| Named By: | S. P. Modesto, D. M. Scott, M. J. MacDougall, H. inD. Sues, D. C. Evans in R. R. Reisz in 2015 |
| Time Period: | Pennsylvanian, 303.7-289.9 Ma |
| Location: | Canada, Prince Edward Island |
| Size: | Roughly about 35-30 centimetres long |
| Diet: | Insectivore |
| Fossil(s): | Almost complete individual |
| Classification: | | Chordata | Reptilia | Procolophonomorpha | |
Erpetonyx arsenaultorum is an extinct genus of bolosaurian parareptile from the uppermost or Gzhelian stage of the Carboniferous rocks. It is known from a single, articulated and mostly complete specimen from Cape Egmont, in southwestern Prince Edward Island, Canada Prince County, in the Edgmont Bay Formation that preserves fossils in the stratigraphic layer that dates back to the Carboniferous period. It is the earliest known parareptile, and brings back the origins of several clades into the Carboniferous.
It 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. Cape Breton University's Sean Modesto, a paleontologist and expert in ancient reptiles was lead author of in 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 species, the first Carboniferous geologic period parareptile to be described since c. 2003.
The name Parareptilia was identified by the American zoologist, Olson (1910-1993), in 1947 and Bolosauria was identified by Oskar Kuhn in 1959. Erpetonyx arsenaultorum was described and named by Modesto et al. in 2015. It is the closest relative of bolosaurids.