Multituberculate fossils have been found mainly in the Northern
hemishpere, although a few isolated teeth have been found in Argentina,
Morocco and Madagascar.
The oldest multituberculates are known from isolated teeth dating back
to the Middle Jurassic, around 165 million years ago (Butler and
Of the Jurassic and Cretaceous forms, only teeth, upper and lower jaws,
and fragments of skull material are known. All of these
multituberculates belong to the Plagiaulacida
suborder, which includes
the ancestors of the late Cretaceous and early Tertiary Cimolodonta.
The early Cretaceous forms begin to show the modifications in teeth
structure which are characteristic of their descendants, for example
the third row of cusps on the upper molars.
The best record of Cretaceous multituberculates comes from late
Cretaceous deposits in Mongolia; hundreds of skulls, often associated
to skeletons, have been found in the Gobi Desert. The North American
Late Cretaceous multituberculate forms are less complete. The European
record for this time consists of a skull and isolated teeth.
Fossils of North American and Chinese Tertiary multituberculates are
much more complete; many of the skulls are intact and the skeletons are
preserved. In Europe, only isolated teeth are known. The
multituberculates went extinct in the mid-Tertiary, possibly
outcompeted by rodents.
The lower jaw of a Sinobaatar
(Plagiaulacid line) has been found preserved in the abdomen of a
feathered dinosaur, Sinosauropteryx,
which shows that these small mammals were eaten by larger carnivores
(Hurum et al.,
Multituberculate hair was found in the fossilised faeces of other
Although no exceptionally preserved soft tissues have been found, much
can be deduced from the bones. The brain has been visualised by
X-ray/CT scanning of complete skulls, and muscles and blood vessels
have been reconstructed from the clues they have left on the bones,
like ridges for muscle attachment.
and Anatomy |
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Author: Aude Caromel
Last updated: 20/11/06
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produced by students
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