Randall L. Nydam, PhD

Professor & Associate Dean for Academic Affairs

Midwestern University
Arizona College of Osteopathic Medicine, Office of the Dean
Glendale Hall 313-16
19555 N 59th Ave., Glendale, AZ 85308

Office: (623) 572-3359
e-mail: rnydam@midwestern.edu


Ph.D. Vertebrate Paleontology University of Oklahoma 2000
B.A. Biology University of California, Santa Cruz 1992


Currently teaching ultrasound and heand & neck anatomy in the anatomy course taken by first year AZCOM and AZPOD students.


I am a vertebrate paleontologist studying the evolutionary history of terrestrial squamates (lizards and snakes). My primary interest is in the evolution, functional morphology, and paleobiogeography of the lizards and snakes of the Jurassic through the Paleocene. While most of my research is centered on specimens recovered from North America it also includes specimens from various other places on the globe. Currently I am working on the early evolution and distribution of snakes based on specimens from both the north and southern hemispheres including the oldest known snake fossils.

Research Gate Page

Research Projects

Early snake evolution—This project includes work on the oldest known snake fossils from both the northern and southern hemispheres. Additionally I am working on the evolution of snakes on the North American continent; the 'Coniophis problem'. This work is being done in collaboration with Dr. Michael W. Caldwell, University of Alberta.

Chamopsiids and polyglyphanodontids of the Cretaceous—This project is a continuing investigation into the evolution of a unique group of lizards only known from the Late Cretaceous of North America and some possibly related forms from the Late Cretaceous of Asia. This project is currently part of the dissertation project of Tiago Simoes, a PhD candidate at the University of Alberta for whom I am a member of the advisory committee.

The latitudinal distribution of squamates during the Late Jurassic-Late Cretaceous of North America—This ongoing project is aimed at the continuing recovery and description of squamate taxa from across North America, comparison with known faunas, and analysis of composition, diversity, and distribution of component taxa.

Selected Publications

A mid-Cretaceous embryonic-to-neonate snake in amber from Myanmar. Xing, L., M. W. Caldwell, R. Chen, R. L. Nydam, A. Palci, T. R. Simões, R. C. McKellar, M. S. Y. Lee, Y. Liu, H. Shi, K. Wang, and M. Bai. 2018.  Science Advances 4. 10.1126/sciadv.aat5042

The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps. Simões, T. R., M. W. Caldwell, M. Tałanda, M. Bernardi, A. Palci, O. Vernygora, F. Bernardini, L. Mancini, and R. L. Nydam. 2018.  Nature 557:706-709. 10.1038/s41586-018-0093-3

Reacquisition of the lower temporal bar in sexually dimorphic fossil lizards provides a rare case of convergent evolution. T. Simões, G. Funston, B. Vafaeian, R. L. Nydam, M. Doschak, and M. Caldwell. Scientific Reports 6(24087). 2016. DOI: 10.1038/srep24087

Giant Taxon-Character Matrices: Quality of Character Constructions Remains Critical Regardless of Size. T. Simões, M. Caldwell, A. Palci., and R. L. Nydam. Cladistics. 2016. DOI: 10.1111/cla.12163

Osteology, phylogeny and functional morphology of two Jurassic lizard species and the early evolution of scansoriality in geckoes. T. Simões, M. Caldwell, and R. L. Nydam, P. Jiménez-Huidobro. Zoological Journal of the Linnean Society 2016; doi: 10.1111/zoj.12487

The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution. Caldwell MW, Nydam RL, Palci A, Apesteguía S. Nature Communications 2015 Jan 27;6:5996. doi: 10.1038/ncomms6996

Lizards and snakes of the Terlingua Local Fauna (late Campanian), Aguja Formation, Texas, with comments on the distribution of paracontemporaneous squamates throughout the Western Interior of North AmericaRandall L. Nydam , Timothy B. Rowe , Richard L. Cifelli Journal of Vertebrate Paleontology Vol. 33, Iss. 5, 2013 DOI:10.1080/02724634.2013.760467

Lizards and Snakes from the Cenomanian through Campanian of Southern Utah: Filling the Gap in the Fossil Record of Squamata from the Late Cretaceous of the Western Interior of North America; Nydam, Randall L. 2013. , pp. 370-423 in, A. Titus and M. Loewen (eds) At the Top of the Grand Staircase, The Late Cretaceous of Southern Utah. Indiana University Press, Bloomington.

Reevaluation of the anatomy of the Cenomanian (Upper Cretaceous) hind-limbed marine fossil snakes PachyrhachisHaasiophis, and Eupodophis. Alessandro Palci , Michael W. Caldwell , Randall L. Nydam Journal of Vertebrate Paleontology 2013 Vol. 33, Iss. 6, DOI:10.1080/02724634.2013.779880