Aetiocetus

Taxobox
name="Aetiocetus"
fossil_range=Oligocene

---

image_width = 290px
image_caption="Aetiocetus cotylalveus"
regnum=Animalia
phylum=Chordata
classis=Mammalia
ordo=Cetacea
familia=†Aetiocetidae
genus=†"Aetiocetus"
genus_authority=Emlong 1966
type_species= †"A. cotylalveus", Emlong, 1966
subdivision_ranks=Species
subdivision=
* †"A. cotylalveus"
* †"A. polydentatus"
* †"A. tomitai"
* †"A. weltoni"

"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,cite web |url=http://www.otago.ac.nz/geology/features/paleontology/whales.htm |title=The Origins and Adaptations of Mysticetes |publisher=Robert Ewan Fordyce |date=1998-06-07 |accessdate=2008-06-29] around Oregon. It was first named by Emlong in 1966 and contains four species, "A cotylalveus", "A. polydentatus", "A. tomitai", and "A. weltoni".

Jaw

"Aetiocetus" is a transitional fossil between "Pakicetus" and the modern gray whale. [cite web |url=http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml |title=Lines of Evidence:Transitional Forms (1 of 2) |accessdate=2008-04-26|work=Understanding Evolution |publisher=Berkeley University ] It is the earliest-known baleen whale.cite web |url=http://www.enchantedlearning.com/subjects/whales/glossary/ |title=Whale Glossary - Section A. |publisher=www.enchantedlearning.com |accessdate=2008-06-29] The genus, though more cranially reminiscent of archaic whales, with its pronounced snout and flat cranium,"Neptune's Ark: From Ichthyosaurs to Orcas" By David Rains Wallace. Published 2007 University of California Press. ISBN 0520243226 Retrieved on June 29th, 2008.] had a loose jaw like later baleen whales. "Aetiocetus" skulls have also shown that the animal bore a full set of teeth, [cite web |url=http://evolution.berkeley.edu/evosite/lines/IICdevelopmental2.shtml |title=Developmental biology, page 2 |publisher=evelution.berkely.edu |accessdate=2008-06-29] as well as baleen.cite web |url=http://www.sicb.org/meetings/2006/schedule/abstractdetails.php3?id=654 |title=Stepwise Evolution of Filter Feeding in Baleen Whales |publisher=www.sicb.org |date=2006 |accessdate=2008-06-29] The skulls contain about forty-four teeth, ["McGraw-Hill Encyclopedia of Science & Technology"; page 490. By Sybil P. Parker, published 1997; McGraw-Hill. ISBN 0079115047 Retrieved on June 29th, 2008.] which consist of cusped molars, curved canines, and incisors. "Aetiocetus" most likely fed on fish and crustaceans.

Emlong originally classified it as an "Archaeoceti", ["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.] "Marine Mammal Biology: An Evolutionary Approach" by A. Rus Hoelzel. Published 2002, Blackwell Publishing. ISBN 0632052325 Retrieved on June 29th, 2008.] 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.

pecies

*"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".

References

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

External links

* [http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=36654 The Paleobiology Database]
* [http://www.archaeocete.org/EAT%202005%20Abstracts.pdf www.archaeocete.org]
* [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1639514 www.pubmedcentral.nih.gov]