Arctic Ice Age hyenas discovery

This 17 January 2019 video says about itself:

Chasmaporthetes, also known as hunting or running hyena, is an extinct genus of hyenas distributed in Eurasia, North America, and Africa. It lived during the Pliocene-Pleistocene epochs, from 4.9 million to 780,000 years ago, existing for about 4.12 million years.

The genus probably arose from Eurasian Miocene hyenas such as Thalassictis or Lycyaena, with C. borissiaki being the oldest known representative. It was a fast runner and an important carnivore on 4 continents during the Pliocene.

At least nine species are currently recognised. The genus type species is Chasmaporthetes ossifragus. It was assigned to Hyaenidae by Hay (1921), Geraads (1997), and Flynn (1998).

The species C. ossifragus was the only hyena to cross the Bering land bridge into the Americas. C. ossifragus 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.

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.

The genus has entered the popular culture lexicon as a result of cryptozoologic claims, having been proposed as the likely origin of the American Shunka Warakin and the Cuitlamiztli.

Chasmaporthetes was named by Hay (1921), who noted the name to be a reference to the possibility that the beginning of the Grand Canyon was witnessed by the North American species, C. ossifragus.

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.

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).

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, and competed with the far more numerous Borophagus diversidens.

A study on the genus’ premolar intercuspid notches indicated Chasmaporthetes was likely hypercarnivorous rather than durophagous as its modern cousins (excluding the aardwolf) are.

Like most of the animals of the time, reasons for its extinction are not known.

By Nicoletta Lanese, 6:00am, June 18, 2019:

Hyenas roamed the Arctic during the last ice age

Newly identified fossils confirm how the carnivores migrated to North America, researchers say

Modern hyenas stalk the savannas of Asia and Africa, but the animals’ ancient relatives may have had snowier stomping grounds: the Arctic. Two fossilized teeth, collected in Canada in the 1970s, confirm a long-held hunch that ancient hyenas ventured into North America via the Bering land bridge, scientists say.

The teeth belonged to members of the extinct genus Chasmaporthetes, also known as the “running hyena” for their unusually long legs, researchers report June 18 in Open Quaternary. Like wolves, the creatures could sprint over long distances. That ability that may have enabled the hyenas to make the long trek to America from Asia. Running hyena remains crop up across the southern United States and central Mexico. But before the Arctic discovery, a more than 10,000-kilometer gap lay between them and their closest relatives in Mongolia.

“This new Arctic find puts a dot right in the middle of that”, says paleontologist Jack Tseng of the University at Buffalo in New York. “It actually confirms previous hypotheses about how hyenas got to the New World.”

The teeth date to between 850,000 and 1.4 million years ago, Tseng says, placing the hyenas in the Arctic during the Pleistocene Ice Age, which began roughly 2.6 million years ago and lasted until about 11,700 years ago. The large carnivores may have hunted ancient caribou, horses, camels and the occasional juvenile mammoth (SN: 4/6/13, p. 9).

Paleontologists originally dug up the teeth in the Old Crow Basin in the Yukon at a site nicknamed the “supermarket of fossils”. There, rushing water dislodges fossils from their soil beds and drops them along bends in the river. The spoils can be reached only by boat or helicopter, but it’s worth the effort — over 50,000 known mammal fossils have been collected in the basin to date.

For decades, the hyena teeth lay buried among fossil specimens in the Canadian Museum of Nature in Ottawa. Few field notes referenced the finds, and an unpublished manuscript by archaeologist Brenda Beebe provided the only photographs. Tseng and his colleagues finally tracked the fossils down; they were a mere six-hour drive from his home base in Buffalo.

“Hyena are one of the groups with a really patchy fossil record in North America. This finding adds to our knowledge of how the species came over,” says paleontologist Julie Meachen of Des Moines University in Iowa, who was not involved in the study. The finding opens the door for further research on the migration of carnivores across the Bering land bridge (SN: 1/31/09, p. 5), Meachen says, and may help clarify which species competed for the same kills during the Pleistocene.

See also here.