and Burleigh, J. Gordon and Clarke, Julia A. and Colbert, Matthew W. and et al.}, year={2020}, month={Jun}, pages={2026-+} }
 @article{zanno_tucker_canoville_avrahami_gates_makovicky_2019, title={Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record}, volume={2}, ISSN={["2399-3642"]}, url={https://doi.org/10.1038/s42003-019-0308-7}, DOI={10.1038/s42003-019-0308-7}, abstractNote={To date, eco-evolutionary dynamics in the ascent of tyrannosauroids to top predator roles have been obscured by a 70-million-year gap in the North American (NA) record. Here we report discovery of the oldest Cretaceous NA tyrannosauroid, extending the lineage by ~15 million years. The new taxon-Moros intrepidus gen. et sp. nov.-is represented by a hind limb from an individual nearing skeletal maturity at 6-7 years. With a ~1.2-m limb length and 78-kg mass, M. intrepidus ranks among the smallest Cretaceous tyrannosauroids, restricting the window for rapid mass increases preceding the appearance of colossal eutyrannosaurs. Phylogenetic affinity with Asian taxa supports transcontinental interchange as the means by which iconic biotas of the terminal Cretaceous were established in NA. The unexpectedly diminutive and highly cursorial bauplan of NA's earliest Cretaceous tyrannosauroids reveals an evolutionary strategy reliant on speed and small size during their prolonged stint as marginal predators.}, number={1}, journal={COMMUNICATIONS BIOLOGY}, publisher={Springer Nature}, author={Zanno, Lindsay E. and Tucker, Ryan T. and Canoville, Aurore and Avrahami, Haviv M. and Gates, Terry A. and Makovicky, Peter J.}, year={2019}, month={Feb} }
 @article{hedrick_cordero_zanno_noto_dodson_2019, title={Quantifying shape and ecology in avian pedal claws: the relationship between the bony core and keratinous sheath}, DOI={10.1002/ece3.5507}, abstractNote={Abstract Terrestrial tetrapods use their claws to interact with their environments in a plethora of ways. Birds in particular have developed a diversity of claw shapes since they are often not bound to terrestrial locomotion and have heterogeneous body masses ranging several orders of magnitude. Numerous previous studies have hypothesized a connection between pedal claw shape and ecological mode in birds, yet have generated conflicting results, spanning from clear ecological groupings based on claw shape to a complete overlap of ecological modes. The majority of these studies have relied on traditional morphometric arc measurements of keratinous sheaths and have variably accounted for likely confounding factors such as body mass and phylogenetic relatedness. To better address the hypothesized relationship between ecology and claw shape in birds, we collected 580 radiographs allowing visualization of the bony core and keratinous sheath shape in 21 avian orders. Geometric morphometrics was used to quantify bony core and keratinous sheath shape and was compared to results using traditional arc measurements. Neither approach significantly separates bird claws into coarse ecological categories after integrating body size and phylogenetic relatedness; however, some separation between ecological groups is evident and we find a gradual shift from the claw shape of ground‐dwelling birds to those of predatory birds. Further, the bony claw core and keratinous sheath are significantly correlated, and the degree of functional integration does not differ across ecological groups. Therefore, it is likely possible to compare fossil bony cores with extant keratinous sheaths after applying corrections. Finally, traditional metrics and geometric morphometric shape are significantly, yet loosely correlated. Based on these results, future workers are encouraged to use geometric morphometric approaches to study claw geometry and account for confounding factors such as body size, phylogeny, and individual variation prior to predicting ecology in fossil taxa.}, journal={Ecology and Evolution}, author={Hedrick, B and Cordero, S and Zanno, L. and Noto, C. and Dodson, P.}, year={2019} }
 @article{canoville_schweitzer_zanno_2019, title={Systemic distribution of medullary bone in the avian skeleton: ground truthing criteria for the identification of reproductive tissues in extinct Avemetatarsalia}, volume={19}, ISSN={1471-2148}, url={http://dx.doi.org/10.1186/s12862-019-1402-7}, DOI={10.1186/s12862-019-1402-7}, abstractNote={Medullary bone (MB) is an estrogen-dependent, sex-specific tissue produced by female birds during lay and inferred to be present in extinct avemetatarsalians (bird-line archosaurs). Although preliminary studies suggest that MB can be deposited within most skeletal elements, these are restricted to commercial layers or hormonally treated male pigeons, which are poor analogues for wild birds. By contrast, studies in wild bird species noted the presence of MB almost exclusively within limb bones, spurring the misconception that MB deposition is largely restricted to these regions. These disparate claims have cast doubt on the nature of MB-like tissues observed in some extinct avemetatarsalians because of their “unusual” anatomical locations. Furthermore, previous work reported that MB deposition is related to blood supply and pneumatization patterns, yet these hypotheses have not been tested widely in birds. To document the skeletal distribution of MB across Neornithes, reassess previous hypotheses pertaining to its deposition/distribution patterns, and refine the set of criteria by which to evaluate the nature of purported MB tissue in extinct avemetatarsalians, we CT-scanned skeletons of 40 female birds (38 species) that died during the egg-laying cycle, recorded presence or absence of MB in 19 skeletal regions, and assessed pneumatization of stylopods. Selected elements were destructively analyzed to ascertain the chemical and histological nature of observed endosteal bone tissues in contentious skeletal regions. Although its skeletal distribution varies interspecifically, we find MB to be a systemic tissue that can be deposited within virtually all skeletal regions, including cranial elements. We also provide evidence that the deposition of MB is dictated by skeletal distribution patterns of both pneumaticity and bone marrow; two factors linked to ecology (body size, foraging). Hence, skeletal distribution of MB can be extensive in small-bodied and diving birds, but more restricted in large-bodied species or efficient flyers. Previously outlined anatomical locations of purported MB in extinct taxa are invalid criticisms against their potential reproductive nature. Moreover, the proposed homology of lung tissues between birds and some extinct avemetatarsalians permit us to derive a series of location-based predictions that can be used to critically evaluate MB-like tissues in fossil specimens.}, number={1}, journal={BMC Evolutionary Biology}, publisher={Springer Nature}, author={Canoville, Aurore and Schweitzer, Mary H. and Zanno, Lindsay E.}, year={2019}, month={Mar} }
 @article{arbour_zanno_2019, title={Tail Weaponry in Ankylosaurs and Glyptodonts: An Example of a Rare but Strongly Convergent Phenotype}, volume={3}, ISSN={1932-8486}, url={http://dx.doi.org/10.1002/ar.24093}, DOI={10.1002/ar.24093}, abstractNote={The unusual clubbed tails of glyptodonts among mammals and ankylosaurines among dinosaurs most likely functioned as weapons of intraspecific combat or interspecific defense and are characterized by stiffening of the distal tail and, in some taxa, expansion of the distal tail tip. Although similarities in tail weaponry have been noted as a potential example of convergent evolution, this hypothesis has not been tested quantitatively, particularly with metrics that can distinguish convergence from long‐term stasis, assess the relative strength of convergence, and identify potential constraints in the appearance of traits during the stepwise, independent evolution of these structures. Using recently developed metrics of convergence within a phylomorphospace framework, we document that convergence accounts for over 80% of the morphological evolution in traits associated with tail weaponry in ankylosaurs and glyptodonts. In addition, we find that ankylosaurs and glyptodonts shared an independently derived, yet constrained progression of traits correlated with the presence of a tail club, including stiffening of the distal tail as a precedent to expansion of the tail tip in both clades. Despite differences in the anatomical construction of the tail club linked to lineage‐specific historical contingency, these lineages experienced pronounced, quantifiable convergent evolution, supporting hypotheses of functional constraints and shared selective pressures on the evolution of these distinctive weapons. Anat Rec, 303:988–998, 2020. © 2019 Wiley Periodicals, Inc.}, journal={The Anatomical Record}, publisher={Wiley}, author={Arbour, Victoria M. and Zanno, Lindsay E.}, year={2019}, month={Mar} }
