Paleoart of Estemmenosuchus, a mid-Permian synapsid that had strange lumps on the face. It's been postulated that these were a form of sexual display, and thus Estemmenosuchus may have been dimorphic. As such, the female and juveniles lack the same protuberances. Unlike many mammals, it's likely many Permian synapsids had advanced color vision due to not experiencing the nocturnal bottleneck. As such, visual display via coloration may have been more common than it is in synapsids nowadays. Although commonly thought of as sweltering (not that it couldn't be), the Permian was situated during a great ice age. At its fullest extent, huge ice caps coated the southern hemisphere. The northern hemisphere wasn't quite as chilly, but it still got sea ice - and, almost certainly, synapsids of the north such as these Estemmenosuchus would have seen snow (and perhaps would be fond of playing in puddles of slush... Canvas textures courtesey of aopsan (freepik) and mongkol kornkamol (vecteezy), both free with attribution.
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