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updated 06 March 2008
Research
Although most of my research centers around vertebrate paleobiology, answering such questions can often be done only by using modern animals as models. Therefore, current, future, and previous research focuses on functional morphology of living vertebrates. Data from these projects may then used to interpret the biology of extinct groups.
Evolution of Endothermy
By combining empirical studies of modern animals with close scrutiny of fossils, we have been able to elucidate the morphology of the nasal passage as well as lung structure of theropod dinosaurs, which resulted in a virtual paradigm shift in the interpretation of dinosaur metabolic physiology. Briefly, endotherms (e.g., birds and mammals) have structures within their nasal passages (respiratory turbinates) that act as intermittent countercurrent heat and water exchangers. These enable them to have increased ventilatory rates associated with high resting O2 consumption. Conversely, ectotherms lack respiratory turbinates, have relatively low lung ventilation and O2 consumption rates. As a result, they have relatively narrow nasal passages (see right).
I continue to investigate the fossil record of mammals, birds, dinosaurs, and their relatives for testable evidence of respiratory and metabolic status.
I am also currently working on several projects with modern animals that are related to these questions.
Origin
of Feathers
Over the last few years the origin of feathers has become a relatively controversial topic among paleontologists. As part of my dissertation research I was fortunate enough to have the opportunity to study Longisquama insignis (left), an animal that likely possessed the earliest known feathers (and pre-dates the earliest birds by about 75 million years).
I am currently working on an SEM analysis of the fibrous structures associated with the integument (skin) of "feathered" dinosaurs from Northeastern China to understand how these may fit into the evolutionary picture.Student Research
Students interested in working with me may be interested in almost any aspect of vertebrate biology and not only paleobiology.