 @article{gates_tsogtbaatar_zanno_chinzorig_watabe_2018, title={A new iguanodontian (Dinosauria: Ornithopoda) from the Early Cretaceous of Mongolia}, volume={6}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.5300}, DOI={10.7717/peerj.5300}, abstractNote={We describe a new iguanodontian ornithopod, Choyrodon barsboldi gen. et sp. nov. from the Albian-aged Khuren Dukh Formation of Mongolia based on several partial skeletons interpreted to represent a subadult growth stage based on osteohistological features. This new taxon is diagnosed by many autapomorphies of the maxilla, nasal, lacrimal, opisthotic, predentary, and surangular. Choyrodon displays an unusual combination of traits, possessing an open antorbital fenestra (a primitive ornithopod trait) together with derived features such as a downturned dentary and enlarged narial fenestra. Histological imaging suggests that the type specimen of Choyrodon would have been a subadult at the time of death. Phylogenetic analysis of two different character matrices do not posit Choyrodon to be the sister taxon or to be more primitive than the iguanodontian Altirhinus kurzanovi, which is found in the same formation. The only resolved relationship of this new taxon is that it was hypothesized to be a sister-taxon with the North American species Eolambia caroljonesa. Though discovered in the same formation and Choyrodon being smaller-bodied than Altirhinus, it does not appear that the former species is an ontogimorph of the latter. Differences in morphology and results of the phylogenetic analyses support their distinction although more specimens of both species will allow better refinement of their uniqueness.}, journal={PeerJ}, publisher={PeerJ}, author={Gates, Terry A. and Tsogtbaatar, Khishigjav and Zanno, Lindsay E. and Chinzorig, Tsogtbaatar and Watabe, Mahito}, year={2018}, month={Aug}, pages={e5300} }
 @article{avrahami_gates_heckert_makovicky_zanno_2018, title={A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America}, volume={6}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.5883}, DOI={10.7717/peerj.5883}, abstractNote={The vertebrate fauna of the Late Cretaceous Mussentuchit Member of the Cedar Mountain Formation has been studied for nearly three decades, yet the fossil-rich unit continues to produce new information about life in western North America approximately 97 million years ago. Here we report on the composition of the Cliffs of Insanity (COI) microvertebrate locality, a newly sampled site containing perhaps one of the densest concentrations of microvertebrate fossils yet discovered in the Mussentuchit Member. The COI locality preserves osteichthyan, lissamphibian, testudinatan, mesoeucrocodylian, dinosaurian, metatherian, and trace fossil remains and is among the most taxonomically rich microvertebrate localities in the Mussentuchit Member. To better refine taxonomic identifications of isolated theropod dinosaur teeth, we used quantitative analyses of taxonomically comprehensive databases of theropod tooth measurements, adding new data on theropod tooth morphodiversity in this poorly understood interval. We further provide the first descriptions of tyrannosauroid premaxillary teeth and document the earliest North American record of adocid remains, extending the appearance of this ancestrally Asian clade by 5 million years in western North America and supporting studies of pre-Cenomaninan Laurasian faunal exchange across Beringia. The overabundance of mesoeucrocodylian remains at the COI locality produces a comparatively low measure of relative biodiversity when compared to other microvertebrate sites in the Mussentuchit Member using both raw and subsampling methods. Much more microvertebrate research is necessary to understand the roles of changing ecology and taphonomy that may be linked to transgression of the Western Interior Seaway or microhabitat variation.}, journal={PeerJ}, publisher={PeerJ}, author={Avrahami, Haviv M. and Gates, Terry A. and Heckert, Andrew B. and Makovicky, Peter J. and Zanno, Lindsay E.}, year={2018}, month={Nov}, pages={e5883} }
 @article{hoffman_heckert_zanno_2018, title={Disparate Growth Strategies within Aetosauria: Novel Histologic Data from the Aetosaur Coahomasuchus chathamensis.}, volume={302}, ISSN={["1932-8494"]}, DOI={10.1002/ar.24019}, abstractNote={Aetosaurs comprise a clade of quadrupedal, armored, omnivores to herbivores that lived across much of the supercontinent of Pangea during the Late Triassic. Their relative abundance in many units, and the rarity of other Triassic herbivores, points to them as key components of Late Triassic ecosystems. Debate persists about whether they were growing more or less slowly when compared to extant crocodylians, and bone histology is sparsely sampled within the group. We undertook a histological examination of Coahomasuchus chathamensis to address its ontogenetic trajectory and characterize its histology. We sampled a paramedian osteoderm from the holotype specimen, as well as five osteoderms (two paramedian, one lateral, and two of uncertain position) and two incomplete limb bones (radius and fibula), from referred specimens discovered at the type locality. Using these we estimated specimen ages with lines of arrested growth (LAGs) to determine that the study individuals reached from 2 to 7 years old. All of the sampled elements contained woven-fibered bone with extensive vasculature within the internal cortex. In some specimens, more poorly vascularized, parallel-fibered bone is evident externally. The holotype of C. chathamensis represents a juvenile individual, and raises the possibility that the holotype of C. kahleorum is a juvenile as well, complicating aetosaur systematics and diversity. When compared to aetosaurs of similar size, it is clear that C. chathamensis was growing comparatively rapidly, about 3 times the rate of similarly sized specimens of Aetosauroides scagliai from Argentina. This discovery reveals the presence of disparate growth strategies within Aetosauria. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.}, number={9}, journal={The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology}, author={Hoffman, DK​ and Heckert, AB and Zanno, LE}, year={2018}, pages={1504–1515} }
 @article{arbour_zanno_2018, title={The evolution of tail weaponization in amniotes}, volume={285}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2017.2299}, DOI={10.1098/rspb.2017.2299}, abstractNote={Weaponry, for the purpose of intraspecific combat or predator defence, is one of the most widespread animal adaptations, yet the selective pressures and constraints governing its phenotypic diversity and skeletal regionalization are not well understood. Here, we investigate the evolution of tail weaponry in amniotes, a rare form of weaponry that nonetheless evolved independently among a broad spectrum of life including mammals, turtles and dinosaurs. Using phylogenetic comparative methods, we test for links between morphology, ecology and behaviour in extant amniotes known to use the tail as a weapon, and in extinct taxa bearing osseous tail armaments. We find robust ecological and morphological correlates of both tail lashing behaviour and bony tail weaponry, including large body size, body armour and herbivory, suggesting these life-history parameters factor into the evolution of antipredator behaviours and tail armaments. We suggest that the evolution of tail weaponry is rare because large, armoured herbivores are uncommon in extant terrestrial faunas, as they have been throughout evolutionary history.}, number={1871}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Arbour, Victoria M. and Zanno, Lindsay E.}, year={2018}, month={Jan}, pages={20172299} }
 @book{king_gates_gingras_zanno_pemberton_2018, title={Transgressive erosion expressed as a Rhizocorallium ​ -dominated xylic firmground: an example from the Blackhawk Formation, Utah}, volume={33}, ISSN={["1938-5323"]}, DOI={10.2110/palo.2016.111}, abstractNote={Abstract:  Horizontal and inclined U-shaped trace fossils are commonly associated with the Cruziana and Glossifungites ichnofacies, but have rarely been described as a component of the Teredolites ichnofacies (xylic substrates). This study provides several examples of morphologies of Glossifungites saxicava from the Campanian Sunnyside Coal (Blackhawk Formation) that exhibit both xenoglyphs and bioglyphs. Glossifungites along this surface are locally present as compound ?Thalassinoides suevicus-Glossifungites, which may represent a combination of commensalism, an exploited structural weakness, refugium from predators, and/or a secondary behavior of the presumed crustacean tracemakers. The trace-fossil assemblage also contains Teredolites clavatus and Teredolites longissimus and Radichnus isp. locally. Stratigraphically, this trace assemblage is important because it marks a marine flooding surface/transgressive surface of erosion between the Sunnyside and Grassy members of the Blackhawk Formation.}, number={1}, journal={PALAIOS}, publisher={PALAIOS}, author={King, M.R. and Gates, T.A. and Gingras, M.K. and Zanno, L.E. and Pemberton, G.}, year={2018}, pages={29–35} }
