Heleosuchus
Encyclopedia
Heleosuchus is an extinct genus
of diapsid reptile from the Late Permian of South Africa
. It was originally described as a species of Saurosternon, but was later recognized as a separate taxon by Robert Broom.
At one time, the type specimen of Heleosuchus, was thought to be lost. However, it remains at the Natural History Museum
(formerly British Museum (Natural History)), where it is numbered 2374, and a cast R. 5000. Several other casts of Natural History Museum specimen 2374 are present in several other European institutions, among them a cast of higher fidelity to the original, the whereabouts of which are unknown.
While the type was thought to be lost, S. E. Evans redescribed this taxon on the basis of an older mold which had been taken of the type specimen prior to its disappearance. When the specimen appeared in later years, a higher quality mold was taken and described by R. L. Carroll that allowed a better description of this taxon.
Heleosuchus is only known from the posterior half of the skull and a cervicodorsal column with some associated forearm elements and hind limb elements. The hind limbs are better preserved than the forearms.
Heleosuchus is suggested as being either an early diapsid reptile, not closely related to other lineages, or as being an aberrant and primitive lepidosauromorph. Heleosuchus shares the hooked fifth metatarsal found in some other diapsids, such as primitive turtles (Odontochelys
), lepidosauromorphs, and archosauromorphs, but it also resembles "younginiform"-grade diapsids in its gross morphology. Heleosuchus may also share a thyroid fenestra with these higher diapsid reptiles as well, but the identity of this feature is disputed.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of diapsid reptile from the Late Permian of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. It was originally described as a species of Saurosternon, but was later recognized as a separate taxon by Robert Broom.
At one time, the type specimen of Heleosuchus, was thought to be lost. However, it remains at the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
(formerly British Museum (Natural History)), where it is numbered 2374, and a cast R. 5000. Several other casts of Natural History Museum specimen 2374 are present in several other European institutions, among them a cast of higher fidelity to the original, the whereabouts of which are unknown.
While the type was thought to be lost, S. E. Evans redescribed this taxon on the basis of an older mold which had been taken of the type specimen prior to its disappearance. When the specimen appeared in later years, a higher quality mold was taken and described by R. L. Carroll that allowed a better description of this taxon.
Heleosuchus is only known from the posterior half of the skull and a cervicodorsal column with some associated forearm elements and hind limb elements. The hind limbs are better preserved than the forearms.
Heleosuchus is suggested as being either an early diapsid reptile, not closely related to other lineages, or as being an aberrant and primitive lepidosauromorph. Heleosuchus shares the hooked fifth metatarsal found in some other diapsids, such as primitive turtles (Odontochelys
Odontochelys
Odontochelys semitestacea is an extinct turtle species, the oldest known one. It is the only known species in the genus Odontochelys and the family Odontochelyidae. O. semitestacea was first described from three 220 million year-old specimens excavated in Triassic deposits in Guizhou,...
), lepidosauromorphs, and archosauromorphs, but it also resembles "younginiform"-grade diapsids in its gross morphology. Heleosuchus may also share a thyroid fenestra with these higher diapsid reptiles as well, but the identity of this feature is disputed.
See also
- HeleosaurusHeleosaurusHeleosaurus is an extinct genus of non-mammalian synapsid from the Late Permian of South Africa. It was originally described as a diapsid reptile.-References:...
- Both Heleosaurus and Heleosuchus were at one time thought to be diapsid reptiles. - YounginaYounginaYoungina is an extinct genus of diapsid reptile from the Late Permian Beaufort Group of the Karoo Red Beds of South Africa. This, and a few related forms, make up the family Younginidae, within the Order Eosuchia...
- Heleosuchus was once suggested as being a relative of Youngina, but this view has been summarily dismissed in subsequent literature (Carroll, 1987; Evans, 1984).