Named By: Gaudry - 1886.
Synonyms: Callibrachion Datheosaurus, Palaeohatteria, Pantelosaurus.
Classification: Chordata, Synapsida, Pelycosauria, Sphenacodontia.
Species: H. baylei (type). Possibly also H. garnettensis, H. gaudryi, H. grandis, H. macrourus.
Size: Between 70 and 150 centimetres long depending upon the species. Smaller species such as H. garnettensis about 70 centimetres, while larger species like H. baylei about 140 centimetres long.
Known locations: England - Kenilworth Sandstone Formation. France. Germany - Döhlen Formation, Niederhäslich-Schweinsdorf Formation. Poland - Ludwikowice Formation. USA, Kansas - Stanton Formation.
Time period: Kasimovian of the Carboniferous through to the Sakmarian of the Permian.
Fossil representation: Several individuals.
Easily one of the more common pelycosaurs in Europe, Haptodus was also one of the earliest with the first species appearing in the late Carboniferous period. Earlier species that appeared in the Carboniferous such as H. garnettensis were smaller at about seventy centimetres in length and were probably insectivores. By the early Permian however, species such as H. baylei were growing twice as big and probably incorporated small vertebrates into their diets as well. However, in recent years there have been some doubts to the validity of some of the species, which might result in some re-naming in the future.
- Lower Permian Pelycosaurs from the English Midlands. - Palaeontology 17(3):541-552. - R. L. Paton - 1974.
- A New Haptodontine Sphenacodont (Reptilia: Pelycosauria) from the Upper Pennsylvanian of North America. - Journal of Paleontology 51(5):927-942. - P. Currie - 1977.