Borhyaena

Borhyaena was a genus part of the order Sparassodonta, an extinct order of metatherian predators. It is the type genus of the family Borhyaenidae, part of the superfamily Borhyaenoidea. This superfamily includes other families such as Proborhyaenidae and Thylacosmilidae. ==Description==

Borhyaena was a predator and had a large head and a long, powerful neck similar to living hyenas. Its legs were adapted to cursoriality, albeit less specialized than those of wolves or the thylacine. The most complete specimen is estimated to have weighted and stood at the shoulders. One study suggested that Borhyaena may have been even larger, weighing . although this has been questioned by some experts. The tail of Borhyaena is believed to have been lighter and less muscled than Prothylacinus. == Paleobiology ==

Predatory behavior While having some adaptations of cursoriality, Borhyaena wasn’t a true cursorial predator due to the generalized morphology of the autopodials, femur, and tibia, instead it may have been a long distance traveler, not a fast runner. Compared to modern day pursuit predators, its legs were shorter and heavier. The dentition of Borhyaena suggests it wasn’t a specialist in Osteophagy. One expert suggested that the foraging behavior of the animal is believed to have been comparable to the striped hyena, searching for smaller foods in denser vegetation without cooperation from individuals. However, other experts suggested Borhyaena was capable of hunting larger animals. Compared to early sparassodonts, later diverging sparassodonts such as Borhyaena and Thylacosmilus had lower hearing ranges of frequency compared to other metatherians in the study. == Paleoecology ==

garretorum and Borhyaena tuberataThe genus has been found in Patagonia, Argentina (Santa Cruz and Sarmiento Formations) and Chile (Río Frias Formation). Santa Cruz Formation had a heterogeneous environment with patches forests, semi-arid forests, and open areas. Within this formation, B. tuberata coexisted with other sparassodonts. This included fellow borhyaenoids such as Acrocyon sectorius, Artodictis munizi, Lycopsis torresi, and Prothylacynus patagonicus. Hathliacynids were also present including Acyon tricuspidatus, Cladosictis patagoncia, Pseudonotictis pusillus, Perathereutes pungens, and Sipalocyon. Because of its large size, it would’ve been capable of displacing Acrocyon and Cladosictis. Borhyaena also coexisted with birds such as Brontornis, the cariamid Cariama santacrucensis, and phorusrhacids such as Patagornis marshi, Phorusrhacos, and Psilopterus bachmanni. Terror birds and sparassodonts likely occupied different niches due to locomotive differences. Herbivores present in Santa Cruz Formation included litoperns such as Diadiaphorus, Theosodon, and Tetramerorhinus, sloths such as Eucholoeops and Hapalops, and the toxodontid notoungulate Adinotherium. Borhyaena may have typically preyed on animals that weighed , such as Hapalops''. ==References==