EEB386H1 Lecture Notes - Lecture 2: Archaeopteryx, Endocast, American Museum Of Natural History
20 Jul 2014
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Lecture 2: origins and evolution of birds. The thermopolis specimen (in wyoming), shows 3 forelimb digits clearly, but metacarpals are unfused. The archaeopteryx retained reptilian features (teeth, long tail, and semilunate carpal at the hand) Fluorescence x- ray analysis revealed there is actual feather remnants in there and not just impressions. Can also see that the teeth has waste on them not like close relatives (dinosaurs), more like crocodiles. In the synchroton x- ray fluorescence, we see the teeth, hand with claws, diffused clavicles: picks up different elements (ex. Phosphorus: there are phosphorus in bones, chemical composition, see packages of melanin in feathers. If you put feathers on the compsognathus longipes, it will be archaeopteryx. Cladistics: groupings (clades) based on shared derived features. Kinetic skull, raptorial claw, bipedality) theropods had a furcula, as does archaeopteryx and birds. Heilmann argues that any similarities between dinosaurian reptiles and birds was due to convergence and not descent unrelated.
