A vehicle driving in Zimbabwe, viewed from above

A bird embryo viewed through confocal microscopy

A colorful image of fossil bone microstructure, viewed through a microscope

We Explore the History and Evolution of Vertebrate Form

Research

The paleontological record is the only direct window into the history of life. Conversely, it is through developmental biology that the specific mechanisms driving morphological evolution can be determined.

In our lab, situated within the Department of Geosciences at Princeton University, we seek to unite these disparate sources of data to form a single cohesive story of how animal form evolves. By placing fossils into a broad quantitative, geological, and phylogenetic context we can then use techniques gleaned from embryology to interrogate the mechanisms by which major transitions and the origin of major groups have occurred, taking these insights back into the rock record.

A man brushing sediment away from a fossilized bone

Vertebrate animals are the most morphologically complex organisms, and so are an excellent system to study the evolution of form and anatomical novelty. Further, morphology is the most fundamental level of data in vertebrate paleontology, because it is through interpretations of form that taxa are identified, creating the basis for broad evolutionary inferences.

We are active in characterizing the patterns and processes by which vertebrate form has evolved, placing these data into comparative, quantitative frameworks to better understand the history of vertebrate life.

Growth and development are universal biotic processes, and therefore play a critical role in evolution: a given individual is only the shape and size that it is because of the developmental processes it has undergone.

We therefore explore developmental processes in many forms: postnatal ontogeny in extant and extinct species, the record of growth contained in the microstructure of bony tissues, and the investigation of embryonic tissues and their corresponding gene expression patterns using cutting-edge imaging and next-gen sequencing techniques. We place all these data into a broad qualitative and quantitative framework to better constrain the processes underlying the evolutionary history of vertebrates.

The hips and hindlimb of an Alligator embryo, viewed through a confocal microscope

Diversity, disparity, and abundance are not evenly distributed between vertebrate groups—there are certain major clades that contain thousands of species, a breathtaking array of forms, enormous ranges in body size, and geographic breadths that span hemispheres.

In our lab, we are interested in interrogating the origin of these major clades: In what environmental and ecological context did major clades originate? How did they rise to their eventual status as ecologically important groups, and what factors might have contributed to this success? What processes and patterns underlie the evolution of morphological novelties in these groups?

A man holding a fossil bone above a shelf full of fossils

Our new laboratory will be in Princeton’s Environmental Science neighborhood, with a state-of-the-art paleontological lab space, molding, casting, and paleohistology facilities, and high-grade microscopy resources. Complementing this is our molecular biology/embryology laboratory with a -20C environmental room, a cell/tissue culture room, and a dedicated area for experimental embryology. The confocal micropes, lightsheet microscopes, and micro-CT scanning facilities at the Princeton Imaging & Analysis Center combined with our high-performance computer lab and 3D scanning/printing equipment, empower us to explore vertebrate form throughout development and Earth history.

A computer generated image of a laboratory

Fieldwork

To pursue our scientific interests and contribute to natural history collections, we are active in conducting hypothesis-driven fieldwork throughout the world. The vertebrate fossil record is notoriously scant, so increasing our sampling of life’s history is paramount: every fossil we collect has the potential to drive the field forward.
Our field program is primarily centered around the Triassic Period: it was within this environmental crucible that the vertebrate lineages that define later terrestrial ecosystems experienced their initial diversification. In addition to the field opportunities available as a broader lab, we also encourage and support student-led field projects.

Two men digging fossil bones out of sediment, viewed from above

Some of the most productive Triassic localities in the world are located in the southwestern United States, and we are active in both reopening historic localities for increased sampling with modern methods, and locating new, productive localities to better understand the co-evolution of Earth and life at this time.

Most recently, we are collaborating with the Yale Peabody Museum of Natural History to prospect, excavate, and radiometrically date several new localities in the Dockum Group of western Texas.

A red, Triassic-aged rock outcrop from the American southwest

The Late Triassic rocks of Zimbabwe contain an extensive fauna which includes the oldest dinosaurs ever found in Africa, equivalent in age to the oldest dinosaurs found anywhere in the world.

We work in active collaboration with the Natural History Museum of Zimbabwe to preserve these finds and place them into the context of the origin and rise of dinosaurs, and have other collaborative field projects in Zimbabwe exploring earlier Triassic sediments and underlying Permian-aged tetrapod assemblages.

A group photo of women and men paleontologists in Zimbabwe

The Newark Supergroup on the East Coast of the United States preserves some of the most well-dated sequences of Triassic and Early Jurassic fossils anywhere in the world, making these sediments ideal for investigating the effect of climate, geography, and paleolatitude on vertebrate evolution, origination, and extinction during the early Mesozoic.

We are particularly interested in exploring new vertebrate microsites, which have the potential to sample the smallest size classes of tetrapod faunas, giving critical insight into the vertebrate assemblages leading up to the end-Triassic mass extinction.

A scenic photograph of forested mountains in the eastern United States

The best way to test hypotheses about Triassic vertebrate origination, dispersal, and extinction resilience is to sample from extreme latitudes. The Triassic faunas of the Canadian High Arctic are critically undersampled, but a few fragmentary fossils recovered by 19th century Arctic explorers hint that monumental discoveries are waiting in these rocks.

Our first expedition to this region is planned for 2025, in collaboration with the Canadian Museum of Nature and generously funded by the Department of Geosciences at Princeton.