 @article{hoffman_heckert_zanno_2018, title={Under the armor: X-ray computed tomographic reconstruction of the internal skeleton of Coahomasuchus chathamensis (Archosauria: Aetosauria) from the Upper Triassic of North Carolina, USA, and a phylogenetic analysis of Aetosauria}, volume={6}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.4368}, DOI={10.7717/peerj.4368}, abstractNote={Aetosauria is a clade of heavily armored, quadrupedal omnivorous to herbivorous archosaurs known from the Late Triassic across what was the supercontinent of Pangea. Their abundance in many deposits relative to the paucity of other Triassic herbivores indicates that they were key components of Late Triassic ecosystems. However, their evolutionary relationships remain contentious due, in large part, to their extensive dermal armor, which often obstructs observation of internal skeletal anatomy and limits access to potentially informative characters. In an attempt to address this problem we reanalyzed the holotype of a recently described species of Coahomasuchus, C. chathamensis, from the Sanford sub-basin of North Carolina using computed tomography (CT). CT scans of the holotype specimen clarify preservation of the skeleton, revealing several articulated vertebrae and ribs, an isolated vertebra, left ulna, left scapula, and the right humerus, though none of the material resulted in updated phylogenetic scorings. Reexamination of aetosaur materials from the holotype locality also indicates that several isolated osteoderms and elements of the appendicular skeleton are newly referable. Based on these results, we update the Coahomasuchus chathamensis hypodigm and conduct a revised phylogenetic analysis with improved character scorings for Coahomasuchus and several other aetosaurs. Our study recovers Coahomasuchus in a polytomy with Aetosaurus and the Typothoracinae, in contrast with a recent analysis that recovered Coahomasuchus as a wild-card taxon.}, journal={PeerJ}, publisher={PeerJ}, author={Hoffman, Devin K. and Heckert, Andrew B. and Zanno, Lindsay E.}, year={2018}, month={Feb}, pages={e4368} }
 @article{mcdonald_gates_zanno_makovicky_2017, title={Anatomy, taphonomy, and phylogenetic implications of a new specimen of Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation, Utah, USA}, volume={12}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0176896}, DOI={10.1371/journal.pone.0176896}, abstractNote={Background Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchit Member of the Cedar Mountain Formation of Utah, and one of the most completely known non-hadrosaurid iguanodontians from North America. In addition to the large holotype and paratype partial skulls, copious remains of skeletally immature individuals, including three bonebeds, have been referred to E. caroljonesa. Nevertheless, aspects of the postcranial anatomy of this taxon, particularly the pelvic girdle, have remained ambiguous due to the lack of associated postcranial material of larger, more mature individuals. Methodology/Principal findings Here we describe a recently discovered associated partial postcranial skeleton of a large Eolambia caroljonesa. This specimen, FMNH PR 3847, provides new anatomical data regarding the vertebral column and pelvic girdle, supplementing previous diagnoses and descriptions of E. caroljonesa. A new phylogenetic analysis incorporating information from FMNH PR 3847 places E. caroljonesa as a basal hadrosauromorph closely related to Protohadros byrdi from the Cenomanian Woodbine Formation of Texas. Histological analysis of FMNH PR 3847 reveals that it represents a subadult individual eight to nine years of age. Taphonomic analysis indicates that FMNH PR 3847 was preserved in a crevasse splay deposit, along with an unusual abundance of small crocodylomorph material. Conclusions/Significance FMNH PR 3847 provides a wealth of new morphological data, adding to the anatomical and systematic characterization of Eolambia caroljonesa, and histological data, revealing new information on growth history in a basal hadrosauromorph. Taphonomic characterization of FMNH PR 3847 and associated vertebrate material will allow comparison with other vertebrate localities in the Mussentuchit Member of the Cedar Mountain Formation.}, number={5}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={McDonald, Andrew T. and Gates, Terry A. and Zanno, Lindsay E. and Makovicky, Peter J.}, editor={Spigelman, MarkEditor}, year={2017}, month={May}, pages={e0176896} }
 @article{button_you_kirkland_zanno_2017, title={Incremental growth of therizinosaurian dental tissues: implications for dietary transitions in Theropoda}, volume={5}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.4129}, DOI={10.7717/peerj.4129}, abstractNote={Previous investigations document functional and phylogenetic signals in the histology of dinosaur teeth. In particular, incremental lines in dentin have been used to determine tooth growth and replacement rates in several dinosaurian clades. However, to date, few studies have investigated the dental microstructure of theropods in the omnivory/herbivory spectrum. Here we examine dental histology of Therizinosauria, a clade of large-bodied theropods bearing significant morphological evidence for herbivory, by examining the teeth of the early-diverging therizinosaurian Falcarius utahensis, and an isolated tooth referred to Suzhousaurus megatherioides, a highly specialized large-bodied representative. Despite attaining some of the largest body masses among maniraptoran theropod dinosaurs, therizinosaurian teeth are diminutive, measuring no more than 0.90 cm in crown height (CH) and 0.38 cm in crown base length (CBL). Comparisons with other theropods and non-theropodan herbivorous dinosaurs reveals that when controlling for estimated body mass, crown volume in therizinosaurians plots most closely with dinosaurs of similar dietary strategy as opposed to phylogenetic heritage. Analysis of incremental growth lines in dentin, observed in thin sections of therizinosaurian teeth, demonstrates that tooth growth rates fall within the range of other archosaurs, conforming to hypothesized physiological limitations on the production of dental tissues. Despite dietary differences between therizinosaurians and hypercarnivorous theropods, the types of enamel crystallites present and their spatial distribution—i.e., the schmelzmuster of both taxa—is limited to parallel enamel crystallites, the simplest form of enamel and the plesiomorphic condition for Theropoda. This finding supports previous hypotheses that dental microstructure is strongly influenced by phylogeny, yet equally supports suggestions of reduced reliance on oral processing in omnivorous/herbivorous theropods rather than the microstructural specializations to diet exhibited by non-theropodan herbivorous dinosaurs. Finally, although our sample is limited, we document a significant reduction in the rate of enamel apposition contrasted with increased relative enamel thickness between early and later diverging therizinosaurians that coincides with anatomical evidence for increased specializations to herbivory in the clade.}, journal={PeerJ}, publisher={PeerJ}, author={Button, Khai and You, Hailu and Kirkland, James I. and Zanno, Lindsay}, year={2017}, month={Dec}, pages={e4129} }
 @article{arbour_zanno_gates_2016, title={Ankylosaurian dinosaur palaeoenvironmental associations were influenced by extirpation, sea-level fluctuation, and geodispersal}, volume={449}, ISSN={0031-0182}, url={http://dx.doi.org/10.1016/j.palaeo.2016.02.033}, DOI={10.1016/j.palaeo.2016.02.033}, abstractNote={More species of nodosaurid ankylosaurians than ankylosaurid ankylosaurians have been found in marine sediments, and some previous quantitative studies of global dinosaur occurrences provide support for an association between nodosaurids and marine depositional environments. We compiled a dataset of global ankylosaurian occurrences and found that the geographic distribution of marine ankylosaurian occurrences is regionally biased with 54% of records stemming from western North America in the Cretaceous—a time of regional highstands in sea level and epicontinental flooding, coupled with differential extirpation of ankylosaurian subclades inhabiting the Western Interior Basin (WIB). Within the Western Interior Basin, we found little statistical support for an association between ankylosaurian subclades and palaeoenvironment in a chronological context. Only the Albian–Cenomanian transgressive–regressive cycle had statistical support for an overabundance of nodosaurids in marine environments compared to ankylosaurids. The apparent overabundance of nodosaurids relative to ankylosaurids in marine sediments in the Western Interior Basin overall cannot be decoupled from the extirpation of North American ankylosaurids during the Cenomanian and the subsequent absence of ankylosaurids in North America during the Turonian to early Campanian prior to the immigration of Asian ankylosaurine ankylosaurids. The North American ankylosaurian record highlights the difficulty in interpreting habitat preferences in the context of a shifting seaway, regional extinctions, and intercontinental dispersals.}, journal={Palaeogeography, Palaeoclimatology, Palaeoecology}, publisher={Elsevier BV}, author={Arbour, Victoria M. and Zanno, Lindsay E. and Gates, Terry}, year={2016}, month={May}, pages={289–299} }
