The Cetacea were thought to be most closely related to the Perissodactyla or the oddtoed u

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The Cetacea were thought to be most closely related to the Perissodactyla or the odd-toed ungulates which include the horse, the tapir and the rhinoceros (ungulate = approx. hoofed, plant-eating mammals, but more accurately approximates to a group showing taxanomic and ecologic adaptions to plant eating). However molecular immunodifusion, protien sequence and cxytochrome b sequence results suggested a link with the Artiodacyla or even-toed ungulates (pig, camal, hippo, deer, cow etc.). In 1985-88, Eocene whales (archaeocetes) were found in which the skull and dental structure was very like the mesonychid condylarths (primative artiodactyls). In 1990 a late Middle Eocene whale was described with complete (if vestigial) hindlimbs [1]. The whale, _Basilosaurus_ has a paraxonic arrangement of digits - where the digits symmetrically extend about a plane between digits III and IV. This is very similar to the condition in mesonychid condylarths and paraxonic artiodactylans. Thus the fossil record confirms the inferences gained from molecular data on the relationship between the cetaceans and the ungulates. The nearest reletive to the whale is within the Artiodacyla and could be any of a number of candidates - I have no more detailed information than that (so it could be the pig), except that it could not be the camal - that group does not have the paraxonic condition and was already established by the Eocene. [1] Science (1990) 249, p.154-157


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