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Morganucodon (Wikimedia Commons)


Morganucodon (Greek for "Glamorgan tooth"); pronounced MORE-gan-oo-CODE-on


Woodlands of Europe, Asia and North America

Historical Period:

Late Triassic (215 million years ago)

Size and Weight:

About four inches long and one ounce



Distinguishing Characteristics:

Small size; reptilian jaw


About Morganucodon:

The geological record is littered with transitional forms between the therapsids ("mammal-like reptiles") and early mammals of the late Triassic period, and Morganucodon is among the most common. The remains of this shrew-like creature have been found across the northern hemisphere, and convey the image of a small, skittish critter with an odd mix of mammalian (hair and teeth) and reptilian (lower jaw) characteristics. (By the way, the name Morganucodon is often translated as "Morgan's tooth," but this prehistoric mammal is really named after Glamorgan, the part of Wales where its remains were first discovered.)

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