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Published: July 24, 2012

Brazil 2012 Fieldwork Diary Entry 12: Cachaça on the Rocks

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

We traveled back to Teresina from Nova Iorque today. A little more than halfway between the two cities is the town of Amarante, and just outside of Amarante are some rock exposures we visited last year. The exposures are supposed to contain the contact between the Pedra de Fogo Formation and the older Piauí Formation that underlies it. The Piauí Formation is thought to have formed in a marine environment, and the contact between the formations is not well exposed near Nova Iorque, so we thought this would be a good place for Roger to see it and fill in his knowledge about the oldest rocks of the Pedra De Fogo Formation. The exposure of interest is located close to the road to Teresina, but somewhat below it, so we had to climb down and then work our way back up the exposure, studying the rocks as we went.

A 50 litre can of cachaça at the distillery we visited. Photo by Ken Angielczyk.

I almost feel guilty about the pun in the title of this entry, but it does capture two of the important things we did today. Since it's a science blog, I'll start with the science side of things.

We traveled back to Teresina from Nova Iorque today. A little more than halfway between the two cities is the town of Amarante, and just outside of Amarante are some rock exposures we visited last year. The exposures are supposed to contain the contact between the Pedra de Fogo Formation and the older Piauí Formation that underlies it. The Piauí Formation is thought to have formed in a marine environment, and the contact between the formations is not well exposed near Nova Iorque, so we thought this would be a good place for Roger to see it and fill in his knowledge about the oldest rocks of the Pedra De Fogo Formation. The exposure of interest is located close to the road to Teresina, but somewhat below it, so we had to climb down and then work our way back up the exposure, studying the rocks as we went.

Hiking down to the Piauí Formation near Amarante. Photo by Ken Angielczyk.

The surprising thing is that the rocks did not seem to have a strong marine character to them. Instead, the appeared rather similar to rocks we were seeing in the Pedra de Fogo Formation. For example, some of the features of the bedding (or layering of the rocks) and the presence of small, round grains called ooids are consistent with the rocks having been formed in a shallow lake or near the edge of a seaway. There were also somewhat more terrestrial rocks present, including ones with mineral crusts called rhizocretions that form around plant roots in certain soil types. At the top of the hill, near the level of the road, are rocks that represent sand dunes similar to the ones we saw near the top of the Pedra de Fogo Formation near Pastos Bons, even though these are supposed to be near the bottom of the formation in the area near Amarante. Different interpretations of these observations are possible. One is that the rocks are mapped incorrectly in this area. In other words, previous geologists might have mistakenly assigned rocks belonging to the Pedra de Fogo Formation to the Piauí Formation. Alternatively, if at least some of the rocks belonging to the Piauí Formation represent sand dunes and shallow water environments located in their vicinity, this could mean the this general style of environment persisted in the Parnaíba Basin for some time. Indeed, even the Motuca Formation, which overlies the Pedra de Fogo, seems to have been largely formed by sand dunes. In that case, the Pedra de Fogo Formation would capture a snapshot of the animals and plants living in these environments. At the moment, I think I support this interpretation, given that the Parnaíba Basin was located near central Pangaea at the time, and desert environments are expected to have been present in the subtropical portions of such a large continental landmass. The Pedra de Fogo Formation might include more fossils than the Piauí or Motuca formations because it happened to be deposited at a time when conditions were slightly wetter or sea level was a bit higher resulting in the assemblage of animals dominated by fish and amphibians.

Besides the outcrops of the Piauí Formation, another thing that is conveniently located close to Amarante is the distillery for Cachaça Lira. Cachaça is a spirit distilled from fermented sugarcane juice that is very popular in Brazil. It's sometimes compared to rum, but differs from the latter in that fresh sugarcane juice is fermented to make cachaça, whereas molasses is usually the starting point for rum. The Cachaça Lira distillery is still run by descendants of the man who started it in the late 1880's, and is extremely picturesque. The family is very welcoming, and it's a wonderful place to stop on a hot afternoon to chat, eat fresh carambola (star fruit) from the tree in the garden, and have a sip of cachaça.

Where the magic happens: the Cachaça Lira distillery. Photo by Ken Angielczyk.

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.

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