Ischigualastia

Ischigualastia was briefly named by C. Barry Cox in 1962, with a larger description published in 1965. It is one of the better-known South American dicynodonts in terms of its variety of fossils, including several nearly complete skulls. Cox named the genus after its location of discovery, the Ischigualasto Valley, while the species honors James Jensen, who prepared some of its fossils. == Description ==

Ischigualastia is a member of the family Stahleckeriidae, a clade which includes some of the biggest dicynodonts. which measured around long and weighed up to . Indeed, Lucas Fiorelli and colleagues estimated in 2013 that the holotype specimen of Ischigualastia would have weighed around . Skull Ischigualastia is a very large dicynodont. The skull had a maximum known length of , In many respects, Ischigualastia is similar to a nearby relative, Jachaleria, though there are a few traits entirely unique to the skull of Ischigualastia. The top of the snout has a narrow depression, known as the interfrontal fossa, near where the frontal bones contact the nasal bones; the presence of this structure is unique among kannemeyeriiforms, though may be connected to an additional bone between the nasals in Jachaleria. The pineal foramen, a hole further back on the forehead, has swollen rims. Finally, the zygomatic arch (roughly equivalent to the cheekbone) is deep and strongly bent upwards. Robust Ischigualastia skulls, interpreted as males, have a distinctly broader snout and intertemporal area, as well as rugose (rough) patches on the nasal bones. == Classification ==

In 1965, C. Barry Cox suggested that Ischigualastia belonged to the family Kannemeyeriidae. In particular, it is generally considered part of the subfamily Stahleckeriinae, most closely related to Jachaleria. Below is a cladogram from Kammerer and Ordoñez (2021): Below is a cladogram from Szczygielski and Sulej (2023): == Paleoecology ==

Ischigualastia was a large quadrupedal herbivore found in late Carnian-age strata of the Ischigualasto Formation (La Peña, Cancha de Bochas, and earliest Valle de la Luna members). It was a relatively common component of the local fauna, although not as abundant as the medium-sized herbivores Hyperodapedon and Exaeretodon. It was one of the two dicynodonts which lived in the Ischigualasto Formation, the other being Jachaleria, a close relative which is only found in the youngest layers of the formation. The largest carnivores in the formation were the pseudosuchian Saurosuchus and the common predatory dinosaur Herrerasaurus. == See also ==