Aetiocetus
| Aetiocetus Temporal range: Oligocene |
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| Aetiocetus cotylalveus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Cetacea |
| Suborder: | Mysticeti |
| Family: | †Aetiocetidae |
| Genus: | †Aetiocetus Emlong 1966 |
| Type species | |
| A. cotylalveus, Emlong, 1966 |
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| Species | |
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Aetiocetus is an extinct genus of baleen whale that lived 25 million years ago, in the Oligocene period. Its fossils have been found in the North Pacific,[1] around Oregon. It was first named by Douglas Emlong in 1966 and currently contains four species, A cotylalveus, A. polydentatus, A. tomitai, and A. weltoni.
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[edit] Description
Aetiocetus is a transitional fossil between early whales and the modern whales, its blowhole being located halfway up its snout rather than at the top of its head.[2] It is also one of the earliest-known baleen whales.[3] The genus, though more cranially reminiscent of archaic whales, with its pronounced snout and flat cranium,[4] had a loose jaw like later baleen whales.[3] Aetiocetus skulls have also shown that the animal bore a full set of teeth,[3][5] as well as baleen.[4][6] The skulls contain about forty-four teeth,[7] which consist of cusped molars, curved canines, and incisors.[4] Aetiocetus most likely fed on fish and crustaceans.[4]
Douglas Emlong originally classified it in the extinct whale suborder Archaeoceti,[8][9] because of its teeth. However, when Van Valen analyzed it in 1968, he moved the genus to the suborder Mysticeti due to its derived pattern of bone telescoping.[9]
[edit] Species
- A. cotylalveus, type species, Emlong, 1966
- A. polydentatus, Barnes, Kimura, Furusawa & Sawamura, 1995
- A. tomitai, Barnes, Kimura, Furusawa & Sawamura, 1995
- A. weltoni, Barnes, Kimura, Furusawa & Sawamura, 1995. An analysis of this species revealed similar palatal nutrient foramina to those that house vessels that feed modern genera of mysticetes.[6]
[edit] Sister Taxa
[edit] References
- ^ "The Origins and Adaptations of Mysticetes". Robert Ewan Fordyce. 1998-06-07. Archived from the original on 2008-06-28. http://web.archive.org/web/20080628030851/http://www.otago.ac.nz/geology/features/paleontology/whales.htm. Retrieved 2008-06-29.
- ^ "Lines of Evidence:Transitional Forms (1 of 2)". Understanding Evolution. Berkeley University. http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml. Retrieved 2008-04-26.
- ^ a b c "Whale Glossary - Section A.". www.enchantedlearning.com. http://www.enchantedlearning.com/subjects/whales/glossary/. Retrieved 2008-06-29.
- ^ a b c d Neptune's Ark: From Ichthyosaurs to Orcas By David Rains Wallace. Published 2007 University of California Press. ISBN 0-520-24322-6 Retrieved on June 29th, 2008.
- ^ "Developmental biology, page 2". evolution.berkely.edu. http://evolution.berkeley.edu/evosite/lines/IICdevelopmental2.shtml. Retrieved 2008-06-29.
- ^ a b "Stepwise Evolution of Filter Feeding in Baleen Whales". www.sicb.org. 2006. http://www.sicb.org/meetings/2006/schedule/abstractdetails.php3?id=654. Retrieved 2008-06-29.
- ^ McGraw-Hill Encyclopedia of Science & Technology; page 490. By Sybil P. Parker, published 1997; McGraw-Hill. ISBN 0-07-911504-7 Retrieved on June 29th, 2008.
- ^ The Rise of Placental Mammals; page 236. By Kenneth David Rose and J. David Archibald. Published 2005 JHU Press. ISBN 0-8018-8022-X Retrieved on June 29th, 2008.
- ^ a b Marine Mammal Biology: An Evolutionary Approach by A. Rus Hoelzel. Published 2002, Blackwell Publishing. ISBN 0-632-05232-5 Retrieved on June 29th, 2008.
[edit] Further reading
- At the Water's Edge : Fish with Fingers, Whales with Legs, and How Life Came Ashore but Then Went Back to Sea by Carl Zimmer ISBN 0-684-83490-1
- Marine Mammals: Evolutionary Biology by Annalisa Berta, James L. Sumich, and Kit M. Kovacs
- In Search of Ancient Oregon: A Geological and Natural History by Ellen Morris Bishop
- Whales of the West Coast by David A E Spalding
- Encyclopedia of Marine Mammals by William F. Perrin, Bernd Wursig, and J. G.M. Thewissen
- Aquagenesis: The Origin and Evolution of Life in the Sea by Richard Ellis
- The New Encyclopaedia Britannica By Encyclopædia Britannica, inc, Robert McHenry ISBN 0-85229-633-9
- Grzimek's Animal Life Encyclopedia by Bernhard Grzimek, Neil Schlager, Donna Olendorf, and Melissa McDade, of the American Zoo and Aquarium Association. ISBN 0-7876-5791-3
[edit] External links
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