 @article{gates_organ_zanno_2016, title={Bony cranial ornamentation linked to rapid evolution of gigantic theropod dinosaurs}, volume={7}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/ncomms12931}, DOI={10.1038/ncomms12931}, abstractNote={Exaggerated cranial structures such as crests and horns, hereafter referred to collectively as ornaments, are pervasive across animal species. These structures perform vital roles in visual communication and physical interactions within and between species. Yet the origin and influence of ornamentation on speciation and ecology across macroevolutionary time scales remains poorly understood for virtually all animals. Here, we explore correlative evolution of osseous cranial ornaments with large body size in theropod dinosaurs using a phylogenetic comparative framework. We find that body size evolved directionally toward phyletic giantism an order of magnitude faster in theropod species possessing ornaments compared with unadorned lineages. In addition, we find a body mass threshold below which bony cranial ornaments do not originate. Maniraptoriform dinosaurs generally lack osseous cranial ornaments despite repeatedly crossing this body size threshold. Our study provides novel, quantitative support for a shift in selective pressures on socio-sexual display mechanisms in theropods coincident with the evolution of pennaceous feathers.}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Gates, Terry A. and Organ, Chris and Zanno, Lindsay E.}, year={2016}, month={Sep} }
 @article{schweitzer_zheng_zanno_werning_sugiyama_2016, title={Chemistry supports the identification of gender-specific reproductive tissue in Tyrannosaurus rex}, volume={6}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/srep23099}, DOI={10.1038/srep23099}, abstractNote={Medullary bone (MB), an estrogen-dependent reproductive tissue present in extant gravid birds, is texturally, histologically and compositionally distinct from other bone types. Phylogenetic proximity led to the proposal that MB would be present in non-avian dinosaurs, and recent studies have used microscopic, morphological, and regional homologies to identify this reproductive tissue in both theropod and ornithischian dinosaurs. Here, we capitalize on the unique chemical and histological fingerprint of MB in birds to characterize, at the molecular level, MB in the non-avian theropod Tyrannosaurus rex (MOR 1125), and show that the retention of original molecular components in fossils allows deeper physiological and evolutionary questions to be addressed.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Schweitzer, Mary Higby and Zheng, Wenxia and Zanno, Lindsay and Werning, Sarah and Sugiyama, Toshie}, year={2016}, month={Mar} }
 @article{drymala_zanno_2016, title={Osteology of Carnufex carolinensis (Archosauria: Psuedosuchia) from the Pekin Formation of North Carolina and Its Implications for Early Crocodylomorph Evolution}, volume={11}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0157528}, DOI={10.1371/journal.pone.0157528}, abstractNote={Crocodylomorphs originated in the Late Triassic and were the only crocodile-line archosaurs to survive the end-Triassic extinction. Recent phylogenetic analyses suggest that the closest relatives of these generally gracile, small-bodied taxa were a group of robust, large-bodied predators known as rauisuchids implying a problematic morphological gap between early crocodylomorphs and their closest relatives. Here we provide a detailed osteological description of the recently named early diverging crocodylomorph Carnufex carolinensis from the Upper Triassic Pekin Formation of North Carolina and assess its phylogenetic position within the Paracrocodylomorpha. Carnufex displays a mosaic of crocodylomorph, rauisuchid, and dinosaurian characters, as well as highly laminar cranial elements and vertebrae, ornamented dermal skull bones, a large, subtriangular antorbital fenestra, and a reduced forelimb. A phylogenetic analysis utilizing a comprehensive dataset of early paracrocodylomorphs and including seven new characters and numerous modifications to characters culled from the literature recovers Carnufex carolinensis as one of the most basal members of Crocodylomorpha, in a polytomy with two other large bodied taxa (CM 73372 and Redondavenator). The analysis also resulted in increased resolution within Crocodylomorpha and a monophyletic clade containing the holotype and two referred specimens of Hesperosuchus as well as Dromicosuchus. Carnufex occupies a key transition at the origin of Crocodylomorpha, indicating that the morphology typifying early crocodylomorphs appeared before the shift to small body size.}, number={6}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Drymala, Susan M. and Zanno, Lindsay E.}, editor={Claessens, LeonEditor}, year={2016}, month={Jun}, pages={e0157528} }
 @article{zanno_tsogtbaatar_chinzorig_gates_2016, title={Specializations of the mandibular anatomy and dentition of Segnosaurus galbinensis (Theropoda: Therizinosauria)}, volume={4}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.1885}, DOI={10.7717/peerj.1885}, abstractNote={Definitive therizinosaurid cranial materials are exceptionally rare, represented solely by an isolated braincase and tooth in the North American taxon Nothronychus mckinleyi, the remarkably complete skull of the Asian taxon Erlikosaurus andrewsi, and the lower hemimandibles of Segnosaurus galbinensis. To date, comprehensive descriptions of the former taxa are published; however, the mandibular materials of S. galbinensis have remained largely understudied since their initial description in 1979. Here we provide a comprehensive description of the well-preserved hemimandibles and dentition of S. galbinensis (MPC-D 100/80), from the Upper Cretaceous Bayanshiree Formation, Gobi Desert, Mongolia. The subrectangular and ventrally displaced caudal hemimandible, extreme ventral deflection of the rostral dentary, and edentulism of the caudal dentary of S. galbinensis are currently apomorphic among therizinosaurians. Unique, unreported dental traits including lingually folded mesial carinae, development of a denticulated triangular facet on the distal carinae near the cervix, and extracarinal accessory denticles, suggest a highly specialized feeding strategy in S. galbinensis. The presence of triple carinae on the distalmost lateral tooth crowns is also unique, although may represent an abnormality. Contrasted with the simplistic dentition of the contemporaneous therizinosaurid E. andrewsi, the dentition of S. galbinensis is indicative of niche partitioning in food acquisition, processing, or resources among known therizinosaurids inhabiting Asian ecosystems in the Late Cretaceous. Although not quantitatively correlated with diet, this suite of specializations is otherwise unique among theropod dinosaurs and supports derived inferences of facultative or obligate herbivory in therizinosaurids, ultimately adding novel information to our understanding of ecomorphology in theropods.}, journal={PeerJ}, publisher={PeerJ}, author={Zanno, Lindsay E. and Tsogtbaatar, Khishigjav and Chinzorig, Tsogtbaatar and Gates, Terry A.}, year={2016}, month={Mar}, pages={e1885} }
 @article{arbour_zanno_larson_evans_sues_2016, title={The furculae of the dromaeosaurid dinosaur Dakotaraptor steini are trionychid turtle entoplastra}, volume={4}, ISSN={2167-8359}, url={http://dx.doi.org/10.7717/peerj.1691}, DOI={10.7717/peerj.1691}, abstractNote={Dakotaraptor steini is a recently described dromaeosaurid dinosaur from the Upper Cretaceous (Maastrichtian) Hell Creek Formation of South Dakota. Included within the D. steini hypodigm are three elements originally identified as furculae, one of which was made part of the holotype specimen. We show that the elements described as D. steini ‘furculae’ are not theropod dinosaur furculae, but are rather trionychid turtle entoplastra referable to cf. Axestemys splendida. The hypodigm of D. steini should be adjusted accordingly.}, journal={PeerJ}, publisher={PeerJ}, author={Arbour, Victoria M. and Zanno, Lindsay E. and Larson, Derek W. and Evans, David C. and Sues, Hans-Dieter}, year={2016}, month={Feb}, pages={e1691} }
 @article{zanno_drymala_nesbitt_schneider_2015, title={Early crocodylomorph increases top tier predator diversity during rise of dinosaurs}, volume={5}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/srep09276}, DOI={10.1038/srep09276}, abstractNote={Triassic predatory guild evolution reflects a period of ecological flux spurred by the catastrophic end-Permian mass extinction and terminating with the global ecological dominance of dinosaurs in the early Jurassic. In responding to this dynamic ecospace, terrestrial predator diversity attained new levels, prompting unique trophic webs with a seeming overabundance of carnivorous taxa and the evolution of entirely new predatory clades. Key among these was Crocodylomorpha, the largest living reptiles and only one of two archosaurian lineages that survive to the present day. In contrast to their existing role as top, semi-aquatic predators, the earliest crocodylomorphs were generally small-bodied, terrestrial faunivores, occupying subsidiary (meso) predator roles. Here we describe Carnufex carolinensis a new, unexpectedly large-bodied taxon with a slender and ornamented skull from the Carnian Pekin Formation (~231 Ma), representing one of the oldest and earliest diverging crocodylomorphs described to date. Carnufex bridges a problematic gap in the early evolution of pseudosuchians by spanning key transitions in bauplan evolution and body mass near the origin of Crocodylomorpha. With a skull length of >50 cm, the new taxon documents a rare instance of crocodylomorphs ascending to top-tier predator guilds in the equatorial regions of Pangea prior to the dominance of dinosaurs.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Zanno, Lindsay E. and Drymala, Susan and Nesbitt, Sterling J. and Schneider, Vincent P.}, year={2015}, month={Mar} }
