Aetiocetus
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| Aetiocetus Fossil range: Oligocene |
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 Aetiocetus cotylalveus
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| †A. cotylalveus, Emlong, 1966 |
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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 Emlong in 1966 and contains four species, A cotylalveus, A. polydentatus, A. tomitai, and A. weltoni.
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[edit] Jaw
Aetiocetus is a transitional fossil between Pakicetus and the modern gray whale. [2] It is the earliest-known baleen whale.[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]
Emlong originally classified it as an Archaeoceti,[8][9] because of its teeth. However, when Van Valen analyzed it in 1968, he renamed it under Mysticete because of its derieved pattern of bone telescoping.[9]
[edit] Species
- Aetiocetus cotylalveus, type species, Emlong, 1966
- Aetiocetus polydentatus, Barnes, Kimura, Furusawa & Sawamura, 1995
- Aetiocetus tomitai, Barnes, Kimura, Furusawa & Sawamura, 1995
- Aetiocetus weltoni, Barnes, Kimura, Furusawa & Sawamura, 1995. An analysis of this species revealed that there were similar palatal nutrient foramina to those which house vessels which feed modern genuses of Mysticetes.[6]
[edit] References
- ^ "The Origins and Adaptations of Mysticetes". Robert Ewan Fordyce. 1998-06-07. http://www.otago.ac.nz/geology/features/paleontology/whales.htm. Retrieved on 2008-06-29.
- ^ "Lines of Evidence:Transitional Forms (1 of 2)". Understanding Evolution. Berkeley University. http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml. Retrieved on 2008-04-26.
- ^ a b c "Whale Glossary - Section A.". www.enchantedlearning.com. http://www.enchantedlearning.com/subjects/whales/glossary/. Retrieved on 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 0520243226 Retrieved on June 29th, 2008.
- ^ "Developmental biology, page 2". evelution.berkely.edu. http://evolution.berkeley.edu/evosite/lines/IICdevelopmental2.shtml. Retrieved on 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 on 2008-06-29.
- ^ McGraw-Hill Encyclopedia of Science & Technology; page 490. By Sybil P. Parker, published 1997; McGraw-Hill. ISBN 0079115047 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 080188022X Retrieved on June 29th, 2008.
- ^ a b Marine Mammal Biology: An Evolutionary Approach by A. Rus Hoelzel. Published 2002, Blackwell Publishing. ISBN 0632052325 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 0684834901
- 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 Encyclopaedia Britannica, inc, Robert McHenry ISBN 0852296339
- Grzimek's Animal Life Encyclopedia by Bernhard Grzimek, Neil Schlager, Donna Olendorf, and Melissa McDade, of the American Zoo and Aquarium Association. ISBN 0787657913
- Neptune's Ark: From Ichthyosaurs to Orcas by David Rains Wallace. ISBN 9780520243224
[edit] External links
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