Pontolis

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Pontolis
Temporal range: Miocene-Pliocene
Pontolis barroni LACM.jpg
Skull (LACM 162551) of P. barroni, Natural History Museum of Los Angeles County
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Clade: Pinnipedia
Family: Odobenidae
Genus: Pontolis
True, 1905
Type species
Pontolis magnus
True, 1905
Species
  • P. magnus(True, 1905, type]
  • P. barroniBiewer, Velez-Juarbe & Parham, 2020
  • P. kohnoiBiewer, Velez-Juarbe & Parham, 2020
Synonyms

Pontoleon magnus True, 1905

Pontolis is an extinct genus of large walrus. It contained three species, P. magnus, P. barroni, and P. kohnoi. [1] [2] Like all pinnipeds, Pontolis was a heavily built amphibious carnivore. Pontolis lived along the Pacific coast of North America along what is now the western coasts of California and Oregon between 11.608 and 5.332 million years ago, during the Miocene and Pliocene. [1]

Description

Jaw of P. magnus Pontolis magnus.jpg
Jaw of P. magnus

The skull of Pontolis is 60 cm (24 in) long, surpassing skulls of any other prehistoric pinnipeds and twice as big as the skulls of modern male walruses. [3] This giant species was much larger than modern walrus, though like many other extinct walrus species, its upper canines did not develop into long tusks like those of the modern walrus. Pontolis reached more than 4 m (13 ft) in body length, [4] rivaling the extant southern elephant seal as the largest pinniped [5] and member of the order Carnivora of all time. Weight estimates for Pontolis range between 2,000 to 4,000 kg (4,400 to 8,800 lb). [6]

Related Research Articles

<span class="mw-page-title-main">Carnivora</span> Order of mammals

Carnivora is an order of placental mammals that have specialized in primarily eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species on every major landmass and in a variety of habitats, ranging from the cold polar regions of Earth to the hyper-arid region of the Sahara Desert and the open seas. Carnivorans exhibit a wide array of body plans, varying greatly in size and shape.

<span class="mw-page-title-main">Earless seal</span> Family of mammals

The earless seals, phocids, or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae. They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are mostly confined to polar, subpolar, and temperate climates. The Baikal seal is the only species of exclusively freshwater seal.

<span class="mw-page-title-main">Pinniped</span> Taxonomic group of semi-aquatic mammals

Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae, Otariidae, and Phocidae, with 34 extant species and more than 50 extinct species described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic group. Pinnipeds belong to the suborder Caniformia of the order Carnivora; their closest living relatives are musteloids, having diverged about 50 million years ago.

<span class="mw-page-title-main">Caniformia</span> Suborder of mammals

Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs, bears, raccoons, and mustelids. The Pinnipedia are also assigned to this group. The center of diversification for the Caniformia is North America and northern Eurasia. Caniformia stands in contrast to the other suborder of Carnivora, the Feliformia, the center of diversification of which was in Africa and southern Asia.

<span class="mw-page-title-main">Creodonta</span> Former order of extinct flesh-eating placental mammals

Creodonta is a former order of extinct carnivorous placental mammals that lived from the early Paleocene to the late Miocene epochs in North America, Europe, Asia and Africa. Originally thought to be a single group of animals ancestral to the modern Carnivora, this order is now usually considered a polyphyletic assemblage of two different groups, the oxyaenids and the hyaenodonts, not a natural group. Oxyaenids are first known from the Palaeocene of North America, while hyaenodonts hail from the Palaeocene of Africa.

<i>Ekorus</i> Extinct species of carnivoran

Ekorus ekakeran is a large, extinct mustelid mammal. Fossils, including largely complete skeletons, are known from the late Miocene of Kenya.

<span class="mw-page-title-main">Carnassial</span> Mammal tooth type

Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified fourth upper premolar and the first lower molar. These teeth are also referred to as sectorial teeth.

Potamotherium an extinct genus of caniform carnivoran from the Miocene epoch of France and Germany. It has historically been assigned to the family Mustelidae, but more recent studies suggest that it represents a primitive relative of pinnipeds

<i>Desmatophoca</i> Extinct genus of carnivores

Desmatophoca is an extinct genus of early pinniped that lived during the Miocene, and is named from the Greek "phoca", meaning seal. A taxon of the family Desmatophocidae, it shares some morphological similarities with modern true seals. Two species are recognized: Desmatophoca oregonensis and Desmatophoca brachycephala. Little information exists regarding Desmatophoca, due to the small number of fossil samples obtained and identified.

<i>Imagotaria</i> Extinct genus of carnivores

Imagotaria is an extinct monotypic genus of walrus with the sole species Imagotaria downsi. Fossils of Imagotaria are known from the early late Miocene of California.