 @article{hedrick_zanno_wolfe_dodson_2015, title={The Slothful Claw: Osteology and Taphonomy of Nothronychus mckinleyi and N. graffami (Dinosauria: Theropoda) and Anatomical Considerations for Derived Therizinosaurids}, volume={10}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0129449}, DOI={10.1371/journal.pone.0129449}, abstractNote={Nothronychus was the first definitive therizinosaurian discovered in North America and currently represents the most specialized North American therizinosaurian genus. It is known from two species, No. mckinleyi from the Moreno Hill Formation (middle Turonian) in west-central New Mexico, and No. graffami from the Tropic Shale (early Turonian) in south-central Utah. Both species are represented by partial to nearly complete skeletons that have helped elucidate evolutionary trends in Therizinosauria. In spite of the biogeographical and evolutionary importance of these two taxa, neither has received a detailed description. Here, we present comprehensive descriptions of No. mckinleyi and No. graffami, the latter of which represents the most complete therizinosaurid skeleton known to date. We amend previous preliminary descriptions of No. mckinleyi and No. graffami based on these new data and modify previous character states based on an in-depth morphological analysis. Additionally, we review the depositional history of both specimens of Nothronychus and compare their taphonomic modes. We demonstrate that the species were not only separated geographically, but also temporally. Based on ammonoid biozones, the species appear to have been separated by at least 1.5 million years and up to 3 million years. We then discuss the impacts of diagenetic deformation on morphology and reevaluate potentially diagnostic characters in light of these new data. For example, the ulna of No. mckinleyi is curved whereas the ulna of No. graffami was considered straight, a character originally separating the two species. However, here we present the difference as much more likely related to diagenetic compression in No. graffami rather than as a true biologic difference. Finally, we include copies of three-dimensional surface scans of all major bones for both taxa for reference.}, number={6}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Hedrick, Brandon P. and Zanno, Lindsay E. and Wolfe, Douglas G. and Dodson, Peter}, editor={Mihlbachler, Matthew C.Editor}, year={2015}, month={Jun}, pages={e0129449} }
 @article{gates_zanno_makovicky_2015, title={Theropod teeth from the upper Maastrichtian Hell Creek Formation "Sue" Quarry: New morphotypes and faunal comparisons}, volume={60}, number={1}, journal={Acta Palaeontologica Polonica}, author={Gates, T. A. and Zanno, L. E. and Makovicky, P. J.}, year={2015}, pages={131–139} }
 @article{lautenschlager_witmer_altangerel_zanno_rayfield_2014, title={Cranial anatomy of ​Erlikosaurus andrewsi (​Dinosauria: Therizinosauria): new insights based on digital reconstruction}, volume={34}, ISSN={["1937-2809"]}, DOI={10.1080/02724634.2014.874529}, abstractNote={ABSTRACT 
 The skull of Erlikosaurus andrewsi from the Upper Cretaceous Baishin Tsav locality of Mongolia represents the only known three-dimensionally preserved and nearly complete skull of a therizinosaurian. Computed tomographic (CT) scanning of the original specimen and three-dimensional visualization techniques allow the cranial skeleton to be digitally prepared, disarticulated, and restored. Here, we present a detailed description of the restored skull morphology and the individual cranial elements, including visualization of the internal neurovascular and pneumatic structures. Information gained from this study is used in a revised and emended diagnosis for E. andrewsi. A reappraisal of the evolutionary and functional changes in the cranial skeleton as provided by this study supports prior proposals that a keratinous sheath or rhamphotheca was developed early in the evolution of Therizinosauria. Paralleled by the reduction of functional and replacement teeth, this development indicates a shift in the manner of food processing/procurement at the tip of the snout. Extensive pneumatization of the braincase, most evidently developed in E. andrewsi in comparison with other known therizinosaurians, appears to have led to a reduction of the adductor musculature and thus the potential bite force in derived therizinosaurians. In addition, the application of digital data, as presented in this study, introduces a novel way to document fossil data that will allow for morphological and anatomical data to be made widely accessible.}, number={6}, journal={Journal of Vertebrate Paleontology}, author={Lautenschlager, S. and Witmer, L.M. and Altangerel, P. and Zanno, L.E. and Rayfield, E.J.}, year={2014}, month={Sep}, pages={1263–1291} }
 @inbook{zanno_loewen_farke_kim_claessens_mcgarrity_2013, place={Bloomington}, title={Late Cretaceous theropod dinosaurs of southern Utah}, booktitle={At the Top of the Grand Staircase: the Late Cretaceous of southern Utah}, publisher={Indiana University Press}, author={Zanno, L.E. and Loewen, M.A. and Farke, A.A. and Kim, G.-S. and Claessens, L.P.A.M. and McGarrity, CTA}, editor={Titus, A. and Loewen, M.A.Editors}, year={2013}, pages={504–525} }
 @article{zanno_makovicky_2013, title={Neovenatorid theropods are apex predators in the Late Cretaceous of North America}, volume={4}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/ncomms3827}, DOI={10.1038/ncomms3827}, abstractNote={Allosauroid theropods were a diverse and widespread radiation of Jurassic-Cretaceous megapredators. Achieving some of the largest body sizes among theropod dinosaurs, these colossal hunters dominated terrestrial ecosystems until a faunal turnover redefined apex predator guild occupancy during the final 20 million years of the Cretaceous. Here we describe a giant new species of allosauroid--Siats meekerorum gen. et sp. nov.--providing the first evidence for the cosmopolitan clade Neovenatoridae in North America. Siats is the youngest allosauroid yet discovered from the continent and demonstrates that the clade endured there into the Late Cretaceous. The discovery provides new evidence for ecologic sympatry of large allosauroids and small-bodied tyrannosauroids. These data support the hypothesis that extinction of Allosauroidea in terrestrial ecosystems of North America permitted ecological release of tyrannosauroids, which went on to dominate end-Cretaceous food webs.}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Zanno, Lindsay E. and Makovicky, Peter J.}, year={2013}, month={Nov} }
 @article{zanno_makovicky_2013, title={No evidence for directional evolution of body mass in herbivorous theropod dinosaurs}, volume={280}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2012.2526}, DOI={10.1098/rspb.2012.2526}, abstractNote={The correlation between large body size and digestive efficiency has been hypothesized to have driven trends of increasing mass in herbivorous clades by means of directional selection. Yet, to date, few studies have investigated this relationship from a phylogenetic perspective, and none, to our knowledge, with regard to trophic shifts. Here, we reconstruct body mass in the three major subclades of non-avian theropod dinosaurs whose ecomorphology is correlated with extrinsic evidence of at least facultative herbivory in the fossil record—all of which also achieve relative gigantism (more than 3000 kg). Ordinary least-squares regressions on natural log-transformed mean mass recover significant correlations between increasing mass and geological time. However, tests for directional evolution in body mass find no support for a phylogenetic trend, instead favouring passive models of trait evolution. Cross-correlation of sympatric taxa from five localities in Asia reveals that environmental influences such as differential habitat sampling and/or taphonomic filtering affect the preserved record of dinosaurian body mass in the Cretaceous. Our results are congruent with studies documenting that behavioural and/or ecological factors may mitigate the benefit of increasing mass in extant taxa, and suggest that the hypothesis can be extrapolated to herbivorous lineages across geological time scales.}, number={1751}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Zanno, Lindsay E. and Makovicky, Peter J.}, year={2013}, month={Jan}, pages={20122526} }
