EARLY MAMMALIAN MASTICATION AND CORTICAL EVOLUTION
What it is
Early mammalian and pre-mammalian fossils display a number of novel morphologies. This includes complex tooth occlusion, a single set of replacement teeth, an ossified secondary palate, and an expanding cortex. These characters suggest a more complex mastication (chewing) behavior in these Triassic animals that may have allowed for more efficient breakdown of food. Thus, more calories could support an expanding brain.
Why it matters
Modern opossums are often used as a proxy for early mammals, as they are morphologically similar to their Triassic counterparts. For my PhD I am comparing opossum mastication with a highly derived animal, the rhesus macaque, as well as a lizard for an outgroup comparison. I am using neurological, morphological, and behavioral mastication data to compare these three taxa.
A separate study will focus specifically on innervation of the ligaments that connect teeth to the skull and mandible.
What it is
Early mammalian and pre-mammalian fossils display a number of novel morphologies. This includes complex tooth occlusion, a single set of replacement teeth, an ossified secondary palate, and an expanding cortex. These characters suggest a more complex mastication (chewing) behavior in these Triassic animals that may have allowed for more efficient breakdown of food. Thus, more calories could support an expanding brain.
Why it matters
Modern opossums are often used as a proxy for early mammals, as they are morphologically similar to their Triassic counterparts. For my PhD I am comparing opossum mastication with a highly derived animal, the rhesus macaque, as well as a lizard for an outgroup comparison. I am using neurological, morphological, and behavioral mastication data to compare these three taxa.
A separate study will focus specifically on innervation of the ligaments that connect teeth to the skull and mandible.
AUSTRALIAN AGAMID SKULL ONTOGENY AND MORPHOLOGY
What it is
Lizards are notoriously hard to identify in the fossil record. Now take five modern Agamid "dragons", all closely related (i.e. different species of the same family), and deflesh them. What do you have? That's what I am going to find out! I am currently studying an entire series of agamids, all in different stages of life.
Why it matters
We know comparatively little about the life-histories of these lizards, how they grow and develop, and if they all look "the same" inside the skull or completely different! Agamids are a great study system for phenotypic plasticity and selection pressure.
What it is
Lizards are notoriously hard to identify in the fossil record. Now take five modern Agamid "dragons", all closely related (i.e. different species of the same family), and deflesh them. What do you have? That's what I am going to find out! I am currently studying an entire series of agamids, all in different stages of life.
Why it matters
We know comparatively little about the life-histories of these lizards, how they grow and develop, and if they all look "the same" inside the skull or completely different! Agamids are a great study system for phenotypic plasticity and selection pressure.
OSTEOPATHOLOGY IN RHINOCEROTIDAE FROM 50 MYA TO THE PRESENT
What It Is
An osteopathology is the result of a trauma or a disease that happens to a bone. This could be anything from a break in the bone to infectious cysting. I am looking at a number of pathologies in the North American rhino lineage (about 50 to about five million years ago or so). Rhinos also increase in size from about the size of a large dog to a multi-ton animal over this same time span and I want to know how this exponential increase in mass affects osteopathological expression (such as arthritis).
Why it Matters
There have been very few projects that attempt to look at pathology in non-human animals on the population-level, and even fewer that consider the fossil record. Do these pathologies become so severe as to be an evolutionary constraint or is pathology independent of phylogeny? And what does this imply for the future of wild and captive animals?
Check out this article in The Economist about this project!
What It Is
An osteopathology is the result of a trauma or a disease that happens to a bone. This could be anything from a break in the bone to infectious cysting. I am looking at a number of pathologies in the North American rhino lineage (about 50 to about five million years ago or so). Rhinos also increase in size from about the size of a large dog to a multi-ton animal over this same time span and I want to know how this exponential increase in mass affects osteopathological expression (such as arthritis).
Why it Matters
There have been very few projects that attempt to look at pathology in non-human animals on the population-level, and even fewer that consider the fossil record. Do these pathologies become so severe as to be an evolutionary constraint or is pathology independent of phylogeny? And what does this imply for the future of wild and captive animals?
Check out this article in The Economist about this project!
FLUVIAL TAPHONOMIC BIAS
What it is
Taphonomy is what happens to a bone between death and final burial. This could be dispersal of bones by a predator, decomposition, or even the weather. Physical scattering processes, like dispersal through a steam or river, can be systematic, and thus measurable. We measured the greatest length, width, and height of over 5,000 fossils that were deposited in three ancient streambeds from Oregon to see if we could mathematically eliminate the systematic sorting effect of the stream (i.e. bias).
Why it matters
In order to understand ancient ecosystems, we first have to have an accurate count of the flora and fauna. Working backwards like this isn't as simple as directly comparing to modern ecosystems, because we don't know if the balances were the same back then (and they probable were not). We are much more likely to glimpse the future of climate change if we first understand the past.
What it is
Taphonomy is what happens to a bone between death and final burial. This could be dispersal of bones by a predator, decomposition, or even the weather. Physical scattering processes, like dispersal through a steam or river, can be systematic, and thus measurable. We measured the greatest length, width, and height of over 5,000 fossils that were deposited in three ancient streambeds from Oregon to see if we could mathematically eliminate the systematic sorting effect of the stream (i.e. bias).
Why it matters
In order to understand ancient ecosystems, we first have to have an accurate count of the flora and fauna. Working backwards like this isn't as simple as directly comparing to modern ecosystems, because we don't know if the balances were the same back then (and they probable were not). We are much more likely to glimpse the future of climate change if we first understand the past.
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