<i>Sivatherium</i> Extinct genus of mammals

Sivatherium is an extinct genus of giraffid that ranged throughout Africa and Eurasia. The species Sivatherium giganteum is, by weight, one of the largest giraffids known, and also one of the largest ruminants of all time.

<i>Gomphotaria</i> Extinct genus of carnivores

Gomphotaria is a genus of very large shellfish-eating dusignathine walrus found along the coast of what is now California, during the late Miocene.

<i>Kolponomos</i> Extinct genus of mammals

Kolponomos is an extinct genus of carnivoran mammal that existed in the Late Arikareean North American Land Mammal Age, early Miocene epoch, about 20 million years ago. It was likely a marine mammal. The genus was erected in 1960 by Ruben A. Stirton, a paleontologist at the University of California Museum of Paleontology, Berkeley, for the species K. clallamensis, on the basis of a partial skull and jaw found on the Clallam Formation of the Olympic Peninsula. At the time, Stirton questionably assigned it to Procyonidae, its systematic position remained problematic until the discovery of more fossils including a nearly complete cranium from the original locality of K. clallamensis which helped identify it as part of the group from which pinnipeds evolved.

Neotherium mirum is an extinct species of basal walrus. It was smaller than living forms and it did not have long tusks. Males were larger than females.

<span class="mw-page-title-main">Desmatophocidae</span> Family of mammals

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 no direct modern descendants. Desmatophocids have only been found to live in the North Pacific, with fossils being found in Baja California, California, Oregon, Washington, and Japan.

<span class="mw-page-title-main">Hyaenodonta</span> Extinct order of mammals

Hyaenodonta is an extinct order of hypercarnivorous placental mammals of clade Pan-Carnivora from mirorder Ferae. Hyaenodonts were important mammalian predators that arose during the early Paleocene in Europe and persisted well into the late Miocene.

<i>Archaeodobenus</i> Extinct genus of carnivores

Archaeodobenus is an extinct genus of pinniped that lived during the Late Miocene of what is now Japan. It belonged to the Odobenidae family, which is today only represented by the walrus, but was much more diverse in the past, containing at least 16 genera.

<i>Prototaria</i> Extinct genus of pinniped

Prototaria is an extinct genus of pinniped that lived approximately 15.97 to 13.65 mya during the Middle Miocene in what is now Japan. It belonged to the family Odobenidae, the only extant species of which is the walrus. Members of the genus Prototaria are believed to be the most basal imagotariine pinnipeds.

<i>Protictis</i> Extinct genus of carnivores

Protictis is an extinct paraphyletic genus of placental mammals from extinct subfamily Didymictinae within extinct family Viverravidae, that lived in North America from early Paleocene to middle Eocene.

Osodobenus is an extinct genus of walrus from the Miocene to Pliocene of California. Osodobenus may have been the first tusked walrus and shows several adaptations that suggest it was a suction feeder, possibly even a benthic feeder like modern species. Three skulls are known showing pronounced sexual dimorphism, with the female lacking the same tusks as the male. Only a single species, Osodobenus eodon, is currently recognized.

References

  1. 1 2 "Pontolis". Fossilworks . Retrieved 17 December 2021.
  2. Biewer, Jacob N.; Velez-Juarbe, Jorge; Parham, James F. (1 December 2020). "Insights on the Dental Evolution of Walruses Based on New Fossil Specimens from California". Journal of Vertebrate Paleontology. 40 (5): e1833896. Bibcode:2020JVPal..40E3896B. doi:10.1080/02724634.2020.1833896. ISSN   0272-4634. S2CID   228814992.
  3. Annalisa Berta (2017). The Rise of Marine Mammals: 50 Million Years of Evolution. Johns Hopkins University Press. p. 110. ISBN   9781421423258 . Retrieved 21 August 2022.
  4. Morgan Churchill, Mark T. Clementz, Naoki Kohno. "Cope’s rule and the evolution of body size in Pinnipedimorpha (Mammalia: Carnivora)". Evolution. 2015 Jan;69(1):201-15. doi:10.1111/evo.12560
  5. Xénia Keighley, Morten Tange Olsen, Peter Jordan, Sean P.A. Desjardins (2021). The Atlantic Walrus: Multidisciplinary Insights into Human-Animal Interactions. Charlotte Cockle. p. 17. ISBN   9780128174319 . Retrieved 21 August 2022.{{cite book}}: CS1 maint: multiple names: authors list (link)
  6. Valentin, T. Encyclopedia Largest Prehistoric Animals Vol.1 Vertebrates part1 Mammals ch.1 Carnivores - Hyaenidae, Mustelids and Viverrids Encyclopedia Largest prehistoric animals Vol.1 Vertebrates part1 Mammals ch.1 Carnivores -Mesonychids.