16.8" Rare Fat Tail Stingray (Asterotrygon) - Wyoming

This is a rare, fossil "fat tail" stingray (Asterotrygon maloneyi) from the Green River Formation in Wyoming. This is the rarer of the two species of stingrays found in the formation. This 16.8" specimen is gorgeously preserved and nicely centered on a 22 x 12.26" slab. Just check out the closeup photos to see the preserved detail.

There are several repaired cracks running through the rock and the fossil and some restoration along these crack repairs. Because the shale it was found on is quite thin the piece has been backed with wood for stability. It comes with a display stand, and we can install a wall hanger upon request at no charge.

Asterotrygon is an extinct genus of freshwater ray primarily known from the Green River Formation in Wyoming. The teeth are triangular and shaped for feeding on small fish, crustaceans, and mollusks.

The shape of the disk is rounder than those of other extinct stingrays such as Heliobatis, which are more diamond-shaped. The upper surface of the disk is covered in small dermal denticles, each with a small hook.

Unlike Heliobatis (the more common ray in the Green River Formation) and modern stingrays, it has a small dorsal fin in front of its stingers. While most stingrays have a cartilaginous rod extending from the stinger to the tip of the tail, Asterotrygon retains separate vertebrae throughout the tail's entire length. The tail is also somewhat thicker at its base than those of other stingrays. Small fin-like tail folds are present at the tip of the tail.
Asterotrygon maloneyi
Kemmerer, WY
Green River Formation
16.8" long on 22 x 12.6" rock
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