page_title: Asterotrygon
section_title: History
hierarchical_section_title: Asterotrygon / History
caption_attribution_description: English: Fossile Butte National Monument, Wyoming, USA. View of the eponym Fossil Butte in the vicinity of the Historic Quarry Trail. The trail leads to the site of a fossil quarry in the Green River formation.
context_page_description: 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. The type and only species, A. maloneyi, was named in 2004 on the basis of these fossils. Another stingray, Heliobatis, is also known from 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.
context_section_description: Before the description of Asterotrygon, Heliobatis was the only known stingray in the Green River Formation. American paleontologist Othniel Charles Marsh named Heliobatis radians in 1877, and Xiphotrygon acutidens and Palaeodasybatis discus were subsequently named from the formation in 1879 and 1947, respectively. These stingrays were later synonymized with Heliobatis.
  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. A second specimen called FMNH PF 15166 included a female and a fetus that was still in an embryo within the animal. The genus Asterotrygon was erected in 2004 along with the type species A. maloneyi, and FMNH PF 15166 was designated the holotype specimen. AMNH P 11557 and many other complete fossils were also referred to A. maloneyi. Hundreds of fossils of Heliobatis have been found, while Asterotrygon is represented by a few dozen specimens. Asterotrygon means "star stingray" from the Greek asteros ("star") and trygon ("stingray") after the star-like shape of the base of each denticle. The type species A. maloneyi was named after Thomas Maloney, who donated the paratype specimen AMNH P 11557 to the American Museum of Natural History.
  Although Asterotrygon is not the earliest stingray (they were present as early as the Early Cretaceous, it is one of the most well-preserved of the early forms. Most earlier stingrays are known only from small teeth, dermal denticles, or stingers, but not entire bodies.
caption: Fossils of Asterotrtygon were found in Fossil Butte, Wyoming.
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