A scenic view from above of Bathurst Island in the Canadian Arctic

People

Chris is a paleontologist and evolutionary biologist, broadly interested in the evolution of vertebrates across deep time. Starting in Fall of 2024, he will become an assistant professor within the Department of Geosciences at Princeton University. He obtained a B.S. in Biology, Geology, and Molecular & Cellular Biology from Cedarville University before obtaining an M.S. and Ph.D. in Geosciences from Virginia Tech, followed by postdoctoral work in the Department of Earth & Planetary Sciences at Yale University.

Google Scholar

ResearchGate

If you are interested in becoming a PhD student or postdoc in the lab, please email chris.griffin[at]princeton.edu with a brief description of your background and research interests (focused on broad questions, not specific taxonomic groups), and your CV if available. We are looking for people passionate about understanding the deep history of vertebrate life. We seek to foster an inclusive professional environment, wherein every member of the lab is respected and supported.

Publications

Barta, D., C. T. Griffin, M. A. Norell. 2022. Osteohistology of a Triassic dinosaur population reveals highly variable growth trajectories typified early dinosaur ontogeny. Scientific Reports 12: 17321.

Egawa, S., C. T. Griffin, P. Bishop, R. Pintore, H. P. Tsai, J. F. Botelho, D. Smith-Paredes, S. Kuratani, M. Norell, S. Nesbitt, J. Hutchinson, B.-A. Bhullar. 2022. The dinosaurian femoral experienced a morphogenetic shift from torsion to growth along the avian stem. Proceedings of the Royal Society B: Biological Sciences 289: 20220740.

Griffin, C. T., B. M. Wynd, D. Munyikwa, T. J. Broderick, M. Zondo, S. Tolan, M. C. Langer, S. J. Nesbitt, H. R. Taruvinga. 2022. Africa’s oldest dinosaurs reveal early suppression of dinosaur distribution. Nature 609: 313–319.

Griffin, C. T., J. F. Botelho, M. Hanson, M. Fabbri, D. Smith-Paredes, R. M. Carney, M. A. Norell, S. Egawa, S. M. Gatesy, T. B. Rowe, R. M. Elsey, S. J. Nesbitt, B.-A. S. Bhullar. 2022. The developing bird pelvis passes through ancestral dinosaurian conditions. Nature 608: 346–352.

Griffin, C. T., M.R. Stocker, C. Colleary, C. M. Stefanic, E. J. Lessner, M. Riegler, K. Formoso, K. Koeller, S. J. Nesbitt. 2021. Assessing ontogenetic maturity in extinct saurian reptiles. Biological Reviews 96: 470–525.

Griffin, C. T., and S. J. Nesbitt. 2020. Does the maximum body size of theropods increase across the Triassic–Jurassic boundary? Integrating ontogeny, phylogeny, and body size. The Anatomical Record 303: 1158–1169.

Griffin, C. T. 2019. Large neotheropods from the Upper Triassic of North America and the early evolution of large theropod body sizes. Journal of Paleontology 93: 1010–1030.

Griffin, C. T. and K. D. Angielczyk. 2019. The evolution of the dicynodont sacrum: constraint and innovation in the synapsid axial column. Paleobiology 45: 201–220.

Griffin, C. T., L. S. Bano, A. H. Turner, N. D. Smith, R. B. Irmis, S. J. Nesbitt. 2019. Integrating gross morphology and bone histology to assess skeletal maturity in early dinosauromorphs: new insights from Dromomeron (Archosauria: Dinosauromorpha). PeerJ 7: e6331.

Griffin, C. T. 2018. Pathological bone tissue in a Late Triassic neotheropod fibula, with implications for the interpretation of medullary bone. New Jersey State Museum Investigations 6: 2–10.

McLain, M., D. Nelsen, K. Snyder, C. T. Griffin, B. Siviero, L. Brand, A. Chadwick. 2018. Tyrannosaur cannibalism: A case of a tooth-traced tyrannosaurid bone in the Lance Formation (Maastrichtian), Wyoming. PALAIOS 33: 164–173.

Griffin, C. T. 2018. Developmental patterns and variation among early theropods. Journal of Anatomy 232: 604–640.

Griffin, C. T., C. M. Stefanic, W. G. Parker, A. Hungerbuehler, M. Stocker. 2017. Sacral anatomy of the phytosaur Smilosuchus adamanensis, with implications for pelvic girdle evolution among Archosauriformes. Journal of Anatomy 231:886–905.

Griffin, C. T. and S. J. Nesbitt. 2016. Anomalously high variation in postnatal development is ancestral for dinosaurs but absent in birds. Proceedings of the National Academy of Sciences, USA 113: 14757-14762.

Kuruvilla, H., B. Schmidt, S. Song, M. Bhajjan, M. Merical, C. Alley, C. Griffin, D. Yoder, J. Hein, D. Kohl, C. Puffenberger, D. Petroff, E. Newcomer, K. Good, G. Heston, A. Hurtubise. 2016. Netrin-1 peptide is a chemorepellent in Tetrahymena thermophila. International Journal of Peptides 2016: 7142868.

Griffin, C. T. and S. J. Nesbitt. 2016. The histology and femoral ontogeny of the Middle Triassic (?late Anisian) dinosauriform Asilisaurus kongwe and implications for the growth of early dinosaurs. Journal of Vertebrate Paleontology 36: e1111224.