Erpetonyx is an extinct genus of bolosaurian parareptile from the Gzhelian stage of the Carboniferous period, with a single known species: Erpetonyx arsenaultorum. It is known from a single articulated and mostly complete specimen from Prince Edward Island in Canada. Phylogenetics has predicted that parareptiles first evolved in the Carboniferous, parallel to eureptiles ("true reptiles"). However, Hylonomus, the oldest eureptile known from fossil evidence, lived millions of years before parareptiles appeared in the fossil record. The discovery of Erpetonyx helped to shorten this gap between pa
Erpetonyx is an extinct genus of bolosaurian parareptile from the Gzhelian stage of the Carboniferous period, with a single known species: Erpetonyx arsenaultorum. It is known from a single articulated and mostly complete specimen from Prince Edward Island in Canada. Phylogenetics has predicted that parareptiles first evolved in the Carboniferous, parallel to eureptiles ("true reptiles"). However, Hylonomus, the oldest eureptile known from fossil evidence, lived millions of years before parareptiles appeared in the fossil record. The discovery of Erpetonyx helped to shorten this gap between parareptile and eureptile fossils, as Erpetonyx lived in the Late Carboniferous and is one of the oldest known parareptiles (though Carbonodraco is now known to be older). However, it was not closely related to ancestral parareptiles, so its discovery also indicated that the initial diversification of parareptiles occurred earlier in the Carboniferous. Erpetonyx was a small reptile, with the entire skeleton about 20 to 25 centimeters (7.9 to 9.8 inches) in length. It was likely carnivorous, and could be characterized by a variety of skeletal features, including a relatively elongated body and large claws with powerful tendon attachment points.
== Discovery == Erpetonyx is known from a single specimen, a remarkably well-preserved skeleton, designated ROM 55402. This specimen hailed from Cape Egmont, in southwestern Prince Edward Island, Canada, in rock layers of the Edgmont Bay Formation that preserves fossils that date back to Gzhelian stage of the Carboniferous period. The specimen was discovered by nine-year-old Michael Arsenault in 2003 who was on vacation with his family at the time. It was acquired by the Royal Ontario Museum (ROM) in 2004, and later rep. Cape Breton University's Sean Modesto, a paleontologist and expert in ancient reptiles, was the lead author of a 2015 article published in the Proceedings of the Royal Society, The team, which included researchers from the ROM, University of Toronto and the Smithsonian Institution, described and named the new genus and species, the first parareptile known from Carboniferous period fossils.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).