Proneotherium

Proneotherium Temporal range: Early Miocene, 20.43–15.97 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓

Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Clade:	Pinnipedia
Family:	Odobenidae
Genus:	†Proneotherium Kohno et al., 1995
Species:	†P. repenningi
Binomial name
†Proneotherium repenningi Kohno et al., 1995

Proneotherium is an extinct genus of pinniped that lived approximately 20.43 to 15.97 mya^[1] during the Early Miocene in what is now Oregon, U.S. It belonged to the family Odobenidae, the only extant species of which is the walrus.

Discovery

Four specimens of Proneotherium were discovered in the Astoria Formation of Lincoln County, Oregon, U.S. These specimens included cranial and postcranial remains and are all believed to be adult male animals.^[2]

Description

Proneotherium was more similar in appearance to modern fur seals and sea lions than walruses. They lacked the long tusks of walruses, and were more slender and smaller than their modern relatives.

Autapomorphies of Proneotherium fossils include a continuous, horizontal crest connecting the mastoid and paroccipital processes of the skull. The teeth are also less secodont in function and appearance than more basal species.^[2] This likely represents the slow shift from a piscivorous diet to the mollusk-based diet of modern walruses. The hindlimbs of Proneotherium also show the beginnings of evolutionary shifts from a terrestrial lifestyle to a more aquatic one.^[2]

Taxonomy

Proneotherium represents some of the most basal members of Odobenidae. The sister group is the closely related Prototaria.

References

^ "†Proneotherium Kohno et al. 1995 (walrus)". Fossilworks. Retrieved 17 December 2021.
^ ^a ^b ^c Deméré, T.A.; Berta, A. (1 July 2001). "A reevaluation of Proneotherium repenningi from the Miocene Astoria Formation of Oregon and its position as a basal odobenid (Pinnipedia: Mammalia)" (PDF). Journal of Vertebrate Paleontology. 21 (2): 279–310. doi:10.1671/0272-4634(2001)021[0279:AROPRF]2.0.CO;2 – via BioOne Complete.

Genera of pinnipeds and their stem-allies

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Infraorder: Arctoidea

Pan-Pinnipedia

†Amphicynodontidae	Allocyon Amphicticeps Amphicynodon Drassonax Kolponomos Pachycynodon Parictis Wangictis
†Semantoridae	Necromites Potamotherium Puijila Semantor

Pinnipedimorpha

†Enaliarctos

Pinnipediformes

†Pacificotaria
†Pinnarctidion
†Pteronarctos

Pinnipedia

Phocidae

†Devinophoca

Monachinae

†Magnotherium
Monachini	†Afrophoca †Auroraphoca †Messiphoca Monachus Neomonachus †Eomonachus †Noriphoca †Palmidophoca †Pliophoca †Pontophoca †Pristiphoca †Terranectes
Miroungini	†Callophoca Mirounga
Lobodontini	†Acrophoca †Australophoca †Hadrokirus †Homiphoca Hydrurga Leptonychotes Lobodon Ommatophoca †Piscophoca †Properiptychus †Virginiaphoca

Phocinae

†Cryptophoca †Frisiphoca †Kawas †Leptophoca †Monachopsis †Monotherium †Phocanella †Prophoca †Sarmatonectes
Erignathini	Erignathus †Platyphoca
Cystophorini	Cystophora †Miophoca †Pachyphoca
Phocini	†Batavipusa †Gryphoca Halichoerus Histriophoca †Nanophoca Pagophilus Phoca †Planopusa †Praepusa Pusa

Otarioidea	see below↓

Otarioidea

†Desmatophocidae

Allodesmus
Atopotarus
Desmatophoca
Eodesmus

Odobenidae

†Archaeodobenus
†Imagotaria
†Kamtschatarctos
†Nanodobenus
†Neotherium
†Osodobenus
†Pelagiarctos
†Pontolis
†Proneotherium
†Prototaria
†Pseudotaria
†Titanotaria

Neodobenia

†Dusignathinae	Dusignathus Gomphotaria
Odobeninae	†Aivukus Odobenus †Ontocetus †Pliopedia †Protodobenus †Valenictus

Panotariidae

†Eotaria

Otariidae

Callorhinae

Callorhinus
†Pithanotaria

Otariinae

†Thalassoleon
Zalophini	Eumetopias †Oriensarctos †Proterozetes Zalophus
Otariini	Arctocephalus Arctophoca †Hydrarctos Neophoca Otaria Phocarctos

Lists
List of pinnipeds List of fossil pinnipedimorphs

This page was last edited on 2 January 2024, at 09:31

From Wikipedia, the free encyclopedia

Discovery

Description

Taxonomy

References