Melville's Whale

Modern sperm whales, the largest predators alive today, have teeth only on the lower jaw and use suction to catch their cephalopod prey.

The discovery of a new fossil species of sperm whale from rocks 15 million years old helps to fill in our understanding of the evolution of sperm whales. The newly discovered whale has jaws that have both upper and lower teeth, teeth that are 36 cm long, giving this fossil predator the biggest bite known. Based on the size of the skull, paleontologists estimate a body length of 13 to 17 meters.

Named Leviathan melvillei, for the novelist Herman Melville, author of Moby Dick, this sperm whale's appearance in the fossil record coincides with diversification of baleen whales. Leviathan melvillei probably fed on baleen whales and as a top predator, helped shape Miocene marine communities.

See summary of the Nature article and more illustrations here.

Filling an empty niche

Despite the occupation by reptiles of almost every ecological niche during the Mesozoic Era, there were no large planktivorous marine reptiles, the niche filled today by baleen whales.

Recent discoveries in museum drawers may hold the answer to this gap in Mesozoic reptile ecology. Fossils that had lain unstudied or incorrectly identified have been newly identified as suspension-feeding pachycormids, a group of giant bony fish.

These fish were previously thought to have been a short-lived group, limited to the Jurassic Period. Mesozoic marine reptiles may have been excluded from the large-bodied, suspension-feeding trophic niche by these supersized fish.

The pachycormids were extinct by the end of the Cretaceous Period, opening up the planktivorous niche to a new group--the whales.

Matt Friedman, et al., 100-Million-year dynasty of giant planktivorous bony fishes in the Mesozoic Seas. Science 327