Hyaenodon Middle | |
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Mounted H. sp. skeleton, Science Museum of Minnesota | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | † Hyaenodonta |
Superfamily: | † Hyaenodontoidea |
Family: | † Hyaenodontidae |
Subfamily: | † Hyaenodontinae |
Tribe: | † Hyaenodontini Leidy, 1869 [1] |
Genus: | † Hyaenodon Laizer & Parieu, 1838 |
Type species | |
†Hyaenodon leptorhynchus Laizer and Parieu, 1838 | |
Species | |
[see classification] | |
Synonyms [2] | |
synonyms of genus: synonyms of species:
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Hyaenodon ("hyena-tooth") is an extinct genus of carnivorous placental mammals from extinct tribe Hyaenodontini within extinct subfamily Hyaenodontinae (in extinct family Hyaenodontidae), [19] that lived in Eurasia and North America from the middle Eocene, throughout the Oligocene, to the early Miocene.
Typical of early carnivorous mammals, individuals of Hyaenodon had a very massive skull, but a small brain. The skull is long with a narrow snout—much larger in relation to the length of the skull than in canine carnivores, for instance. The neck was shorter than the skull, while the body was long and robust and terminated in a long tail. Compared to the larger (but not closely related) Hyainailouros , the dentition of Hyaenodon was geared more towards shearing meat and less towards bone crushing. [20]
Some species of this genus were among the largest terrestrial carnivorous mammals of their time; others were only of the size of a marten. Remains of many species are known from North America, Europe, and Asia. [21] The average weight of adult or subadult H. horridus, the largest North American species, is estimated to about 40 kg (88 lb) and may not have exceeded 60 kg (130 lb). H. gigas, the largest Hyaenodon species, was much larger, being 378 kg (833 lb) and around 10 ft (3 m). [20] H. crucians from the early Oligocene of North America is estimated to only 10 to 25 kg (22 to 55 lb). H. microdon and H. mustelinus from the late Eocene of North America were even smaller and weighed probably about 5 kg (11 lb). [22]
Studies on juvenile Hyaenodon specimens show that the animal had a very unusual system of tooth replacement. Juveniles took about 3–4 years to complete the final stage of eruption, implying a long adolescent phase. In North American forms, the first upper premolar erupts before the first upper molar, while European forms show an earlier eruption of the first upper molar. [23]
The various species of Hyaenodon competed with each other and with other hyaenodont genera (including Sinopa , Dissopsalis and Hyainailurus ), and played important roles as predators in ecological communities as late as the Miocene in Asia and preyed on a variety of prey species such as primitive horses like Mesohippus , Brontotheres, early camels, oreodonts and even primitive rhinos. [20] Species of Hyaenodon have been shown to have successfully preyed on other large carnivores of their time, including a nimravid ("false sabertooth cat"), according to analysis of tooth puncture marks on a fossil Dinictis skull found in North Dakota. [24] [25] Zigzag Hunter–Schreger bands in the enamel indicate that bone was a significant component of the diet of Hyaenodon. [26]
In North America the last Hyaenodon, in the form of H. brevirostrus, disappeared in the late Oligocene. [27] In Europe, they had already vanished earlier in the Oligocene. [21]
Creodonta is a former order of extinct carnivorous placental mammals that lived from the early Paleocene to the late Miocene epochs in North America, Europe, Asia and Africa. Originally thought to be a single group of animals ancestral to the modern Carnivora, this order is now usually considered a polyphyletic assemblage of two different groups, the oxyaenids and the hyaenodontids, not a natural group. Oxyaenids are first known from the Palaeocene of North America, while hyaenodonts hail from the Palaeocene of Africa.
Hyaenodontidae is a family of placental mammals in the extinct superfamily Hyaenodontoidea. Hyaenodontids arose during the early Eocene and persisted well into the early Miocene. Fossils of this group have been found in Asia, North America and Europe.
Paramiacis is an extinct genus of placental mammals from clade Carnivoraformes, that lived in Europe from the middle to late Eocene. Species P. exilis and P. teilhardi were long believed to be the same species, with differences that were only represented as an example of sexual dimorphism.
Asiavorator is an extinct genus of civet-like carnivoran belonging in the family Stenoplesictidae. It was endemic to Asia and lived during the Eocene and Oligocene epochs.
