Published: July 22, 2012

Brazil 2012 Fieldwork Diary Entry 7: Nova Iorque, Nova Iorque

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

One of the ironies of writing this blog for the New York Times is that we're staying in a town called Nova Iorque, which is Portuguese for New York. It's a quaint little town located on the edge of a lake called Boa Esperança (Good Hope) that was made by damming the Parnaíba River in 1969. Indeed, the original location of the town is now underwater in the lake. It's a very convenient place to stay because it is just a few kilometers from the outcrops we're working on at the moment, and there are a couple of little restaurants near the lake that make excellent food using local fish.

The town logo of Nova Iorque. Photo by Ken Angielczyk.

One of the ironies of writing this blog for the New York Times is that we're staying in a town called Nova Iorque, which is Portuguese for New York. It's a quaint little town located on the edge of a lake called Boa Esperança (Good Hope) that was made by damming the Parnaíba River in 1969. Indeed, the original location of the town is now underwater in the lake. It's a very convenient place to stay because it is just a few kilometers from the outcrops we're working on at the moment, and there are a couple of little restaurants near the lake that make excellent food using local fish.  According to Juan, the original (and now underwater) town of Nova Iorque was a port on the Parnaíba River that was used for shipping palm oil made from a variety of coconut that grows in the area. The engineer who designed the port was from New York, hence the name of the town.

Top: The church in the town square in Nova Iorque. Photo by Ken Angielczyk. Bottom: The guest of honor at dinner: a type of catfish called a surubim. This specimen is only a medium-sized individual. The woman holding it turned it into a delicious meal of fried and stewed fish. Photo by Roger Smith.

We're doing our fieldwork at the end of the rainy season in this area. There are advantages and disadvantages to this. The main advantages are that it is a bit cooler at this time of year than during the dry season, and the rain sometimes makes fossils easier to see in the outcrops because it cleans them off. The disadvantage is that when it rains, it really rains. We had a huge thunderstorm last night, which wasn't too much of a problem except for a few leaks in the roof of our house. However, we also got caught in a heavy downpour while we were out in the field this morning, and we ended up totally soaked. In fact, I'm currently writing this post around lunch time because we are back at the houses trying to dry off our clothes and gear.

Crossing the Pedra de Fogo River during a heavy rainfall. On April 14 we studied rocks in the dry river bed just a few hundred meters from here; what a difference some rain makes. In the bottom right is a camera mounted to the hood of our truck that Jeff is using to get footage of our travels. Photo by Ken Angielczyk.

The houses that we're staying in are located just on the shore of the lake. They're nothing fancy, but they provide a nice view of the lake while we eat breakfast, as well as very nice sunsets on the days we get back before dark. Staying in houses while doing fieldwork is a bit of a luxury (particularly since we can shower every day after work!), but there aren't many good areas to camp that are closer to the outcrops.

Sunset over Boa Esperança. Photo by Ken Angielczyk.

Tomorrow our plan is to try to find a couple of localities where previous researchers collected fossils. These collections were made in the days before GPS, so they used local landmarks in the scientific papers describing the specimens to indicate where they were from (e.g., 5 kilometers from town, 300 meters east of the road). Using our GPS receivers and the satellite photos available on Google Earth, we can get a good general idea of where these places are, but it can be frustratingly difficult to be sure whether we're really in the right place. We also have some old photos sent to us by one of the scientists set us, but they include features that can be used to differentiate one outcrop from another. Nevertheless, they found some of the few terrestrial vertebrate fossils known from the Pedra de Fogo Formation at the localities, so it's important for us to try to return to them to see whether 40+ years of erosion has exposed any new material.


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.