 @article{gates_zanno_makovicky_2013, title={Theropod teeth from the upper Maastrichtian Hell Creek Formation “Sue” Quarry: new morphotypes and faunal comparisons}, volume={60}, DOI={http://dx.doi.org/10.4202/app.2012.0145}, abstractNote={Isolated teeth from vertebrate microfossil localities often provide unique information on the biodiversity of ancient ecosystems that might otherwise remain unrecognized. Microfossil sampling is a particularly valuable tool for documenting taxa that are poorly represented in macrofossil surveys due to small body size, fragile skeletal structure, or relatively low ecosystem abundance. Because biodiversity patterns in the late Maastrichtian of North American are the primary data for a broad array of studies regarding non-avian dinosaur extinction in the terminal Cretaceous, intensive sampling on multiple scales is critical to understanding the nature of this event. We address theropod biodiversity in the Maastrichtian by examining teeth collected from the Hell Creek Formation locality that yielded FMNH PR 2081 (the Tyrannosaurus rex specimen “Sue”). Eight morphotypes (three previously undocumented) are identified in the sample, representing Tyrannosauridae, Dromaeosauridae, Troodontidae, and Avialae. Notice...}, number={1}, journal={Acta Palaeontologica Polonica}, publisher={Acta Paleontol Pol}, author={Gates, T.A. and Zanno, L.E. and Makovicky, P.J.}, year={2013}, pages={131–139} }
 @article{gates_prieto-marquez_zanno_2012, title={Mountain building triggered late Cretaceous North American megaherbivore dinosaur radiation}, volume={7}, number={8}, journal={PLoS One}, author={Gates, T. A. and Prieto-Marquez, A. and Zanno, L. E.}, year={2012} }
 @article{lautenschlager_rayfield_altangerel_zanno_witmer_2012, title={The Endocranial Anatomy of Therizinosauria and Its Implications for Sensory and Cognitive Function}, volume={7}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0052289}, DOI={10.1371/journal.pone.0052289}, abstractNote={Background Therizinosauria is one of the most enigmatic and peculiar clades among theropod dinosaurs, exhibiting an unusual suite of characters, such as lanceolate teeth, a rostral rhamphotheca, long manual claws, and a wide, opisthopubic pelvis. This specialized anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory. Despite a large number of discoveries in recent years, the fossil record for Therizinosauria is still relatively poor, and cranial remains are particularly rare. Methodology/Principal Findings Based on computed tomographic (CT) scanning of the nearly complete and articulated skull of Erlikosaurus andrewsi, as well as partial braincases of two other therizinosaurian taxa, the endocranial anatomy is reconstructed and described. The wider phylogenetic range of the described specimens permits the evaluation of sensory and cognitive capabilities of Therizinosauria in an evolutionary context. The endocranial anatomy reveals a mosaic of plesiomorphic and derived characters in therizinosaurians. The anatomy of the olfactory apparatus and the endosseous labyrinth suggests that olfaction, hearing, and equilibrium were well-developed in therizinosaurians and might have affected or benefited from an enlarged telencephalon. Conclusion/Significance This study presents the first appraisal of the evolution of endocranial anatomy and sensory adaptations in Therizinosauria. Despite their phylogenetically basal position among maniraptoran dinosaurs, therizinosaurians had developed the neural pathways for a well developed sensory repertoire. In particular olfaction and hearing may have played an important role in foraging, predator evasion, and/or social complexity.}, number={12}, journal={PLoS ONE}, publisher={Public Library of Science (PLoS)}, author={Lautenschlager, Stephan and Rayfield, Emily J. and Altangerel, Perle and Zanno, Lindsay E. and Witmer, Lawrence M.}, editor={Butler, Richard J.Editor}, year={2012}, month={Dec}, pages={e52289} }
 @article{zanno_varricchio_o'connor_titus_knell_2011, title={A New Troodontid Theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America}, volume={6}, ISSN={1932-6203}, url={http://dx.doi.org/10.1371/journal.pone.0024487}, DOI={10.1371/journal.pone.0024487}, abstractNote={Background Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species—Troodon formosus—presently known from substantial skeletal remains. Methodology/Principal Findings Here we report a gracile new troodontid theropod—Talos sampsoni gen. et sp. nov.—from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes. Conclusion/Significance Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and/or intraspecific combat for the second pedal digit, and supporting trackway evidence indicating a minimal role in weight bearing.}, number={9}, journal={PLoS ONE}, publisher={Public Library of Science (PLoS)}, author={Zanno, Lindsay E. and Varricchio, David J. and O'Connor, Patrick M. and Titus, Alan L. and Knell, Michael J.}, editor={Lalueza-Fox, CarlesEditor}, year={2011}, month={Sep}, pages={e24487} }
 @article{smith_zanno_sanders_deblieux_kirkland_2011, title={New information on the braincase of the North American therizinosaurian (Theropoda, Maniraptora) Falcarius utahensis}, volume={31}, DOI={10.1080/02724634.2011.549442}, abstractNote={ABSTRACT 
 Many disarticulated bones from multiple individuals of a primitive therizinosaurian, referred to Falcarius utahensis, were found in the paucispecific Crystal Geyser bonebed in the Lower Cretaceous Cedar Mountain Formation of eastern Utah. To date, more than 2000 specimens from this species have been excavated. Included in this collection are two partial braincases, one of which is designated the holotype. Here we describe the braincase morphology of Falcarius utahensis. These specimens help establish the primitive cranial condition for the Therizinosauria and further substantiate intraspecific and contralateral braincase pneumatic variation in theropods. When combined with new observations on the cranial remains of the therizinosaurid Nothronychus mckinleyi derived from computed tomographic (CT) scans, the braincase morphology of Falcarius clarifies several evolutionary trends within the Therizinosauria and establishes a suite of synapomorphies for the Therizinosauridae. Trends within the clade include increased basicranial pneumatization (the development of a basisphenoid bulla and loss of external subcondylar recesses), anterior deflection of the supraoccipital, and the reduction of points of origin of the craniocervical musculature, associated with the loss of discrete basipterygoid processes, probably due to incorporation of these structures into the expanded hyperpneumatic bone. Finally, CT scans reveal a complete, nearly avian, inner ear with bird-like semicircular canals and a long cochlea indicating broad frequency discrimination.}, number={2}, journal={Journal of Vertebrate Paleontology}, author={Smith, D.K. and Zanno, L.E. and Sanders, R.K. and DeBlieux, D.D. and Kirkland, J.I.}, year={2011}, pages={387–404} }
 @article{zanno_makovicky_2011, title={On the earliest record of Cretaceous tyrannosauroids in western North America: implications for an Early Cretaceous Laurasian interchange event}, volume={23}, ISSN={0891-2963 1029-2381}, url={http://dx.doi.org/10.1080/08912963.2010.543952}, DOI={10.1080/08912963.2010.543952}, abstractNote={The sudden appearance of Asian dinosaur clades within Lower Cretaceous strata of western North America has long been recognised as a biotic dispersion event related to initial establishment of a Beringian land bridge. To date, uncertainty exists regarding the timing of the Early Cretaceous Laurasian interchange event (EKLInE) and the pattern of associated biotic dispersal. Here, we report a tyrannosauroid premaxillary tooth (FMNH PR 2750) from the Cloverly Formation, Wyoming, USA, that pushes back the earliest Cretaceous record of the clade in North America. Although fragmentary, the tooth is consistent with mounting evidence for a pre-108 Ma initiation of EKLInE and earliest Albian emplacement of Beringia. Previous authors have considered the Aptian/Albian of western North America a depauperate dinosaur fauna, characterised by regional extinction and diversity decline. Documentation of Albian tyrannosauroids in the region indicates a more dynamic ecosystem than previously appreciated and marks an early start to faunal mixing between immigrant and endemic dinosaur clades. Finally, we find that the enamel microstructure of FMNH PR 2750 conforms to the morphotype of tyrannosaurids, yet exhibits poor columnar differentiation. This morphology bolsters prior interpretations on the phylogenetic utility of enamel microstructure and suggests a trend of increasing enamel complexity within Tyrannosauroidea.}, number={4}, journal={Historical Biology}, publisher={Informa UK Limited}, author={Zanno, Lindsay E. and Makovicky, Peter J.}, year={2011}, month={Dec}, pages={317–325} }
 @book{makovicky_zanno_2011, place={Berkeley}, title={Theropod diversity and the refinement of avian characteristics}, journal={Living Dinosaurs: The Evolutionary History of Modern Birds.}, publisher={University of California Press}, author={Makovicky, P.J. and Zanno, L.E.}, editor={Dyke, G. and Kaiser, G.Editors}, year={2011}, pages={9–29} }