Palaeogale is an extinct genus of carnivorous mammal known from the Late Eocene, Oligocene, and Early Miocene of North America, Europe, and Eastern Asia. A small carnivore often associated with the mustelids, Palaeogale might have been similar to living genets, civets, and linsangs.
Pterodon is an extinct genus of hyaenodont in the family Hyainailouridae, containing five species. The type species Pterodon dasyuroides is known exclusively from the late Eocene to the earliest Oligocene of western Europe. The genus was first erected by the French zoologist Henri Marie Ducrotay de Blainville in 1839, who said that Georges Cuvier presented one of its fossils to a conference in 1828 but died before he could make a formal description of it. It was the second hyaenodont genus with taxonomic validity after Hyaenodon, but this resulted in taxonomic confusion over the validities of the two genera by other taxonomists. Although the taxonomic status of Pterodon was revised during the late 19th and early 20th centuries, it became a wastebasket taxon for other hyaenodont species found in Africa and Asia. Today, only the type species is recognized as belonging to the genus while four others are pending reassessment to other genera.
Cynohyaenodon is an extinct paraphyletic genus of placental mammals from extinct family Hyaenodontidae that lived from the early to middle Eocene in Europe.
Hyainailouros ("hyena-cat") is an extinct polyphyletic genus of hyaenodont belonging to the family Hyainailouridae that lived during the early to middle Miocene, of which there were at least three species spread across Europe, Africa, and Asia.
Apterodon is an extinct genus of hyaenodontid mammals that lived from the late Eocene through the middle Oligocene epoch in Africa and Europe. It is closely related to the African Quasiapterodon, and together it, they comprise the hyainailurids subfamily Apterodontinae.
Galecyon ("polecat-dog") is an extinct genus of placental mammals from extinct order Hyaenodonta, that lived in Europe and North America during the early Eocene.
Pyrocyon is an extinct genus of small carnivorous placental mammals from extinct order Hyaenodonta, that lived in North America during the early Eocene. Fossils of Pyrocyon have been found in Wyoming and Colorado. Weight of Pyrocyon dioctetus has been estimated at around 2.6 kilograms.
Hyaenodonta is an extinct order of hypercarnivorous placental mammals of clade Pan-Carnivora from mirorder Ferae. Hyaenodonts were important mammalian predators that arose during the early Paleocene in Europe and persisted well into the late Miocene.
Tytthaena is an extinct genus of placental mammals from extinct subfamily Tytthaeninae within extinct family Oxyaenidae, that lived in North America from the late Paleocene to early Eocene.
Isohyaenodon is an extinct polyphyletic genus of hyainailourid hyaenodont mammal from the subfamily Hyainailourinae). Remains are known from early to middle Miocene deposits in Kenya, East Africa.
Exiguodon is an extinct genus of hyainailourid hyaenodont mammal of the subfamily Hyainailourinae. Remains are known from early Miocene deposits in Kenya and Uganda, in East Africa.
Metapterodon is an extinct genus of hyainailourid hyaenodonts of the subfamily Hyainailourinae, that lived in Africa during the early Oligocene to early Miocene. Fossils of Metapterodon were recovered from the Egypt, Uganda, Elisabeth Bay Formation in Namibia, and Rusinga Island and Karungu in Kenya.
Limnocyoninae is a subfamily of extinct predatory mammals from extinct order Hyaenodonta. Fossil remains of these mammals are known from late Paleocene to late Eocene deposits in North America and Asia. Limnocyonines had only two molars in the upper and lower dentition.
Hyaenodontinae is an extinct subfamily of predatory placental mammals from extinct family Hyaenodontidae. Fossil remains of these mammals are known from early Eocene to early Miocene deposits in Europe, Asia and North America.
Hyainailourinae ("hyena-cats") is an extinct subfamily of hyainailourid hyaenodonts that lived in Africa, Asia, North America and Europe from the middle Eocene to middle Miocene. They appeared in Africa about 47.8 Ma ago and soon after spread as far as East Asia.
The Ergilin Dzo Formation, is a geologic formation in southeastern Mongolia. It preserves fossils of a wide variety of animals, which date back to the late Eocene epoch. The type fauna of the Ergilian Asian land mammal age is defined by the mammalian fossils of this formation.