Curator/Associate Professor, Integrative Biology

His research: "My research interests are all over the place, but temporally I tend to focus on the Paleozoic, and especially the Ordovician Period. Most phyla make a relatively rapid appearance in the fossil record in the Cambrian, but it's in the mid-Ordovician when you see a big increase in diversity. During this period, the types of marine ecosystems that generally characterize much of the rest of the Paleozoic are established. But then, the Ordovician ends with the first major mass extinction. So the Ordovician is a very useful period to focus on because I'm interested in how you add diversity to ecosystems and what happens to the structure and function of those ecosystems when you take it away.

"In a recent paper in Nature, paleontologists and ecologists argue that the current anthropogenically driven mass extinction may be pushing global ecosystems towards a state shift. The late Ordovician mass extinction is interesting because it's a case where you remove huge numbers of species and genera — even families — and it doesn't make much difference in terms of the marine ecosystems. Silurian marine ecosystems look very much like those of the Ordovician! This would appear to be a really big mass extinction that actually does not result in a state shift. I find it quite interesting to compare that event with something like the Permo-Triassic extinction or what we may be heading into now."

Questions: "We can look at extinction events in terms of sheer numbers of groups that go extinct, but it's only a single dimension of diversity loss. What's interesting to me is to ask which particular things go extinct and which ones don't? How are those extinctions distributed, not just phylogenetically but ecologically? What are the determinants of extinction risk for a particular event? How do those change through time and how does that then propagate forward to determine the structure of future ecosystems?"

What he loves about research: "I really get excited about seeing fossils in the context of the rocks in the field. A drawer of museum specimens can be very interesting, but seeing those fossils in the context of the sedimentary rocks recording the environment in which they lived is a much richer experience. There's no substitute for really getting out and grappling with the taphonomic aspects - thinking about how this information is being filtered through the record, and also what the rocks are telling us about what really happened here. So field work is great both intellectually and, I won't lie, it's fun to be able to travel!

"And of course there's a real thrill when you actually figure something out - when it clicks. It's what keeps you coming back."

Selected Publications

• Zimmt, J.B., S.M. Holland, S. Finnegan, and C.R. Marshall. 2021.  Recognizing pulses of extinction from clusters of last occurrences: Palaeontology, v. 64, p. 1-20, https://doi.org/10.1111/pala.12505. Read it

• Marshall, C.R., S. Finnegan, E.C. Clites, P.A. Holroyd, N. Bonuso, C. Cortez, E. Davis, G.P. Dietl, P.S. Druckenmiller, R.C. Eng, C. Garcia, K. Estes-Smargiassi, A. Hendy, K.A. Hollis, H. Little, E.A. Nesbitt, P. Roopnarine, L. Skibinski, J. Vendetti, & L.D. White.  2018.  Quantifying the dark data in museum fossil collections as palaeontology undergoes a second digital revolution.  Biology Letters, 14: 20180431 (4 pages). Read it

• Klompmaker, A.A., and S. Finnegan.  2018.  Extreme rarity of competitive exclusion in modern and fossil marine benthic ecosystems.  Geology,  46: 723–726. Read it

• Kahanamoku, S.S., P.M. Hull, D.R. Lindberg, A.Y. Hsiang, E.C. Clites and S. Finnegan. 2018. Twelve thousand recent patellogastropods from a northeastern Pacific latitudinal gradient. Scientific Data, 5:170197. Read it

• Klompmaker, A.A., M. Kowalewski, J.W. Huntley, and S. Finnegan. 2017. Increase in predator-prey size ratios throughout the Phanerozoic history of marine ecosystems. Science, 356: 1168 - 1170.