Chasmaporthetes

Chasmaporthetes, also known as hunting or running hyena, is an extinct genus of hyenas^[1][2][3][4] distributed in Eurasia, North America, and Africa during the Pliocene-Pleistocene epochs, living from 4.9 million to 780,000 years ago, existing for about 4.12 million years.^[5] The genus probably arose from Eurasian Miocene hyenas such as Thalassictis or Lycyaena, with C. borissiaki being the oldest known representative.^[6] The species C. ossifragus was the only hyena to cross the Bering land bridge into the Americas, and ranged over what is now Arizona and Mexico during Blancan and early Irvingtonian Land Mammal ages, between 5.0 and 1.5 million years ago.^[6][4]

Chasmaporthetes Temporal range: Pliocene–Early Pleistocene PreꞒ Ꞓ O S D C P T J K Pg N ↓
C. progressus skull, National Natural History Museum of China
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Suborder:	Feliformia
Family:	Hyaenidae
Subfamily:	Hyaeninae
Genus:	†Chasmaporthetes Hay, 1921
Species
See text
Synonyms
Ailuriaena johnstoni Stirton & Christian, 1940 Euryboas

Chasmaporthetes was one of the so-called "dog-like" hyenas (of which the aardwolf is the only survivor), a hyaenid group which, in contrast to the now more common "bone-crushing" hyenas, evolved into slender-limbed, cursorial hunters like modern canids.^[4]

Taxonomy and etymology

Chasmaporthetes was named (from chasm and the Greek πορθευτής (portheutes), "destroyer, ravager") by Hay (1921), who noted that the name meant that the North American species, Chasmaporthetes ossifragus (the type species) possibly saw the beginning of the Grand Canyon.

Species

Fossil jaw of C. ossifragus, the only American species (FLMNH)

At least nine species are currently recognised:^[7][8]

• Chasmaporthetes ossifragus Hay, 1921 - North America, Pliocene to Pleistocene
• C. australis Hendey, 1974 - Africa, Late Miocene
• C. bonisi Koufos, 1987 - Greece, Late Miocene
• C. borissiaki Khomenko, 1932 - Russia, Pliocene (disputed^[9])
• C. exitelus Kurtén & Werdelin, 1988 - China, Late Miocene
• C. gangsriensis Tseng, Li, & Wang, 2013 - Asia, Early Pliocene^[7]
• C. lunensis Del Campana, 1914 - Eurasia, Late Miocene to Early Pleistocene
• C. melei Rook et al, 2004 - Sardinia, Early Pleistocene^[9]
• C. nitidula Geraads, 1997 - Africa, Pliocene to Early Pleistocene

Anatomy and paleoecology

C. lunensis skull

The limb bones of Chasmaporthetes were long and slender like those of cheetahs, and its cheek teeth were slender and sharp-edged like those of a cat. Chasmaporthetes likely inhabited open ground and was a daytime hunter.^[10] A study on the genus' premolar intercuspid notches indicated Chasmaporthetes was likely hypercarnivorous rather than durophagous as its modern cousins (excluding the aardwolf) are.^[11]

Dental microwear of C. australis from Langebaanweg in South Africa shows that the species was hypercarnivorous and rarely engaged in durophagy; its dental microwear was similar to the modern lion, which seldom consumes bone.^[12] In Europe, the species C. lunensis competed with the giant cheetah Acinonyx pardinensis, and may have preyed on the small Bourbon gazelle (Gazella borbonica) and the chamois antelope (Procamptoceras brivatense).^[10] The North American C. ossifragus was similar in build to C. lunensis, but had slightly more robust jaws and teeth. It may have preyed on the giant marmot Paenemarmota,^[6] and competed with the far more numerous Borophagus diversidens.^[13]