Proborhyaeninae

Proborhyaeninae is an extinct subfamily of the order Sparassodonta, a group of South American metatherian predators that lived during the Oligocene and Miocene epochs. Members of this subfamily were among the largest and most formidable of the borhyaenids, often referred to as "false saber-toothed cats" due to their superficially similar predatory adaptations. Proborhyaenines are distinguished by their robust build, powerful jaws, and specialized dentition.

The most characteristic feature of Proborhyaeninae is the presence of greatly enlarged, saber-like upper canines, though these were generally shorter and thicker than those of true saber-toothed cats like Smilodon. Their molars were adapted for shearing meat and crushing bone, indicating a diet that likely included large prey and possibly scavenging. The skull was massive, with a pronounced sagittal crest for the attachment of powerful jaw muscles. Their limbs were stocky and strong, suggesting an ambush predator or a persistent hunter capable of bringing down substantial animals.

Fossil evidence for Proborhyaeninae has been recovered from various South American countries, primarily Argentina and Uruguay. Notable genera within this subfamily include Proborhyaena and Arctodictis. These animals occupied a significant niche in their respective ecosystems, acting as apex predators and influencing the evolution of other South American fauna during the Cenozoic. Their extinction is thought to be linked to environmental changes and increased competition following the formation of the Isthmus of Panama, which allowed placental mammals to migrate into South America.