Archive for April, 2011

Alligators are everywhere. They’re team mascots, Transformer toys, actors in Lubriderm commercials (and CSI: Miami), unwanted golfing partners, and even expensive cowboy boots. What might be a surprise is that they’re also “model animals” for scientists, meaning that there are dozens, if not hundreds, of published technical articles on all things gatorly. They’re also commonly used in K-12 and undergraduate classrooms. WitmerLab has been working on American alligators for years, because crocodilians are one of just two living groups (birds are the other) of that great tribe known as archosaurs that includes dinosaurs and pterosaurs. Now, we’re joining with Casey Holliday’s lab at the University of Missouri to present the 3D Alligator, two parallel, complementary, and growing websites that present alligator anatomy in all its 3D digital glory. In both cases, we’re starting with the skull, although we include a few soft-tissue systems that are active areas of research for us (brain, inner ear, sinuses, etc.). Casey’s team presents an adult skull, and we present a wee gatorling, a “day-0” hatchling that was stillborn on its birthday. Sad perhaps, but this little guy is now immortal, because we’re releasing him to the tubes of the interwebz. We also present some of our 3D alligator work on an adult done “way back” in 2008. Check out the WitmerLab 3D Alligator site and the Holliday Lab 3D Alligator site. (more…)

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Evolution in birds of the olfactory bulb, the part of the brain where smell information is processed, passing from a dinosaur (Bambiraptor) through early birds (Lithornis, Presbyornis) to a modern-day bird (pigeon).

Birds have a lousy sense of smell, right? That common perception may apply to some modern-day birds, but that wasn’t always the case. Early birds, frankly, smelled like dinosaurs, meaning that they inherited a pretty respectable sense of smell from their dinosaurian kin. The typical scenario had been that as birds evolved flight, the senses of vision and balance increased and the olfactory sense diminished. Darla Zelenitsky (University of Calgary) and François Therrien (Royal Tyrrell Museum) invited Ryan Ridgely and me to join forces in testing this scenario by studying the evolution of the olfactory bulb, the part of the brain receiving information on odors, across the transition from small theropod dinosaurs to birds. As our new article in Proceedings of the Royal Society B reveals, birds started out with a full sensory toolkit, including a pretty capable sniffer. And we also learned a thing or two about non-avian theropods along the way.

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