fossil

Fossilized Stingray Mouth Plate

Myliobatidae gen. et sp. indet. (e.g., Myliobatis, Aetobatus)

Hardness: 3.5-5 (apatite mineral structure). Color: Dark brown, black, to charcoal grey due to mineralization. Luster: Sub-vitreous to waxy. Structure: Parallel, intergrown chevron-like pavement tooth plates designed for crushing shells.

Hardness: 3
Color: Dark brown, black, to charcoal grey due to mineralization
Luster: Sub-vitreous to waxy

Identified July 26, 2026More fossil →

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Physical properties

Formation & geological history

Formed from the tooth plates of prehistoric eagle rays and stingrays (Family Myliobatidae). These rays had flattened, pavement-like tooth plates used to crush hard-shelled prey like mollusks and crabs. Over millions of years (typically Miocene to Pliocene epochs, 23 to 2.5 million years ago), bone and dentin tissue absorbed minerals from surrounding marine sediments, becoming permineralized.

Uses & applications

Highly sought after by fossil collectors and beachcombers. Used for educational displays, jewelry, and personal collections.

Geological facts

Stingrays do not have individual sharp teeth like sharks; instead, they possess flattened tooth plates made of stacked rows of modified dermal denticles that act like a conveyor belt to grind open prey. These plates frequently disarticulate and fossilize along ancient coastal waters.

Field identification & locations

Identify by looking for distinct parallel ridges or a honeycomb-like porous structure along the cross-section. Commonly found on beaches along the US Atlantic coast, such as Venice Beach, Florida, and Calvert Cliffs, Maryland.

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