The overall constellation of traits, including double-rooted teeth, unquestionably identified Basilosaurus as a mammal.



This article was most recently revised and updated by Natural historian Richard Harlan described the fossil in a brief report, published in 1834, in which he named the animal Basilosaurus, or "king lizard." Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
Basilosaurus (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). History at your fingertips Basilosaurus had primitive dentition and skull architecture; the rest of the slender, elongated skeleton was well … Basilosaurids occurred worldwide during most of their history, and important fossils have been recovered in Egypt and the southern United States. Our editors will review what you’ve submitted and determine whether to revise the article.

In 2010, paleontologists found fossils of hundreds of this species, B. isis, in Wadi al Hitan, a site 140 km southwest of Cairo. It shares physical similarities with Orcas and Baleen Whales such as the H…

Basilosaurus ("king lizard") is a genus of early whale that lived 40 to 34 million years ago in the Late Eocene.


Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. It has a long snake-like body that undulates through the seas of the ARK like the sea serpents of folklore and its head is like a crocodile, full of sharp teeth.





Basilosaurus Was Once Mistaken for a Prehistoric Reptile. The first Basilosaurus fossil to come to the attention of scientists was a single vertebra, or back-bone, found in Louisiana in 1832 and sent to the American Philosophical Society in Philadelphia. Basilosaurus, also called Zeuglodon, extinct genus of primitive whales of the family Basilosauridae (suborder Archaeoceti) found in Middle and Late Eocene rocks in North America and northern Africa (the Eocene Epoch lasted from 55.8 million to 33.9 million years ago).





First described in 1834, it was the first archaeocete and prehistoric whale known to science.

By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica.Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. They were originally thought to be of a giant reptile, hence the suffix "-saurus", Ancient Greekfo…

The only known fossils dated to the Oligocene have been found in Peru and New Zealand.



It was first discovered during the 19th century in the United States and was originally thought to have been some kind of prehistoric reptile. In the early 19th century, when the fossil …

While most Basilosaurus bones have been found in Alabama, where the creature is the state fossil, there is a slightly smaller species of Basilosaurus found in Egypt. The Basilosaurus is not actually a reptile despite its name, but a whale or cetacean.

The first fossils were discovered along the Gulf Coast of the United States, along with a few fossils in the eastern U.S., attributed to the type species B. cetoides. Their diversity was highest during the Eocene Epoch.

Alternative Title: Zeuglodon.