Temporal range: Late Eocene
|A skull of Basilosaurus cetoides|
Basilosaurus is a genus of cetacean that lived from 40 to 34 million years ago in the Late Eocene. The first Basilosaurus fossils were found in Louisiana, USA, but another species was soon discovered preserved in large numbers in the Fayum deposits of Egypt.
The first fossil of B. cetoides was discovered in the United States and was initially believed to be some sort of reptile, hence the suffix -"saurus", but it was later found to be a marine mammal. Richard Owen wanted to rename the creature Zeuglodon ("yoked tooth"), but by taxonomic rules the creature's first name remained permanent. Fossils of B. isis have been found in Egypt and Jordan.
Far from being a marine reptile, Basilosaurus is a stage in the evolution of whales. At 40–65 ft (12–20 m), Basilosaurus cetoides was one of the largest oceanic animals of its time. Basilosaurus went extinct during the Eocene Extinction.
References[change | change source]
- "Basilosaurus". BBC Nature. Retrieved August 2013. Check date values in:
- Zalmout I.S; Mustafa H.A. & Gingerich P.D. 2000. Priabonian Basilosaurus isis (Cetacea) from the Wadi Esh-Shallala Formation: first marine mammal from the Eocene of Jordan. Journal of Vertebrate Paleontology 20 (1): 201–204. 
- Gingerich P.D. 2007. Early evolution of whales: a century of research in Egypt. In Fleagle J.G; Gilbert, Christopher C. & Elwyn Simons (eds) A search for origins. New York: Springer. pp. 107–124. ISBN 978-0-387-73896-3. OCLC 233971398. Retrieved August 2013.