 @article{zanno_2010, title={A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora)}, volume={8}, DOI={10.1080/14772019.2010.488045}, abstractNote={Therizinosaurians are among the most poorly understood dinosaurs. Their unusual morphology and fragmentary fossil record has precluded a synthetic understanding of the group since their remains were first discovered over 60 years ago. Although the clade was recently substantiated as a monophyletic group of maniraptoran theropods, little foundational work has been conducted at the species level. A recent plethora of therizinosaurian discoveries – including the most complete primitive and derived members recovered to date – permits an alpha taxonomic and phylogenetic re-evaluation of the clade. The phylogenetic analysis presented is the most comprehensive yet conducted for Therizinosauria, and provides a foundation for scrutinizing previous definitions of Therizinosauria, Therizinosauroidea and Therizinosauridae. Here, support is provided for the maintenance of all three taxa; however, Therizinosauria is redefined and Falcarius is excluded from Therizinosauroidea. In addition, the previously described therizinosauroids, Beipiaosaurus, Enigmosaurus, Suzhousaurus, Segnosaurus and Therizinosaurus, are rediagnosed and photodocumented. In contrast to other analyses, the ingroup topology recovered in this study suggests intermediate (therizinosauroid) status for Neimongosaurus, Erliansaurus and Enigmosaurus (based on relatively primitive pelvic morphology), despite the derived forelimb anatomy evident in the former two taxa. Here, the large-bodied taxa Nothronychus and Nanshiungosaurus brevispinus are recovered as therizinosaurids. This discrepancy indicates a relatively complex pattern of mosaic evolution, which may ultimately be found to correlate with body-size trends in the clade. This work also reviews the chronostratigraphic and biogeographic distribution of therizinosaurian taxa and putatively referred elements and finds no compelling evidence of the clade outside of Asia and North America, nor for the referral of therizinosaurian materials from Kazakhstan to cf. Neimongosaurus. Time calibration of ingroup relationships indicates a pre-Turonian dispersal event is needed to account for the presence of therizinosaurids in the Late Cretaceous of North America and Asia; this conclusion supports previous hypotheses of a Laurasian faunal interchange event during the Albian.}, number={4}, journal={Journal of Systematic Palaeontology}, author={Zanno, L.E.}, year={2010}, pages={503–543} }
 @article{gates_sampson_zanno_roberts_eaton_nydam_hutchison_smith_loewen_getty_et al._2010, title={Biogeography of terrestrial and freshwater vertebrates from the late Cretaceous (Campanian) Western Interior of North America}, volume={291}, ISSN={0031-0182}, url={http://dx.doi.org/10.1016/j.palaeo.2010.03.008}, DOI={10.1016/j.palaeo.2010.03.008}, abstractNote={Previous biogeographic studies of late Cretaceous (late Campanian) vertebrate faunas in the Western Interior Basin (WIB) of North America have suggested the presence of faunal and floral provincialism, characterized by distinct northern and southern ‘biomes.’ However, the “provincialism hypothesis” has been questioned based largely on the contention that the investigated faunas were recovered from a series of diachronous, time-transgressive deposits, and are therefore non-correlative. Extensive work in several fossiliferous units of late Campanian age, including the Dinosaur Park, Judith River, Two Medicine, Kaiparowits, Fruitland/Kirtland, and Aguja formations, has greatly increased understanding of WIB vertebrate faunas and their chronostratigraphic relationships. Here updated and greatly expanded faunal and chronostratigraphic datasets are utilized to undertake an extensive biogeographic analysis of these six terrestrial fossiliferous formations within the WIB of North America. Quantitative biogeographic comparisons of the formations and their constituent faunas are conducted using four statistical methods: Analysis of Similarity, Q-mode cluster analysis, Parsimony Analysis of Endemicity, and Correspondence Analysis. The results of this study provide strong support for highly divergent faunas in northern and southern regions of the WIB, with a latitudinal faunal gradient as an interface. Yet the nature of the interface between these faunas remains unclear, with possibilities including: 1) two or more discrete provinces separated by a zone (or zones) of faunal mixing; and 2) a continuous latitudinal gradient or cline, with no discrete zones of endemism. Lacking evidence of any physiographic barrier to north–south dispersal, climatic variation within the WIB is regarded as the most likely explanation for the overarching biogeographic patterns observed for late Campanian vertebrate taxa.}, number={3-4}, journal={Palaeogeography, Palaeoclimatology, Palaeoecology}, publisher={Elsevier BV}, author={Gates, T.A. and Sampson, S.D. and Zanno, L.E. and Roberts, E.M. and Eaton, J.G. and Nydam, R.L. and Hutchison, J.H. and Smith, J.A. and Loewen, M.A. and Getty, M.A. and et al.}, year={2010}, month={May}, pages={371–387} }
 @inbook{sampson_gates_roberts_getty_zanno_loewen_smith_lund_sertich_titus_2010, place={Washington, DC}, title={Grand Staircase-Escalante National Monument: a new and critical window into the world of dinosaurs}, volume={2}, booktitle={Learning from the land : Grand Staircase-Escalante National Monument Science Symposium Proceedings}, publisher={Bureau of Land Management}, author={Sampson, S.D. and Gates, T.A. and Roberts, E.M. and Getty, M.A. and Zanno, L.E. and Loewen, M.A. and Smith, J.A. and Lund, E.K. and Sertich, J. and Titus, A.L.}, year={2010}, pages={171–188} }
 @article{zanno_makovicky_2010, title={Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution}, volume={108}, ISSN={0027-8424 1091-6490}, url={http://dx.doi.org/10.1073/pnas.1011924108}, DOI={10.1073/pnas.1011924108}, abstractNote={Interpreting key ecological parameters, such as diet, of extinct organisms without the benefit of direct observation or explicit fossil evidence poses a formidable challenge for paleobiological studies. To date, dietary categorizations of extinct taxa are largely generated by means of modern analogs; however, for many species the method is subject to considerable ambiguity. Here we present a refined approach for assessing trophic habits in fossil taxa and apply the method to coelurosaurian dinosaurs—a clade for which diet is particularly controversial. Our findings detect 21 morphological features that exhibit statistically significant correlations with extrinsic fossil evidence of coelurosaurian herbivory, such as stomach contents and a gastric mill. These traits represent quantitative, extrinsically founded proxies for identifying herbivorous ecomorphology in fossils and are robust despite uncertainty in phylogenetic relationships among major coelurosaurian subclades. The distribution of these features suggests that herbivory was widespread among coelurosaurians, with six major subclades displaying morphological evidence of the diet, and that contrary to previous thought, hypercarnivory was relatively rare and potentially secondarily derived. Given the potential for repeated, independent evolution of herbivory in Coelurosauria, we also test for repetitive patterns in the appearance of herbivorous traits within sublineages using rank concordance analysis. We find evidence for a common succession of increasing specialization to herbivory in the subclades Ornithomimosauria and Oviraptorosauria, perhaps underlain by intrinsic functional and/or developmental constraints, as well as evidence indicating that the early evolution of a beak in coelurosaurians correlates with an herbivorous diet.}, number={1}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Zanno, L. E. and Makovicky, P. J.}, year={2010}, month={Dec}, pages={232–237} }
 @article{zanno_2010, title={Osteology of Falcarius utahensis (Dinosauria: Theropoda): characterizing the anatomy of basal therizinosaurs}, volume={158}, DOI={10.1111/j.1096-3642.2009.00464.x}, abstractNote={Falcarius utahensis, from the lower Yellow Cat Member of the Cedar Mountain Formation, represents the most complete and morphologically primitive therizinosaur yet discovered. Since initial publication, only the braincase, pectoral girdle, and forelimb of this phylogenetically important taxon have been subject to detailed investigation. This work completes the description of skeletal material prepared from the Crystal Geyser Quarry subsequent to the first five years of excavation – including elements of the skull, axial column, pelvis, and hind limb of this phylogenetically critical theropod – and presents an emended and significantly expanded diagnosis. Results of this study reveal a significant degree of morphological disparity between Falcarius utahensis and the evidently coeval primitive therizinosaur Beipiaosaurus inexpectus from the Yixian Formation, People's Republic of China and help characterize morphological transformations occurring in the therizinosaur lineage that are of phylogenetic significance, particularly with regard to the highly derived presacral axial column. Finally, Falcarius documents that marked heterodonty – characterized by elongate, incisiform rostral teeth – is present in basal therizinosaurs and oviraptorosaurs (i.e. Incisivosaurus gauthieri, Protarchaeopteryx robusta), and either represents a synapomorphy or symplesiomorphy for these groups or an early phase in the convergent progression toward rostral endentulism. Nonetheless, heterodonty suggests that diet was a primary factor in the early evolution of both clades. 
