@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={ABSTRACTAetosaurs 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, 302:1504–1515, 2019. © 2018 American Association for Anatomy}, 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} }