Maiacetus Temporal range: Middle Eocene |
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Maiacetus skeleton cast in the Smithsonian Museum | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Cetacea |
Suborder: | Archaeoceti |
Family: | Protocetidae |
Subfamily: | Protocetinae |
Genus: | Maiacetus Gingerich et al., 2009 |
Species | |
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Maiacetus ("mother whale") is a genus of early middle Eocene (ca. 47.5 mya) cetacean from Pakistan.
The genus contains a single species Maiacetus inuus, first described in 2009 on the basis of two specimens, including a specimen which has been interpreted as a pregnant female and its fetus.[1] This represents the first description of a fetal skeleton of an archaeocete. The position of the fetus (head-first) suggests that these whales gave birth on land.[2] Whales generally give birth tail first, while all land mammals give birth head first. That the Maiacetus should give birth on land is not so implausible because this whale is semiaquatic or amphibious. Maiacetus represents the transition of land mammals back to the oceans where these animals were living on the land-sea interface and going back and forth.[3]
However, J. G. M. Thewissen, discoverer of Ambulocetus, has questioned these conclusions, suggesting that the smaller skeleton could be a partially digested meal. Even if the small skeleton is a fetus, Thewissen writes that it may not have been preserved in its normal in-vivo position.[4]
This species is medium-sized with a skeleton 2.6 m in length and an estimated weight of 280–390 kg.