Last Non-Mammal Mammaliaforms

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By Michael Alan Prestwood

Sat 23 May 2026

Published 4 months ago.

Updated 4 months ago.

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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Michael Alan Prestwood
Author & Natural Philosopher

Prestwood writes on science-first philosophy, with particular attention to the convergence of disciplines. Drawing on his TST Framework, his work emphasizes rational inquiry grounded in empirical observation while engaging questions at the edges of established knowledge. With TouchstoneTruth positioned as a living touchstone, this work aims to contribute reliable, evolving analysis in an emerging AI era where the credibility of information is increasingly contested.