 
 
 
© 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158, 196–230.}, number={1}, journal={Zoological Journal of the Linnean Society}, author={Zanno, L.E.}, year={2010}, month={Jan}, pages={196–230} }
 @inbook{zanno_wiersma_loewen_sampson_getty_2010, place={Washington, DC}, title={Preliminary report on the theropod dinosaur fauna of the late Campanian Kaiparowits Formation, Grand Staircase-Escalante National Monument, Utah}, volume={2}, booktitle={Learning from the land : Grand Staircase-Escalante National Monument Science Symposium Proceedings}, publisher={Bureau of Land Management}, author={Zanno, L.E. and Wiersma, J.P. and Loewen, M.A. and Sampson, S.D. and Getty, M.A.}, year={2010}, pages={204–217} }
 @article{zanno_gillette_albright_titus_2009, title={A new North American therizinosaurid and the role of herbivory in “predatory" dinosaur evolution.}, volume={276}, DOI={10.1098/rspb.2009.1029}, abstractNote={Historically, ecomorphological inferences regarding theropod (i.e. ‘predatory’) dinosaurs were guided by an assumption that they were singularly hypercarnivorous. A recent plethora of maniraptoran discoveries has produced evidence challenging this notion. Here, we report on a new species of maniraptoran theropod, Nothronychus graffami sp. nov. Relative completeness of this specimen permits a phylogenetic reassessment of Therizinosauria—the theropod clade exhibiting the most substantial anatomical evidence of herbivory. In the most comprehensive phylogenetic study of the clade conducted to date, we recover Therizinosauria as the basalmost maniraptoran lineage. Using concentrated changes tests, we present evidence for correlated character evolution among herbivorous and hypercarnivorous taxa and propose ecomorphological indicators for future interpretations of diet among maniraptoran clades. Maximum parsimony optimizations of character evolution within our study indicate an ancestral origin for dietary plasticity and facultative herbivory (omnivory) within the clade. These findings suggest that hypercarnivory in paravian dinosaurs is a secondarily derived dietary specialization and provide a potential mechanism for the invasion of novel morpho- and ecospace early in coelurosaurian evolution—the loss of obligate carnivory and origin of dietary opportunism.}, number={1672}, journal={Proceedings of the Royal Society B: Biological Sciences}, author={Zanno, L.E. and Gillette, D.D. and Albright, L.B. and Titus, A.L.}, year={2009}, month={Oct}, pages={3505–3511} }
 @article{gates_sampson_de jesús_zanno_eberth_hernandez-rivera_martínez_kirkland_2007, title={Velafrons coahuilensis, a new lambeosaurine hadrosaurid (Dinosauria: Ornithopoda) from the late Campanian Cerro del Pueblo Formation, Coahuila, Mexico}, volume={27}, ISSN={0272-4634 1937-2809}, url={http://dx.doi.org/10.1671/0272-4634(2007)27[917:vcanlh]2.0.co;2}, DOI={10.1671/0272-4634(2007)27[917:vcanlh]2.0.co;2}, abstractNote={Abstract A new lambeosaurine hadrosaurid, Velafrons coahuilensis, is described as the first lambeosaurine from the Cerro del Pueblo Formation of Coahuila, Mexico, and the first lambeosaurine genus to be named from North America in more than 70 years. Although the holotype specimen is a juvenile individual—as evidenced by its incomplete crest development and relative size compared to other North American lambeosaurines—ontogeny independent autapomorphies have been identified including quadrate with narrow quadratojugal notch and a postorbital with well developed, dorsally positioned squamosal process. Additionally, this taxon is unique in that the prefrontal is not dorsally deflected and anteroposteriorly expanded as in other lambeosaurine taxa of its size, but rather retains the frontal-prefrontal “clamp” present in smaller individuals of other taxa. Phylogenetic analysis places Velafrons in a polytomy with numerous other fan-crested lambeosaurines. The crest structure of Velafrons more closely resembles that of Corythosaurus and Hypacrosaurus because it possesses an anteriorly projecting nasal process over the dorsal premaxilla process. Biogeographically, Velafrons is one of three distinct hadrosaurids known from approximately 73.5 Ma—two lambeosaurines and one hadrosaurine—all restricted to the southern region of the Western Interior Basin of North America.}, number={4}, journal={Journal of Vertebrate Paleontology}, publisher={Informa UK Limited}, author={Gates, Terry A. and Sampson, Scott D. and De Jesús, Carlos R. Delgado and Zanno, Lindsay E. and Eberth, David and Hernandez-Rivera, René and Martínez, Martha C. Aguillón and Kirkland, James I.}, year={2007}, month={Dec}, pages={917–930} }
 @article{zanno_2006, title={The pectoral girdle and forelimb of the primitive therizinosauroidFalcarius Utahensis(Theropoda, Maniraptora): analyzing evolutionary trends within Therizinosauroidea}, volume={26}, ISSN={0272-4634 1937-2809}, url={http://dx.doi.org/10.1671/0272-4634(2006)26[636:tpgafo]2.0.co;2}, DOI={10.1671/0272-4634(2006)26[636:tpgafo]2.0.co;2}, abstractNote={Abstract The recent discovery of a dense, paucispecific bonebed from the Early Cretaceous Cedar Mountain Formation, central Utah, has yielded new information on the morphology and evolution of therizinosaurs. Detailed description of the pectoral girdle and forelimb of Falcarius utahensis—the predominant taxon recovered from this site—provides the basis for a species-level, phylogenetic investigation of this enigmatic group. The analysis, consisting of 32 characters arrayed among 13 taxa, supports previous assertions that Falcarius represents the basal-most known member of the clade. The analysis further supports a monophyletic Therizinosauroidea on the basis of seven unambiguous synapomorphies of the pectoral girdle and forelimb. Contrary to previous hypotheses, analysis of the pectoral girdle and forelimb suggests that Therizinosauridae is more appropriately defined as a derived clade including Nothronychus, Erlicosaurus, Neimongosaurus, Therizinosaurus, and Segnosaurus. Equally strong support is recovered for a clade containing these five genera plus “Alectrosaurus” and Erliansaurus. The morphology of primitive therizinosauroids—characterized by Falcarius, Beipiaosaurus, and Alxasaurus—suggests that Early Cretaceous taxa already exhibited the beginnings of a trend toward increased robustness and altered range of motion of the pectoral girdle and forelimb. Derived therizinosaurs exhibit an amplification of these evolutionary trends as well as increased dorsal reach, increased wrist flexibility, and severe reduction in manual digit length. The functional reorganization of the pectoral girdle and forelimb throughout the evolutionary history of therizinosaurs can be reasonably attributed to a shift from obligatory predation to a novel paleoecological role that reached its pinnacle in derived Late Cretaceous members.}, number={3}, journal={Journal of Vertebrate Paleontology}, publisher={Informa UK Limited}, author={Zanno, Lindsay E.}, year={2006}, month={Sep}, pages={636–650} }
 @article{zanno_sampson_2005, title={A new Oviraptorosaur (Theropoda, Maniraptora) from the Late Cretaceous (Campanian) of Utah}, volume={25}, ISSN={0272-4634 1937-2809}, url={http://dx.doi.org/10.1671/0272-4634(2005)025[0897:anotmf]2.0.co;2}, DOI={10.1671/0272-4634(2005)025[0897:anotmf]2.0.co;2}, abstractNote={Abstract Recent field expeditions to Upper Cretaceous deposits within Grand Staircase-Escalante National Monument, southern Utah, have revealed a diverse dinosaurian fauna that includes a previously unknown oviraptorosaur theropod. Represented by a single partial specimen consisting of manal and pedal elements, this new taxon, Hagryphus giganteus, gen. et. sp. nov., is estimated to be 30–40% larger than the coeval oviraptorosaur Chirostenotes. The holotype consists of a nearly complete, articulated left manus, a partial, articulated pedal digit II, and a series of fragmentary pedal phalanges and distal metatarsals. Several autapomorphies are present in the manus, related primarily to proportional differences in metacarpals and phalanges. Previous finds of North American oviraptorosaurs have been restricted to Alberta, Montana, and South Dakota. The discovery of this new specimen from southern Utah greatly expands the known geographic distribution of these theropods, nearly doubling the previously documented range of North American oviraptorosaurs.}, number={4}, journal={Journal of Vertebrate Paleontology}, publisher={Informa UK Limited}, author={Zanno, Lindsay E. and Sampson, Scott D.}, year={2005}, month={Dec}, pages={897–904} }
 @article{kirkland_zanno_sampson_clark_deblieux_2005, title={A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah}, volume={435}, ISSN={0028-0836 1476-4687}, url={http://dx.doi.org/10.1038/nature03468}, DOI={10.1038/nature03468}, abstractNote={Therizinosauroids are an enigmatic group of dinosaurs known mostly from the Cretaceous period of Asia, whose derived members are characterized by elongate necks, laterally expanded pelves, small, leaf-shaped teeth, edentulous rostra and mandibular symphyses that probably bore keratinized beaks. Although more than a dozen therizinosauroid taxa are known, their relationships within Dinosauria have remained controversial because of fragmentary remains and an unusual suite of characters. The recently discovered 'feathered' therizinosauroid Beipiaosaurus from the Early Cretaceous of China helped to clarify the theropod affinities of the group. However, Beipiaosaurus is also poorly represented. Here we describe a new, primitive therizinosauroid from an extensive paucispecific bonebed at the base of the Cedar Mountain Formation (Early Cretaceous) of east-central Utah. This new taxon represents the most complete and most basal therizinosauroid yet discovered. Phylogenetic analysis of coelurosaurian theropods incorporating this taxon places it at the base of the clade Therizinosauroiden, indicating that this species documents the earliest known stage in the poorly understood transition from carnivory to herbivory within Therizinosauroidea. The taxon provides the first documentation, to our knowledge, of therizinosauroids in North America during the Early Cretaceous.}, number={7038}, journal={Nature}, publisher={Springer Nature}, author={Kirkland, James I. and Zanno, Lindsay E. and Sampson, Scott D. and Clark, James M. and DeBlieux, Donald D.}, year={2005}, month={May}, pages={84–87} }
 @inbook{zanno_heckert_kryzyzanowski_lucas_2002, place={Albuquerque, New Mexico}, series={New Mexico Museum of Natural History & Science Bulletin}, title={Diminutive Metoposaurid skulls from the Upper Triassic Blue Hills (Adamanian: latest Carnian) of Arizona}, booktitle={Upper Triassic Stratigraphy and Paleontology}, publisher={New Mexico Museum of Natural History and Science Bulletin}, author={Zanno, L.E. and Heckert, A.B. and Kryzyzanowski, S.E. and Lucas, S.G.}, editor={Heckert, A.B. and Lucas, S.G.Editors}, year={2002}, pages={121–125}, collection={New Mexico Museum of Natural History & Science Bulletin} }