| 翻訳と辞書 |
| Pygmy right whale ： ウィキペディア英語版 |
Pygmy right whale
The pygmy right whale (''Caperea marginata'') is a member of the cetotheres, a family of baleen whales, which until 2012 were thought to be extinct; previously ''C. marginata'' was considered the sole member of the family Neobalaenidae. First described by John Edward Gray in 1846, it is the smallest of the baleen whales, ranging between and in length and 3,000 and 3,500 kg in mass. Despite its name, the pygmy right whale may have more in common with the gray whale and rorquals than the bowhead and right whales.〔
The pygmy right whale is found in the Southern Ocean in the lower reaches of the Southern Hemisphere, and feeds on copepods and euphausiids. Little is known about its population or social habits. Unlike most other baleen whales, it has rarely been subject to exploitation.
==Taxonomy==
During the 1839-43 voyage of James Clark Ross naturalists found bones and baleen plates resembling a smaller version of the right whale. In his ''Zoology of the Voyage of HMS Erebus and Terror'' (1846), John Edward Gray described the new species, naming it ''Balaena marginata''. In 1864 Gray established a new genus (''Caperea'') after receiving a skull and some bones of another specimen. Six years later, in 1870, he added the name ''Neobalaena''. He soon realized the three species were one and the same: ''Caperea marginata''〔Cousteau, Jacques, ''Whales'' (1986), p. 70.〕 (''caperea'' means "wrinkle" in Latin, "referring to the wrinkled appearance of the ear bone"; while ''marginata'' translates to "enclosed with a border", which "refers to the dark border around the baleen plates of some individuals").〔Reeves, Randall, ''Guide to Marine Mammals of the World'' (2002), p. 202.〕 In research findings published on December 18, 2012, paleontologist Felix Marx compared the skull bones of pygmy right whales to those of other extinct cetaceans, finding it to be a close relative to the Cetotheriidae, making the pygmy right whale a living fossil.〔
In 2012, Italian palaeontologist Michelangelo Bisconti described ''Miocaperea pulchra'', a first fossil pygmy right whale from Peru. This new genus differs from the living genus in some cranial details, but Bisconti's study confirmed the monophyly of Neobalaenidae and he concluded that the rorqual-like features in ''C. marginata'' must be the result of parallel evolution. The presence of a fossil neobalaenid some north of the known range of ''C. marginata'', suggests that environmental change has caused a southern shift in neobalaenid distribution. A second, undescribed species was tentatively assigned to Neobalaenidae in 2012.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Pygmy right whale」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|