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Odobenidae
Odobenidae is a family of pinnipeds. The only living species is the walrus (''Odobenus rosmarus''). In the past, however, the group was much more diverse, and includes more than a dozen fossil genera. Taxonomy All genera, except ''Walrus, Odobenus'', are extinct. *†''Archaeodobenus'' *†''Prototaria'' *†''Proneotherium'' *†''Nanodobenus'' *†''Neotherium'' *†''Imagotaria'' *†''Kamtschatarctos'' *†''Pelagiarctos'' *†''Pontolis'' *†''Pseudotaria'' *†''Titanotaria'' *Clade Neodobenia **†''Gomphotaria'' **Subfamily Dusignathinae ***†''Dusignathus'' **Subfamily Odobeninae ***†''Aivukus'' ***†''Ontocetus'' ***†''Pliopedia'' ***†''Protodobenus'' ***†''Valenictus'' ***''Walrus, Odobenus'' In re-analyzing ''Pelagiarctos'', Boessenecker et al. (2013) proposed the phylogenetic relationships of Odobenidae as follows (this analysis excluded ''Archaeodobenus, Titanotaria, Nanodobenus,'' and ''Pliopedia;'' and included ''Enaliarctos, Pteronarctos, Allodesmus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinniped
Pinnipeds (pronounced ), 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 (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). There are 34 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). Pinnipeds belong to the order Carnivora; their closest living relatives are musteloids (weasels, raccoons, skunks, and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal seal to the and southern elephant seal male, which is also the largest member of the order Carnivora. Several species exh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odobenus
The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and their considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walruses live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic bivalve mollusks to eat. Walruses are relatively long-lived, social animals, and they are considered to be a " keystone spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large pinniped, flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the family (biology), family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and their considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walruses live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic zone, benthic bivalvia, bivalve mollusks to eat. Walruses are relatively long-lived, social animals, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large pinniped, flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the family (biology), family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and their considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walruses live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic zone, benthic bivalvia, bivalve mollusks to eat. Walruses are relatively long-lived, social animals, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanodobenus
''Nanodobenus'' is an extinct genus of pinniped that lived approximately 15.97 to 7.246 mya during the Miocene in what is now Baja California Sur, Mexico. It belonged to the family Odobenidae, the only extant species of which is the walrus. Discovery ''N. arandai'' is known from a partially complete left mandible and a right calcaneum bone, discovered in the Torgugas Formation in Mexico. Description ''Nanodobenus'' were 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. Despite the general increase in body size of odobenids from the Miocene to Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeodobenus
''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. Unlike the modern walrus, ''Archaeodobenus'' did not have tusks but instead had canines of moderate size, and looked more like a sea lion. Discovery The first known specimen was collected in 1977 from the Ichibangawa Formation in Tobetsu Town on the island of Hokkaido. The specimen consists of a partial skull, vertebrae, and limb bones, and was made the holotype specimen of the new genus and species ''A. akamatsui'' by the Japanese palaeontologists Yoshihiro Tanaka and Naoki Kohno in 2015. The generic name consists of ''archaio-'', the Greek word for ancient, and the generic name of the walrus, ''Odobenus''; in full, "ancient walrus." The specific name honors Morio Akamatsu, a curator of the Hokkaido Museum. The ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prototaria
''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. Unlike their closest living relative, the walrus, members of ''Prototaria'' were primarily piscivorous carnivores. Description ''Prototaria'' were more similar in appearance to modern fur seals and sea lions than walruses. They did not have long tusks as walruses do, and were more slender. Fossils ascribed to ''Prototaria'' exhibit some autapomorphies, including: a large antorbital process and orbit, and a relatively narrow intertemporal region of the skull. ''P. planicephala'' has a wider rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proneotherium
''Proneotherium'' is an extinct genus of pinniped that lived approximately 20.43 to 15.97 mya 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. Description ''Proneotherium'' were 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. This likely represents the slow shift from a piscivorous diet to the mollusk-based d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valenictus Chulavistensis
''Valenictus'' is an extinct genus of Odobenidae from the Pliocene of California. Description ''Valenictus'' is related to the modern-day walrus, but lacked all teeth both in the lower and upper jaw except for the two tusks Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with pigs and walruses, or, in the case of elephants, elongated incisors. Tusks share .... References Pliocene extinctions Prehistoric pinnipeds of North America Odobenids Prehistoric carnivoran genera Pliocene pinnipeds Pliocene mammals of North America Fossil taxa described in 1961 {{paleo-carnivora-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontocetus
''Ontocetus'' is an extinct genus of walrus, an aquatic carnivoran of the family Odobenidae, endemic to coastal regions of the southern North Sea and the southeastern coastal regions of the U.S. during the Miocene-Pleistocene. It lived from 13.6 mya—300,000 years ago, existing for approximately . Taxonomy The type species, ''Ontocetus emmonsi'', was named by Joseph Leidy in 1859 on the basis of a single tusk-like tooth (USNM 329064) collected by Ebenezer Emmons from the early Pliocene (Zanclean) Yorktown Formation of North Carolina. In the meantime, marine mammals fossils were being unearthed in Neogene deposits in the vicinity of Antwerp, Belgium as well as Suffolk, England. One of these fossils was identified as an odobenid and named ''Alachtherium cretsii.'' in 1867. An isolated tooth (RBINS 2892) was named ''Trichechodon koninckii'' in 1871. The fossils from Suffolk were named ''Trichechodon huxleyi'' in 1865. For decades, however, ''Ontocetus'' was tossed aside as a phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erignathus
The bearded seal (''Erignathus barbatus''), also called the square flipper seal, is a medium-sized pinniped that is found in and near to the Arctic Ocean. It gets its generic name from two Greek words (''eri'' and ''gnathos'') that refer to its heavy jaw. The other part of its Linnaean name means bearded and refers to its most characteristic feature, the conspicuous and very abundant whiskers. When dry, these whiskers curl very elegantly, giving the bearded seal a "raffish" look. Bearded seals are the largest northern phocid. They have been found to weigh as much as with the females being the largest. However, male and female bearded seals are not very dimorphic. The only member of the genus ''Erignathus'', the bearded seal is unique in that it is an intermediate. Bearded seals belong to the family Phocidae which contains two subfamilies: Phocinae and Monachinae. The bearded seal possesses characteristics of both of these subfamilies. Fossils first described in 2002 indicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmatophoca
''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.Ray, C. (1976). Fossil Marine Mammals of Oregon. ''Systematic Zoology, 25''(4), 420-436. Two species are recognized: ''Desmatophoca oregonensis'' and ''Desmatophoca brachycephala''Berta, A. (1994). A New Species of Phocoid Pinniped Pinnarctidion from the Early Miocene of Oregon. ''Journal of Vertebrate Paleontology, 14''(3), 405-413.''.'' Little information exists regarding ''Desmatophoca'', due to the small number of fossil samples obtained and identified. Unlike modern pinnipeds, ''Desmatophoca'' did not survive into the Holocene. There is some scientific debate as to whether any ''Desmatophoca'' species may have been present in the Oligocene, but without fossil samples obtained from this era, this is based primarily on conjecture. All sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
