Borhyaenidae is an extinct

metatheria Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as w ...

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of low-slung, heavily built predatory mammals in the order

Sparassodonta Sparassodonta (from Greek to tear, rend; and , gen. , ' tooth) is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now t ...

. Borhyaenids are not true

marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in ...

s, but members of a sister taxon, Sparassodonta. Like most metatherians, borhyaenids and other sparassodonts are thought to have had a pouch to carry their offspring around. Borhyaenids had strong and powerful jaws, like those of the unrelated

placentalia Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...

ns '' Hyaenodon'' and ''

Andrewsarchus ''Andrewsarchus'' () is an extinct genus of mammal that lived during the middle Eocene epoch in what is now Inner Mongolia, China. Only one species is usually recognized, ''A. mongoliensis'', known from a single skull of great size discovered ...

'', for crushing bones. Borhyaenids grew up to an average of long. '' Borhyaena'' is the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

of this group. Originally, the borhyaenids were one of the most diverse groups of sparassodonts, including all species not originally included in the

Thylacosmilidae Thylacosmilidae is an extinct family of metatherian predators, related to the modern marsupials, which lived in South America between the Miocene and Pliocene epochs. Like other South American mammalian predators that lived prior to the Grea ...

. However, in recent years, with the elevation of most sparassodont subfamilies to family rank and the discovery that borhyaenids are more closely related to proborhyaenids and

thylacosmilid Thylacosmilidae is an extinct family of metatherian predators, related to the modern marsupials, which lived in South America between the Miocene and Pliocene epochs. Like other South American mammalian predators that lived prior to the Great A ...

s than other sparassodonts, the family has been reduced to seven species in four genera. The best studied borhyaenids are the Early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

taxa, particularly from fossil sites in the southernmost part of

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...

. One species, ''Australohyaena antiqua'', is known from the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

(

Deseadan The Deseadan ( es, Deseadense) age is a period of geologic time (29.0–21.0 Ma) within the Oligocene epoch of the Paleogene to the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It fol ...

); although some Oligocene basal borhyaenoids were once considered to be borhyaenids, all other unambiguous members of the group are now considered to be restricted to the

. The fossil record of this group after the Early Miocene is rather poor, and only fragmentary remains attest to their presence in the Late

. However, the only confidently identified Late

borhyaenid specimen comes from a site which is known to have Early Miocene fossils mixed in with Late Miocene ones, and so it may be that this group did not survive the end of the Early Miocene.

Classification

* †Family Borhyaenidae ** †Genus '' Arctodictis'' *** †''Arctodictis munizi'' *** †''Arctodictis sinclairi'' ** †Genus '' Acrocyon'' *** †'' Acrocyon riggsi'' *** †''Acrocyon sectorius'' ** †Genus '' Australohyaena'' *** †''Australohyaena antiqua'' ** †Genus '' Borhyaena'' *** †''Borhyaena tuberata'' *** †''Borhyaena macrodonta'' ** †Genus ?'' Eutemnodus''

References

Borhyaenidae - Encyclopædia Britannica
Sparassodonts Eocene first appearances Miocene extinctions Prehistoric mammal families {{paleo-mammal-stub