Last Non-Mammal Mammaliaforms
~66 Million years ago (tentative placeholder date)
The Avashishta bacharamensis is dated to about 72 to 66 million years ago. It is known from a single tooth from Late Cretaceous India, Avashishta may represent a late-surviving haramiyidan, a non-mammalian mammaliaform near the mammal line. Its classification is debated, so this is best marked as a tentative “possible last known” entry.
For sure, non-mammal mammaliaforms lived to about 150 million years ago. For example, the Late Jurassic docodont mammaliaform from Portugal. It had many mammal-like traits, including complex teeth and mammaliaform-style tooth replacement, but belonged to a side branch outside the living mammal line.
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Not every mammaliaform became a mammal; some were late-surviving side branches near the mammal line.
Subject: Mammal Evolution.
Evolution rarely moves in a straight line. The last non-mammal mammaliaforms remind us that nature explores many paths at once. Some branches become the future. Others fade away after millions of successful years. The story of mammals is not a ladder upward, but a tangled forest of near-successes, side paths, and survivors.
What group includes both surviving crown mammals and their extinct mammal cousins?.
Answer. Mammaliaforms or stem mammaliaforms..
was first published on TST 4 months ago.
