Extinct Shark’s Teeth Had Their Own Needle-Like Fangs

Paleontologists have described a new species of the extinct lamniform shark genus Palaeohypotodus based on 17 fossilized teeth found in Alabama, the United States.

“Palaeohypotodus is an extinct lamniform shark genus that has a purported temporal range extending from the Late Cretaceous (Maastrichtian) to the Late Eocene (Priabonian), and isolated teeth have been reported from widely disparate localities from around the world,” said Dr. Jun Ebersole, director of collections at the McWane Science Center, and his colleagues.

“Three species are recognized within the genus, including the Cretaceous Palaeohypotodus bronni, and the Paleogene Palaeohypotodus volgensis and Palaeohypotodus rutoti.”

“These species are characterized by robust teeth having a combination of erect to strongly distally hooked crown, smooth cutting edges, one or more pairs of lateral cusplets, and distinctive plications along the labial crown foot.”

“Palaeohypotodus is known primarily by isolated teeth, but at least one partially associated skeleton has been reported.”

The newly-identified species, Palaeohypotodus bizzocoi, lived approximately 65 million years ago (Paleocene period).

A collection of 17 teeth belonging to the species was recently found in the historical collections of the Geological Survey of Alabama in Tuscaloosa.

The specimens were derived from the Porters Creek Formation of Wilcox County in Alabama.

“A few years ago, I was looking through the historical fossil collections at the Geological Survey in Alabama and came across a small box of shark teeth that were collected over 100 years ago in Wilcox County,” Dr. Ebersole said.

“Having documented hundreds of fossil fish species over the last decade, I found it puzzling that these teeth were from a shark that I didn’t recognize.”

Palaeohypotodus bizzocoi was a leading predator during the time when the oceans were recovering from the end-Cretaceous mass extinction.

“In Alabama, much of the southern half of the state was covered by shallow tropical to sub-tropical ocean during the Paleocene,” said Dr. T. Lynn Harrell, Jr., a paleontologist and fossil collections curator at the Geological Survey of Alabama.

“This time period is understudied, which makes the discovery of this new shark species that much more significant.”

“Shark discoveries like this one give us tremendous insights into how ocean life recovers after major extinction events and also allows us to potentially forecast how global events, like climate change, affect marine life today.”

As part of their study, the authors compared the fossil teeth of Palaeohypotodus bizzocoi to those of various living sharks, like the great white shark and mako sharks.

“By studying the jaws and teeth of living sharks, it allowed us to reconstruct the dentition of this ancient species and showed that it had a tooth arrangement that differed from any living shark,” said Dr. David Cicimurri, curator of natural history at South Carolina State Museum.

A paper describing the discovery was published in the journal Fossil Record.

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J.A. Ebersole et al. 2024. A new species of Palaeohypotodus Glickman, 1964 (Chondrichthyes, Lamniformes) from the lower Paleocene (Danian) Porters Creek Formation, Wilcox County, Alabama, USA. Fossil Record 27 (1): 111-134; doi: 10.3897/fr.27.e112800