Archaeoceti
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| Archaeoceti Temporal range: Eocene–Oligocene |
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| Cynthiacetus and Ambulocetus skeletons | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Cetacea |
| Suborder: | †Archaeoceti Flower, 1883 |
| Families and Clades | |
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see text |
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Archaeocetes, or "ancient whales", are a paraphyletic group of cetaceans that gave rise to the modern cetaceans.
The archaeocetes were once thought to have evolved from the mesonychids, based on dental characteristics. However, recent studies in molecular genetics and non-dental morphology show that the first whales or the archaeoceti most likely evolved from artiodactyls; genetic evidence indicates that their closest living relatives are the family Hippopotamidae which includes the modern hippopotamus. The ancestors of archaeocetes probably diverged from the other artiodactyls around the time of the Cretaceous–Tertiary extinction event.
Most archaeocetes had hind limbs, suggesting that they were fully terrestrial. As the Eocene epoch progressed, the archaeocetes became less terrestrial and more aquatic. Before the Eocene epoch came to an end, one group of archaeocetes, the basilosaurids, gave rise to early modern cetaceans. The archaeocetes suffered a heavy loss of genera during the Eocene-Oligocene extinction event, but some species survived into the Oligocene. The last archaeocete, which was probably a basilosaurid, became extinct in the Oligocene. They may have become extinct from a combination of competition and climate change.
Contents |
[edit] Taxonomy
Archaeoceti includes five families:[1]
- Order Cetacea
- Suborder Archaeoceti
- Family Pakicetidae
- Genus Pakicetus
- Genus Nalacetus
- Genus Ichthyolestes
- Family Ambulocetidae
- Genus Ambulocetus
- Genus Gandakasia
- Genus Himalayacetus
- Family Remingtonocetidae
- Genus Andrewsiphius
- Genus Attockicetus
- Genus Dalanistes
- Genus Kutchicetus
- Genus Remingtonocetus
- Family Protocetidae
- Subfamily Georgiacetinae
- Genus Babiacetus
- Genus Carolinacetus
- Genus Eocetus
- Genus Georgiacetus
- Genus Natchitochia
- Genus Pappocetus
- Subfamily Makaracetinae
- Genus Makaracetus
- Subfamily Protocetinae
- Genus Artiocetus[2]
- Genus Crenatocetus
- Genus Gaviacetus
- Genus Indocetus
- Genus Maiacetus
- Genus Protocetus
- Genus Qaisracetus
- Genus Rodhocetus
- Genus Takracetus
- Subfamily Georgiacetinae
- Family Basilosauridae
- Subfamily Basilosaurinae
- Genus Basilosaurus
- Genus Basiloterus
- Subfamily Dorudontinae
- Genus Ancalecetus
- Genus Chrysocetus
- Genus Cynthiacetus
- Genus Dorudon
- Genus Saghacetus
- Genus Zygorhiza
- Subfamily Kekenodontinae
- Genus Kekenodon
- Genus Phococetus
- Subfamily Stromeriinae
- Genus Stromerius[3]
- Subfamily Basilosaurinae
- Family Pakicetidae
- Suborder Archaeoceti
[edit] Phylogeny
| Cetartiodactyla |
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[edit] See also
[edit] References
- ^ Kenneth David Rose (2006). The Beginning of the Age of Mammals. JHU Press. p. 273. ISBN 9780801884726. http://books.google.com.ph/books?id=3bs0D5ix4VAC&lpg=PA273&dq=Ambulocetidae&pg=PA273#v=onepage&q=Ambulocetidae&f=false.
- ^ Gingerich, D.; Haq, U.; Zalmout, S.; Khan, H.; Malkani, S. (Sep 2001). "Origin of whales from early artiodactyls: hands and feet of Eocene Protocetidae from Pakistan". Science 293 (5538): 2239–2242. Bibcode 2001Sci...293.2239G. doi:10.1126/science.1063902. ISSN 0036-8075. PMID 11567134.
- ^ Philip D. Gingerich (2007). "Stromerius nidensis, new archaeocete (Mammalia, Cetacea) from the Upper Eocene Qasr El-Sagha Formation, Fayum, Egypt". Contributions from the Museum of Paleontology 31 (13): 363–378. http://deepblue.lib.umich.edu/bitstream/2027.42/57499/1/Vol%2031%20No%2013%20final%2012-19-07.pdf.
