Rubidgea

The first Rubidgea fossil was discovered by C. J. M. "Croonie" Kitching, the father of renowned paleontologist James Kitching, on the farm Doornberg outside the small town Nieu-Bethesda during the early 1930s. In a paper published in 1938, Robert Broom named the fossil Rubidgea kitchingi. Broom noted the large size of the new gorgonopsid fossil, stating that it was a new species. Subsequent discoveries in the following decades confirmed Broom's suspicions that a new subfamily of gorgonopsians should be categorised, and the Rubidgeinae was erected. ==Description==

Rubidgea was the largest African gorgonopsian and one of the largest gorgonopsians known to have lived. The largest specimens had skulls that measure up to in length. It has been estimated at in length. Rubidgea was a heavily-built, large-bodied apex predator, and sported a thick skull with long, sabre-like canines. The Rubidgeinae group as a whole were some of the largest gorgonopsians known to have lived, only outsized by Inostrancevia, and are characterised by their robust skeletal features, particularly their skulls which are heavily-pachyostosed. The genus Rubidgea is composed of three species, R. atrox, R. platyrhina, and R. majora. ==Classification==

skull The Rubidgeinae are a subfamily of derived gorgonopsids that have only been found in Africa. They are composed of six genera and 17 species. The Rubidgeinae are closely related to their sister group, the Inostranceviinae, which have only been found in Russia. Out of the gorgonopsian clade, the systematics of the Rubidgeinae is the best resolved due to their distinctive character traits. The systematics of other gorgonopsian subfamilies remain chaotic due to a high degree of cranial homomorphism between taxa, making it difficult to distinguish different taxa effectively. The cladogram below (Kammerer and Rubidge 2022) displays the currently accepted systematic relationships of the Gorgonopsia. }} ==Correlation==

Numerous therapsid species, including rubidgenae gorgonopsids, are used as biostratigraphic markers in other African Basins, such as the Upper Madumabisa Mudstone Formation of Zambia, and the Chiweta Beds of Malawi. Rubidgea fossils have been recovered from the Usili Formation of Tanzania, indicating biostratigraphic correlation with upper Permian-aged deposits in South Africa. No rubidgeinae fossils have been found outside of African deposits to date, although the Inostranceviinae are considered to be their Russian counterparts. In 2023, fossils of Inostrancevia were described from South Africa, dating to the onset of the Permian–Triassic extinction event. The same paper found no evidence for the survival of Rubidgea to the P–Tr boundary and concluded the genus went extinct prior to it. In 2024, fossils of Inostrancevia were described from the Usili Formation, showing it coexisted with rubidgines before the onset of the end-Permian extinction. ==References==