Rubidgeinae

Rubidgeinae is an extinct subfamily of gorgonopsid therapsids known only from Africa. They were among the largest gorgonopsians, and their fossils are common in the Cistecephalus and Daptocephalus assemblage zones of the Karoo Basin. They lived during the Late Permian, and became extinct at the end of the Permian.^[1]

Rubidgeinae Temporal range: Late Permian PreꞒ Ꞓ O S D C P T J K Pg N
Visualized head of Rubidgea atrox
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Clade:	†Gorgonopsia
Family:	†Gorgonopsidae
Subfamily:	†Rubidgeinae Broom, 1938
Genera
†Aelurognathus †Sycosaurus †Ruhuhucerberus †Rubidgeini †Clelandina †Dinogorgon †Leontosaurus †Rubidgea

Description

Rubidgeines were large, quadrupedal carnivores of the family Gorgonopsidae. Their largest teeth are their upper canines, which were blade-like and had well-developed serrations. Their postcanine teeth were small and conical, but were also frequently serrated. Tooth replacement was rapid relative to basal therocephalians. Rubidgeines can be distinguished from other gorgonopsians by the absence of a blade-like parasphenoid bone and reduced or absent preparietal bone. The jugal bone, while narrow in most gorgonopsians, was often broadly expanded in rubidgeines.^[1] The largest rubidgeins were Dinogorgon and Rubidgea.^[2]

Paleobiology

Clelandina rubidgei

Rubidgeines were among the largest gorgonopsians known, and the largest known from Africa. They were also the largest predators in their environment. Their massive canines and serrated teeth indicate that they were adapted for macropredation.

The robust skull roof and supraorbital bosses of rubidgeines likely acted to protect the skull from the stress inflicted during prey capture, and similar morphology has been seen in many other macropredators in the fossil record, including theropod dinosaurs. The presence of this skull morphology is one of multiple adaptations seen in predators that utilize the skull, rather than the limbs, in prey capture.^[1]

Classification and systematics

Below is a cladogram by Kammerer in 2016.^[1]

Rubidgeinae	Smilesaurus ferox Aelurognathus tigriceps Ruhuhucerberus haughtoni Sycosaurus laticeps Sycosaurus nowaki Rubidgeini Leontosaurus vanderhosti Dinogorgon rubidgei Rubidgea atrox Clelandina rubidgei

References

1. Christian F., Kammerer (January 26, 2016). "Systematics of the Rubidgeinae (Therapsida: Gorgonopsia)". PeerJ. 4: e1608. doi:10.7717/peerj.1608. PMC 4730894. PMID 26823998.
2. Frank Zachos, Robert Asher (October 22, 2018). Mammalian Evolution, Diversity and Systematics. De Gruyter. p. 158. ISBN 9783110341553. Retrieved 2022-08-25.