''Allodesmus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant taxon, extant families Odobenidae (whose onl ...

from the middle to late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

that belongs to the

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

pinniped

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Desmatophocidae Desmatophocidae is an extinct family of pinnipeds closely related to either the eared seals and walruses or to the earless seals. These animals were the first group of large-bodied pinnipeds to evolve, first appearing in the Early Miocene, with n ...

Description and biology

''Allodesmus'' measured about long and weighed . ''Allodesmus'' had the specific anatomical features found in modern polygynous pinnipeds:

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, strong canines for fights between bulls and teeth with well-defined growth zones, a result from periodic fasting (in order to defend their

harem A harem is a domestic space that is reserved for the women of the house in a Muslim family. A harem may house a man's wife or wives, their pre-pubescent male children, unmarried daughters, female domestic Domestic worker, servants, and other un ...

, males would not take to the sea to feed during the breeding season).

Taxonomy

''Allodesmus sinanoensis'' and ''A. packardi'' were previously assigned separate genera, ''Megagomphos'' and ''Brachyallodesmus'', respectively, but many authors questioned this generic distinction, and the cladistic analysis by Boessenecker and Churchill (2018) found no support for this generic scheme. ''

Atopotarus ''Atopotarus'' is an extinct genus of pinniped from the middle Miocene of Los Angeles County, California. It is a monotypic genus, with the only known species being ''Atopotarus courseni'', or commonly referred to as 'Coursen's Strange Seal;' the ...

'', referred to ''Allodesmus'' by some authors (e.g. Mitchell 1966), is distinct from ''Allodesmus'' by the absence of a prenarial shelf and M2, double-rooted cheek teeth, a small, triangular postorbital process, and a mastoid process projecting ventral to the postglenoid process.Robert W. Boessenecker; Morgan Churchill (2018). "The last of the desmatophocid seals: a new species of Allodesmus from the upper Miocene of Washington, USA, and a revision of the taxonomy of Desmatophocidae". Zoological Journal of the Linnean Society. Online edition. doi:10.1093/zoolinnean/zlx098.

References

* Encyclopedia of Marine Mammals, ed. William F. Perrin,

Bernd Würsig Bernd Gerhard Würsig (born 9 November 1948 in Barsinghausen, Germany)"Bernd Gerhard Würsig". Marqui's Who's Who in the World. 2012. 29th Edition. is an educator and researcher who works mainly on aspects of behavior and behavioral ecology of w ...

, J.G.M. Thewissen

External links

Miocene pinnipeds Fossils of Japan Fossils of the United States Fossil taxa described in 1922 Miocene California Prehistoric carnivoran genera {{paleo-carnivora-stub