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Species of the infraorder Cetacea A phylogenetic tree showing the relationships among cetacean families. [1]The evolution of cetaceans is thought to have begun in the Indian subcontinent from even-toed ungulates (Artiodactyla) 50 million years ago (mya) and to have proceeded over a period of at least 15 million years. [2]
Its closest modern relative is the South Asian river dolphin ... Many of the fresh-water dolphins are differentiated phylogenetically very well, while the argument of ...
Although it has morphological similarities with the false killer whale, the pygmy killer whale and the pilot whales, a study of cytochrome b gene sequences indicates that its closest extant relatives are the snubfin dolphins of the genus Orcaella. [18]
Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla , which consists of even-toed ungulates . Their closest non-cetacean living relatives are the hippopotamuses , from which they and other cetaceans diverged about 54 million years ago.
The family Balaenidae, the right whales, contains two genera and four species. All right whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; and long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes.
Odontoceti (toothed whales, dolphins, and porpoises) Superfamily Delphinoidea (dolphins, arctic whales, porpoises, and relatives) Family Delphinidae, 38 species (dolphins, killer whales, and relatives) Family Monodontidae, 2 species (beluga and narwhal) Family Phocoenidae, 6 species ; Superfamily Physeteroidea (sperm whales)
Cetacea (/ s ɪ ˈ t eɪ ʃ ə /; from Latin cetus 'whale', from Ancient Greek κῆτος () 'huge fish, sea monster') [3] is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises.
The name Whippomorpha is a combination of English (wh[ale] + hippo[potamus]) and Greek (μορφή, morphē = form). [2]Some attempts have been made to rename the suborder Cetancodonta, due to the misleading utilization of the suffix -morpha for a crown group, [6] as well as the risk of confusion with the clade Hippomorpha (which consists of equid perissodactyls); [7] however Whippomorpha ...