Saturday, February 15, 2014

Paleo parturition

Study the fossil above for a moment to make sense of it. The complete animal on the lower right is an embryonic 248-million-year-old ichthyosaur. But you will notice a vertebral column above it and a pelvis to the left, which indicates that it is emerging from the mother's womb (SEE COLOR-CODED DIAGRAM HERE). The find came out of recent excavations in south Majiashan, Anhui, China, led by paleontologist Guan-bao Chen of Anhui Geological Museum. The dig yielded more than 80 skeletons of the lizard-like Chaohusaurus, the oldest of Mesozoic marine reptiles but, at 6' (1.8 m) in length, one of the smallest ichthyosaurs. This particular specimen is even more momentous than mites procreating when they were covered by sap 40 million years ago or turtles caught in the act when they were overcome by volcanic gases 47 million years ago. Lead author of the newly published paper in the journal PLoS ONE Ryosuke Motani from the University of California, Davis, explains, The study reports the oldest vertebrate fossil to capture the ‘moment’ of live-birth, with a baby emerging from the pelvis of its mother. The 248-million-year old fossil of an ichthyosaur suggests that live-bearing evolved on land and not in the sea.”

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