Cookiecutter Shark Tooth (Posterior)

Taxonomy

Cookiecutter Shark

Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Squaliformes
Family: Dalatiidae
Genus: Isistius
Species: Isistius triangulus
Author Citation T.N. Gill, 1865

Geological Time Scale

Eon: Phanerozoic
Era: Cenozoic
Period: Neogene
Epoch: Pliocene

Stratigraphy

Tamiami Formation

Provenance

Date Collected: 07/23/2017
Acquired by: Field Collection

Dimensions

Width: 4.0 mm
Height: 3.5 mm
Thickness: 0.5 mm

Location

"Cookiecutter Creek"
Sarasota County
Florida
United States

• cookiecutter
• florida
• isistius
• posterior

Comments

This tooth is a lower from the final tooth position (most posterior) on the left side as indicated by the bulge on one side of the tooth and lack of overlapping facet. The lingual face of the tooth is shown in the photo as indicated by the distinct delineation of the crown enamel and the root (less distinct on the labial surface). Teeth in a more anterior position have overlapping facets on both edges (with the symphyseal having both facets on the lingual face).

 

The stratigraphic information for this locality is questionable and so is specified vaguely. The environment is marine shell hash that may span late Miocene-Pleistocene. Dr. Richard C. Hulbert, Jr. from FLMNH had this to say about the locality:

 

There are two “formations” found near the surface in that area of the state.  One is the middle to late Miocene Peace River Formation.  The other “formation” possible is has been informally called the Okeechobee Formation by Tom Scott, and consists of the sandy shell beds formerly called the Caloosahatchee, Bermont, and Fort Thompson formations.  On the geologic map of Florida published by the state’s geological survey it is not designated a formal name and is instead listed as Pliocene/Pleistocene shelly unit.  Even if found in situ within the Plio/Pleistocene unit, such specimens could be reworked out of the Peace River Formation.  If you are finding them in modern creek alluvium, it will be difficult to be sure which is their original depositional unit.