Published: September 9, 2017

Q&A with a Fossil Mammals Curator

Ken Angielczyk, MacArthur Curator of Paleomammalogy and Section Head, Negaunee Integrative Research Center

Paleobiologist Ken Angielczyk shares some of the unique aspects of his work. There's never a dull moment—like checking out a huge Andrewsarchus skull in the fossil mammal range! 

What does being a curator mean to you?

A big part of it is doing specimen-based research. Being at a place like the Field Museum that has extensive collections makes it easier to do that work. It also means doing research outside the museum, both in the field and in collections at other scientific institutions (which is what I do in places like Zambia and South Africa).

What are you researching?

I focus on synapsids, the group of animals that includes mammals and a variety of their extinct relatives whose fossil record stretches back about 320 million years. More specifically, I’m researching the evolution of the backbone in the synapsid ancestors of mammals. Mammals have differentiated backbones, meaning that the vertebrae, or individual bones that make up the spinal column, form different regions that are characterized by unique shapes and functions. I’m trying to learn more about when and why those different regions evolved in synapsids over time. Right now I’m in South Africa collecting data from specimens at natural history museums here. They have a great fossil record of therapsids, the advanced non-mammalian synapsids that are close to the ancestry of mammals.

How do you work with collections?

I oversee the museum’s fossil synapsid and mammal collection. The history of work that went into building the collection goes back to around the turn of the 20th century (learn more about the synapsid collection).

Many of the specimens I work with were collected by pioneers in the field of vertebrate paleontology, like Samuel Wendell Williston and Alfred Romer. It’s a great privilege to be entrusted to care for the specimens they collected while also finding new ways to look at these specimens. We’re still learning many new things from fossils collected in the 1920s and ’30s, which allows us to constantly refine our picture of synapsid evolution.

For example, CT scanning of fossils can literally let us see inside specimens in ways that were previously difficult or impossible. Likewise, comparing our specimens with those in museum collections from around the world helps us to better understand their places in the synapsid family tree. My goal is to build on the work previous paleontologists did, but also to answer new questions and gain new insights into synapsid evolution and the origins of the distinctive features that characterize mammals today.

What’s the most interesting part of your job?

Being able to do research and indulge my natural curiosity about paleontology is a real privilege. It’s a dream job; I’ve wanted to be a paleontologist for as long as I can remember. It’s also pretty mind-blowing to excavate a fossil and realize that you’re the first living thing to see that animal in over 250 million years.

What do you want to share with people on Ask A Curator Day?

Everyone uses the scientific method in day-to-day life, whether or not you realize it! When confronted with a question or problem, you make observations, collect available information, and perform tests to see what works. The underlying object is the same as in scientific research.  Scientists are constantly working to understand the natural world around us, and we do so by asking questions and trying to find ways to answer those questions.

The Field is a place to exercise your natural curiosity by visiting the DNA Discovery Center, doing community science, volunteering, and starting to look at the world in a different way.

Learn more about Ken’s work in the three-part series “Harvard Adventures” on The Brain Scoop.

Ken Angielczyk
MacArthur Curator of Paleomammalogy and Section Head

I am a paleobiologist interested in three main topics: 1) understanding the broad implications of the paleobiology and paleoecology of extinct terrestrial vertebrates, particularly in relation to large scale problems such as the evolution of herbivory and the nature of the end-Permian mass extinction; 2) using quantitative methods to document and interpret morphological evolution in fossil and extant vertebrates; and 3) tropic network-based approaches to paleoecology. To address these problems, I integrate data from a variety of biological and geological disciplines including biostratigraphy, anatomy, phylogenetic systematics and comparative methods, functional morphology, geometric morphometrics, and paleoecology.

A list of my publications can be found here.

More information on some of my research projects and other topics can be found on the fossil non-mammalian synapsid page.

