Imagotaria

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Imagotaria
Temporal range: Late Miocene
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Clade: Pinnipedia
Family: Odobenidae
Genus: †Imagotaria
Species:
†I. downsi
Binomial name
†Imagotaria downsi
Mitchell, 1968

Imagotaria is an

Fossils of Imagotaria are known from the early late Miocene of California
(c. 10-12 million years ago).

Description

The 1.8 metres (6 ft) long

tusks, but instead bore enlarged canines (with respect to other pinnipeds).[1]

Imagotaria is an example of a primitive walrus that does not grossly appear similar to a modern walrus. However, the walrus family (the

Dusignathinae), and walruses with upper tusks like the extant walrus (subfamily Odobeninae, tribe Odobenini). It is possible to classify these pinnipeds as walruses because they share many other skull
features (besides tusks) as well as many skeletal features, all of which indicate common ancestry.

Palaeobiology

The

sea otters
do. Instead, they hold a clam in their lips, and the vaulted palate allows them to use their tongue as a powerful piston to suck the soft parts right out of the clam shell. The shell is then dropped to the seafloor, never entering the oral cavity.

Additionally, fossils of Imagotaria (and the earlier Neotherium, c. 15 million years ago) demonstrate that early walruses had, by the middle and late Miocene, already developed extreme sexual dimorphism (males and females having different body sizes). It is unclear whether extreme sexual dimorphism is ancestral to all pinnipeds, or if it has been independently acquired in multiple pinniped lineages.

References

  1. ISBN 1-84028-152-9
    .
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