Rubidgeinae from South Africa

Rubidgeinae is a subfamily of advanced gorgonopsians. In 2016, it was revised in detail by Christian Kammerer, and of 36 species already described, 9 were recognized as distinct and valid. Between them, 7 are remarkable together for a reason: they lived in the same place and time, in the Karoo Basin (South Africa) during the Late Permian. They are Smilesaurus ferox, Aelurognathus tigriceps, Sycosaurus laticeps, Leontosaurus vanderhorsti, Dinogorgon rubidgei, Rubidgea atrox and Clelandina rubidgei.

7 large predators (with skulls of no less than 30 cm, with some exceeding 40 cm) sharing an ecosystem imply some interesting factors, such their possible specializations to occupy different niches and decrease the competition, making the coexistence possible.

The dentition gives clues of these distinct adaptations, where the number and size of the teeth varies among species - for example, some have post-canine teeth and some do not (or have them reduced), which may indicate their preferences for prey of different size (it is speculated that rubidgeines without post-canine teeth, as Clelandina, preferred to hunt smaller animals that could be swallowed whole after being easily killed only with the incisors and canines). There are also variations among the characteristic canines, which would influence the way that each animal hunted. The proportionally larger canines are seen in Smilesaurus, which would have hunted more like the "saber-toothed" felines than like other gorgonopsids.

We also have a possible indicator that these animals were active through different periods of the day, since Clelandina has curiously small sclerotic rings (notice the small eyes), what shows a strictly diurnal animal. We do not know if this characteristic is shared by the other rubidgeines, as we do not have their sclerotic rings preserved, but it is quite probable that the activity in separated periods of the day would have facilitated the existence of these 7 species in the same environment.

Check also a full body rendition of the enormous Rubidgea: fav.me/dcmeqpn