Most of my research in vertebrate paleobiology focuses on anomodont therapsids, an extinct clade of non-mammalian synapsids ("mammal-like reptiles") that was one of the most diverse and successful groups of Permian and Triassic herbivores. Much of my dissertation research concentrated on reconstructing a detailed morphology-based phylogeny for Permian members of the clade, as well as using this as a framework for studying anomodont biogeography, the evolution of the group's distinctive feeding system, and anomodont-based biostratigraphic schemes. My more recent research on the group includes: species-level taxonomy of taxa such as Dicynodon, Dicynodontoides, Diictodon, Oudenodon, and Tropidostoma; development of a higher-level taxonomy for anomodonts; testing whether anomodonts show morphological changes consistent with the hypothesis that end-Permian terrestrial vertebrate extinctions were caused by a rapid decline in atmospheric oxygen levels; descriptions of new or poorly-known anomodonts from Antarctica, Tanzania, and South Africa; and examination of the implications of high growth rates in anomodonts. Fieldwork is an important part of my paleontological research, and recent field areas include the Parnaíba Basin of Brazil, the Karoo Basin of South Africa, the Ruhuhu Basin of Tanzania, and the Luangwa Basin of Zambia. My collaborators and I have made important discoveries in the course of these field projects, including the first remains of dinocephalian synapsids from Tanzania and a dinosaur relative that implies that the two main lineages of archosaurs (one including crocodiles and their relatives and the other including birds and dinosaurs) were diversifying in the early Middle Triassic, only a few million years after the end-Permian extinction. Finally, the experience I have gained while studying Permian and Triassic terrestrial vertebrates forms the foundation for work I am now involved in using models of food webs to investigate how different kinds of biotic and abiotic perturbations could have caused extinctions in ancient communities.

Geometric morphometrics is the basis of most of my quantitative research on evolutionary morphology, and I have been using this technique to address several biological and paleontological questions. For example, I conducted a simulation-based study of how tectonic deformation influences our ability to extract biologically-relevant shape information from fossil specimens, and the effectiveness of different retrodeformation techniques. I also used the method to address taxonomic questions in biostratigraphically-important anomodont taxa, and I served as a co-advisor for a Ph.D. student at the University of Bristol who used geometric morphometrics and finite element analysis to examine the functional significance of skull shape variation in fossil and extant crocodiles. Focusing on more biological questions, I am currently working on a large geometric morphometric study of plastron shape in extant emydine turtles. To date, I have compiled a data set of over 1600 specimens belonging to nine species, and I am using these data to address causes of variation at both the intra- and interspecific level. Some of the main goals of the work are to examine whether plastron morphology reflects a phylogeographic signal identified using molecular data in Emys marmorata, whether the "miniaturized" turtles Glyptemys muhlenbergiiand Clemmys guttata have ontogenies that differ from those of their larger relatives, and how habitat preference, phylogeny, and shell kinesis affect shell morphology.

A collaborative project that began during my time as a postdoctoral researcher at the California Academy of Sciences involves using using models of trophic networks to examine how disturbances can spread through communities and cause extinctions. Our model is based on ecological principles, and some of the main data that we are using are a series of Permian and Triassic communities from the Karoo Basin of South Africa. Our research has already shown that the latest Permian Karoo community was susceptible to collapse brought on by primary producer disruption, and that the earliest Triassic Karoo community was very unstable. Presently we are investigating the mechanics that underlie this instability, and we're planning to investigate how the perturbation resistance of communities as changed over time. We've also experimented with ways to use the model to estimate the magnitude and type of disruptions needed to cause observed extinction levels during the end-Permian extinction event in the Karoo. Then there's the research project I've been working on almost my whole life.

Morphology and the stratigraphic occurrences of fossil organisms provide distinct, but complementary information about evolutionary history. Therefore, it is important to consider both sources of information when reconstructing the phylogenetic relationships of organisms with a fossil record, and I am interested how these data sources can be used together in this process. In my empirical work on anomodont phylogeny, I have consistently examined the fit of my morphology-based phylogenetic hypotheses to the fossil record because simulation studies suggest that phylogenies which fit the record well are more likely to be correct. More theoretically, I developed a character-based approach to measuring the fit of phylogenies to the fossil record. I also have shown that measurements of the fit of phylogenetic hypotheses to the fossil record can provide insight into when the direct inclusion of stratigraphic data in the tree reconstruction process results in more accurate hypotheses. Most recently, I co-advised two masters students at the University of Bristol who are examined how our ability to accurately reconstruct a clade's phylogeny changes over the course of the clade's history.