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News Release 18-080
What makes a mammal a mammal? Our spine, say scientists
Study of fossil bones leads to new conclusions about spine's importance
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Reconstruction of Edaphosaurus, a primitive mammal ancestor; its long spines form a sail on its back.
Credit: Harvard University Museum of Comparative Zoology
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Phylogenetic tree showing mammal backbone evolution: Edaphosaurus, Thrinaxodon, today's mouse.
Credit: Harvard University Museum of Comparative Zoology
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Edaphosaurus fossils came from late Carboniferous to early Permian times, 300-280 million years ago.
Credit: Harvard University Museum of Comparative Zoology
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Reconstruction of Thrinaxodon; fossil bones came from the Early Triassic, 251-241 million years ago.
Credit: April Neander
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A modern-day opossum shows the addition of a fifth region in the backbone, the lumbar region.
Credit: Harvard University Museum of Comparative Zoology
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A fossil specimen of Thrinaxodon, on display in the Harvard Museum of Natural History.
Credit: Harvard University Museum of Comparative Zoology
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