New position! [Posted 5/24/2022]
I’m absolutely thrilled & excited beyond words to announce that I have accepted a TT position as joint Assistant Professor of Geosciences at the University of Oklahoma and Curator of Invertebrate Paleontology at the Sam Noble Museum of Natural History!
Miniaturization during a Silurian environmental crisis generated the modern brittle star body plan [Posted 2/2/2022]
New paper alert! My colleagues and I recently described two new species of fossil brittle stars in the journal Communications Biology. Based on a combination of phylogenetic and statistical analyses, we find these temporally consecutive species document a sequence of species-to-species-level evolutionary changes that led to the origination of the modern brittle star body plan, and therefore represent a rare case of finding actual ancestor-descendant species pairs in the fossil record.
New position at the NMNH [10/16/2020]
I moved back to Washington, DC to begin a new position as a Research Paleobiologist in fossil Echinodermata at the National Museum of Natural History (Smithsonian Institution).
540-Million-Year-Old Marine Fossil Remains a Mystery [3/12/2020]
I recently co-authored a paper titled “Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella” in the journal Nature Communications.
The central focus of our paper was to better understand the evolutionary position of an important fossil species called Yanjiahella biscarpa. This species occurs in rocks dating from the early Cambrian (~540 million years old) of China, and represents one of the oldest fossils belonging to a diverse group animals called deuterostomes, (i.e., vertebrates, hemichordates, and echinoderms.). Previously, Yanjiahella was considered to be closely related to the echinoderms (e.g., starfish, sea lilies, & kin). If true, Yanjiahella would be the oldest known fossil representative of the echinoderm lineage: it’s approximately 20 million years older than all unambiguous fossil echinoderms.
However, our analysis shows was equal support for placing Yanjiahella in several different positions in the evolutionary tree of early animals. In fact, with data presently available, we find it is impossible to accurately determine Yanjiahella’s closest relatives. Nevertheless, we recognize Yanjiahella as an important fossil that almost certainly fits somewhere within the deuterostome tree of life. In conclusion, Yanjiahella is still a—very distant—relative of vertebrates that may or may not belong to the deuterostome lineage that led to starfish and sea lilies. As Vonnegut said, “so it goes.”
Undergraduate research experience at the AMNH! [1/31/2020]
Jonas with a crinoid-rich slab of Upper Ordovician limestone from Anticosti Island.
January was a fantastic month for invertebrate paleontology here at the AMNH! We welcomed Jonas Mondschein, an undergraduate from Oberlin University (Ohio), to work on a project examining patterns of morphological disparity and extinction across the Ordovician—Silurian boundary of Anticosti Island.
Working closely with myself and Dr. Melanie Hopkins, Jonas helped collect and analyze fossil crinoid data stemming from several field seasons on Anticosti Island (pun intended). Specifically, Jonas created a database of crinoid “morphotypes” that describe the morphology and stratigraphic position of crinoid columnals and attachment structures. Our preliminary analysis of these data suggests isolated crinoid stems & attachment structures can provide useful information for testing models of extinction & morphological diversification in crinoids, especially in stratigraphic sections where crinoid calyces are rarely preserved but columanals are abundant. We are planning to share our results later this year at the annual Geological Society of America meeting!
Invited lecture at The University of Chicago [3/10/2019]
I was recently invited to present a talk at the University of Chicago’s Evolutionary Morphology seminar series. During my multi-day visit, I had a spectacularly packed schedule with the pleasure of meeting researchers spanning numerous academic departments and scientific disciplines within the umbrella of the university’s Committee on Evolutionary Biology, including ecologists, evolutionary biologists, and (of course!) paleontologists in the Department of Geophysical Sciences.
On Thursday, following a full day of intellectually stimulating meetings (and grabbing a quick dinner at a delicious Thai restaurant), I presented “The dredge, the hammer, and the phylogenetic tree: reconstructing the evolution of biological diversity in crinoid echinoderms”.
I thoroughly enjoyed the opportunity to meet and interact with such a fantastic group of faculty/postdocs/students and present my research. I even managed to spend some time with fossil crinoid specimens in the Field Museum collections before my flight back to NYC! Many thanks for the invitation!
New paper published in Palaeogeography, Palaeoclimatology, Palaeoecology! [02/19/2019]
I’m delighted to share a new paper co-written with Selina R. Cole and Bill Ausich. Our paper integrates community paleoecology with phylogenetic comparative methods to study the evolution of community structure and niche distributions in crinoid echinoderms from the Brechin Lagerstätte (~450 million years ago) and other ancient ecosystems.
Here’s one of my favorite figures from our new paper. I think it nicely illustrates the relationships between skeletal morphology and species ecology in crinoids:
Below is the abstract from our paper. Check it out!
Cole, S.R., Wright, D.F., and Ausich, W.I. 2019. Phylogenetic community paleoecology of one of the earliest complex crinoid faunas (Brechin Lagerstätte, Ordovician), Palaegeography, Palaeoclimatology, Palaeoecology.
Abstract: “Integrating phylogenetic biology with paleoecology can provide a valuable context for understanding patterns of community structure and niche partitioning in ancient ecosystems. However, the lack of robust phylogenies for many fossil taxa precludes studies of this nature, particularly among marine invertebrates. Fossil Crinoidea (Echinodermata) comprise an ideal model system for phylogenetic community paleoecology for three reasons: (1) they preserve anatomical features that directly relate to feeding ecology, (2) assemblages of well-preserved specimens represent “ecological snapshots” in time, and (3) recent advances in resolving the crinoid tree of life has produced high-resolution phylogenies for Ordovician lineages. Here, we apply multivariate and phylogenetic comparative methods to investigate patterns of paleocommunity structure, niche partitioning, and ecomorphospace occupation in one of the earliest complex crinoid paleocommunities, the Brechin Lagerstätte (Upper Ordovician, Katian). Results indicate niche differences among species were determined primarily by characters related to filtration fan morphology. Filtration fan density and body size distributions support phylogenetic niche conservatism, but traits related to the size of feeding area are more labile and exhibit greater divergence than expected among closely related species. Finally, we compare changes in the shape and phylogenetic structure of niche distributions between the Brechin Lagerstätte and the Edwardsville crinoid fauna, a well-studied Mississippian (Visean) paleocommunity, to examine patterns of community change across the Early to Middle Paleozoic Crinoid Macroevolutionary Faunas.”
New website! [12/18/2018]
It took me long enough, but I’ve finally developed a website for all things related to my research, teaching, and public outreach pursuits. Like an academic CV, Baltimore Orioles baseball, and life in general: this website is a work in progress!