from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a genus of extinct whales with serrated teeth, belonging to the Squalodontidae.
from the GNU version of the Collaborative International Dictionary of English
- n. A genus of fossil whales belonging to the Phocodontia; -- so called because their teeth are serrated, like a shark's.
Squalus ("a genus of sharks") + Ancient Greek ὀδών (odōn, "tooth"), alternative form of ὀδούς (odous, "tooth"). (Wiktionary)
The one on the right is Ed's, devolving (apparently) from a squalodon to a pakicetus.