Mississippi State Fossil

Prehistoric Whales

(Basilosaurus cetoides & Zygorhiza kochii)

Adopted on March 26, 1981.

A Senate Concurrent Resolution, designating these prehistoric whales, Basilosaurus cetoides Zygorhiza kochii, as the state fossils, was adopted on March 26, 1981 with Senate Concurrent Resolution No. 557.

Basilosaurus is the larger and better-known of the two state fossils. It had a small head and a narrow body 50 - 80 feet long, giving it the look of a "sea serpent." The first specimen of this whale was found in 1832 along the Ouachita River, and since that time specimens have turned up regularly in Mississippi, Louisiana, and Alabama. Zygorhiza was a smaller whale, reaching only 20 feet, and had a more whale-like body form. The first well-preserved specimens of Zygorhiza were found on the Gulf Coastal Plain in the late 1800s, and a nearly complete skeleton was excavated near Tinsley in 1971.

Zygorhiza kochii was an archaeocete, a forerunner of the modern toothed whales (e.g., sperm whales, killer whales, porpoises, etc.) which lived during the Eocene epoch (approximately 37,000,000 to 56,000,000 years ago). Its fossilized remains are very rarely found in southeastern North Carolina. It was an impressive predator in those early oceans, reaching almost 20 feet in length. The largest teeth (the second and third premolars) are 2 - 2½ inches wide in a mature individual.