アメリカ自然史博物館のインスタグラム(amnh) - 10月15日 02時23分

#NationalFossilDay Puzzle 4/6: The main power source in a mammal skull for generating forceful bites is the jaw-closing muscles located on top of the head and around the cheeks. In predators, the muscle group on top of the head, the temporalis muscles, is relatively large both in area coverage and in volume. By comparison, herbivorous mammals tend to have strong cheek muscles. This fossil mammal had a huge bony crest on top of its head, where strong temporalis muscles attached. By comparison, the zygomatic arches below and behind the orbit (see photo #2), where cheeks muscles attach, are slender given the size of the skull. Have you guessed which fossil mammal this is yet?

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