Asterotrygon is an extinct genus of stingray from the Eocene Green River Formation in Wyoming.

Several complete skeletons representing juveniles, adults, males and females have been uncovered from the late early Eocene Fossil Butte Member of the formation.

Asterotrygon is a primitive stingray closely related to the living family Urolophidae whose ancestors likely originated in the Indo-Pacific.

It lived in Fossil Lake, a body of water that existed in a subtropical mountainous region for only about 2 million years.

Asterotrygon had a typical stingray shape with a flat, rounded disk formed from the head and pectoral fins and a long, narrow tail with sharp stingers.

Unlike Heliobatis and modern stingrays, it has a small dorsal fin in front of its stingers.

[1] In 1980, a Green River fossil called AMNH P 11557 was described that included a female stingray and two smaller individuals thought to be aborted fetuses.

The genus Asterotrygon was erected in 2004 along with the type species A. maloneyi, and FMNH PF 15166 was designated the holotype specimen.

The type species A. maloneyi was named after Thomas and Hilda Maloney, who donated the paratype specimen AMNH P 11557 to the American Museum of Natural History.

[1] Asterotrygon and other organisms from the Green River Formation lived in subtropical lakes in a mountainous region.

The F-2 layer is thicker, up to 4 metres (13 ft), and was deposited over a longer period of time, possibly several thousand years.

F-2 limestone was deposited closer to the north and southeastern shorelines of the lake where the water was richer in dissolved oxygen and organic material.