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Ross seal
The Ross seal (''Ommatophoca rossii'') is a true seal (family Phocidae) with a range confined entirely to the pack ice of Antarctica. It is the only species of the genus ''Ommatophoca''. First described during James Clark Ross' British Antarctic Expedition in 1841, it is the smallest, least abundant and least well known of the Antarctic pinnipeds. Its distinctive features include disproportionately large eyes, whence its scientific name (''Ommato-'' meaning "eye", and ''phoca'' meaning "seal"), and complex, trilling and siren-like vocalizations.
==Taxonomy and evolution==
The Ross seal shares a recent common ancestor with the other Antarctic seals, which are together known as the lobodontine seals. These include the crabeater seal (''Lobodon carcinophaga''), leopard seal (''Hydrurga leptonyx'') and Weddell seal (''Leptonychotes weddelli''). These species, collectively belonging to the seal tribe Lobodontini, share teeth adaptations, including lobes and cusps useful for straining smaller prey items out of the water column. The ancestral Lobodontini likely diverged from its sister clade, ''Mirounga'' (elephant seals) in the late Miocene to early Pliocene, when they migrated southward and diversified rapidly in relative isolation around Antarctica.〔 However, the only fossil Ross seals so far known date from much later, during the early Pleistocene of New Zealand.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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