Hyaenodontidae
Encyclopedia
Hyaenodontidae is a family of the extinct order
Creodonta
, which contains several dozen genera
.
The Hyaenodontids were important mammal
ian predators that arose during the late Paleocene
and persisted well into the Miocene
. They were considerably more widespread and successful than the related oxyaenids
.
), they generally ranged in size from 30 to 140 cm at the shoulder. While Hyaenodon gigas, the largest Hyaenodon species was as much as 1.4 m high at the shoulder, 10 feet long and weighed about 500 kg, most were in the 5–15 kg range, equivalent to a mid-sized dog
. Fossil evidence of their skulls shows that they had a particularly acute sense of smell, while their teeth were adapted for shearing, rather than crushing.
Because of their size range, it is probable that different species hunted in different ways and allowed them to fill many different predatory niche
s. Smaller ones would hunt in packs during the night like wolves, and bigger, fiercer ones would hunt alone during the daylight, using their sheer size and their mighty jaws as their principal weapon. The carnassial
s in a hyaenodontid are the second upper and third lower molar
s.
to Africa
, and were important hypercarnivores in Eurasia, Africa and North America during the Oligocene, but, lost ground to the carnivoran mammals, with almost the entire family becoming extinct by the close of the Oligocene. Only four genera, Megistotherium
, and its sister genus, Hyainailouros, Dissopsalis
, and the youngest species of Hyaenodon, H. weilini, survived into the Miocene, of which, only Dissopsalis survived long enough to go extinct at the close of the Miocene.
The Machaeroidinae are sometimes placed here, e.g. by Egi, 2001.
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Creodonta
Creodonta
The creodonts are an extinct order of mammals that lived from the Paleocene to the Miocene epochs. They shared a common ancestor with the Carnivora....
, which contains several dozen genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
The Hyaenodontids were important mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian predators that arose during the late Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
and persisted well into the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
. They were considerably more widespread and successful than the related oxyaenids
Oxyaenidae
Oxyaenidae is a family of the extinct order Creodonta; it contains three subfamilies comprising ten genera. The placement of a fourth subfamily, Machaeroidinae, is unsure; it may belong here or in Hyaenodontidae....
.
General Characteristics
Characterized by long skulls, slender jaws, slim bodies, and a tendency to walk on their toes rather than flat-footed (plantigradePlantigrade
right|151px|thumb|Human skeleton, showing plantigrade habitIn terrestrial animals, plantigrade locomotion means walking with the podials and metatarsals flat on the ground. It is one of three forms of locomotion adopted by mammals...
), they generally ranged in size from 30 to 140 cm at the shoulder. While Hyaenodon gigas, the largest Hyaenodon species was as much as 1.4 m high at the shoulder, 10 feet long and weighed about 500 kg, most were in the 5–15 kg range, equivalent to a mid-sized dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
. Fossil evidence of their skulls shows that they had a particularly acute sense of smell, while their teeth were adapted for shearing, rather than crushing.
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
s. Smaller ones would hunt in packs during the night like wolves, and bigger, fiercer ones would hunt alone during the daylight, using their sheer size and their mighty jaws as their principal weapon. The carnassial
Carnassial
Carnassials are large teeth found in many carnivorous mammals, used for shearing flesh and bone in a scissor- or shear-like way. In the Carnivora, the carnassials are the modified last upper premolar and the first molar, but in the prehistoric creodonts, the carnassials were further back in the...
s in a hyaenodontid are the second upper and third lower molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
s.
Range
Hyaenodontids ranged from North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
to Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, and were important hypercarnivores in Eurasia, Africa and North America during the Oligocene, but, lost ground to the carnivoran mammals, with almost the entire family becoming extinct by the close of the Oligocene. Only four genera, Megistotherium
Megistotherium
Megistotherium is an extinct genus of creodonts, the only known species of which is Megistotherium osteothlastes....
, and its sister genus, Hyainailouros, Dissopsalis
Dissopsalis
Dissopsalis is a genus of extinct predatory mammals of the order Creodonta. The older species, D. pyroclasticus, lived in Kenya during the middle Miocene, while the type species, D. carnifex, ranged from, Pakistan, India to China during the middle to late Miocene .Dissopsalis is the last known...
, and the youngest species of Hyaenodon, H. weilini, survived into the Miocene, of which, only Dissopsalis survived long enough to go extinct at the close of the Miocene.
Genera
- ORDER CREODONTACreodontaThe creodonts are an extinct order of mammals that lived from the Paleocene to the Miocene epochs. They shared a common ancestor with the Carnivora....
creodonts- Suborder Preptotheria
- Family Hyaenodontidae
- Subfamily Hyaenodontinae
- Genus HyaenodonHyaenodonHyaenodon is an extinct genus of Hyaenodonts, a group of carnivorous creodonts of the family Hyaenodontidae endemic to all continents except South America, Australia and Antarctica, living from 42—15.9 mya, existing for approximately .-Morphology:Some species of this genus were amongst the largest...
(syn. Alloeodectes, Neohyaenodon, Pseudopterodon) - Genus Isohyaenodon
- Genus Metapterodon
- Genus Neoparapterodon
- Genus Pyrocyon
- Genus Hyaenodon
- Subfamily Hyainailourinae
- Genus Anasinopa
- Genus Apterodon (syn. Dasyurodon)
- Genus Buhakia
- Genus DissopsalisDissopsalisDissopsalis is a genus of extinct predatory mammals of the order Creodonta. The older species, D. pyroclasticus, lived in Kenya during the middle Miocene, while the type species, D. carnifex, ranged from, Pakistan, India to China during the middle to late Miocene .Dissopsalis is the last known...
- Genus Francotherium
- Genus Hyainailouros (syn. Sivapterodon),
- Genus MegistotheriumMegistotheriumMegistotherium is an extinct genus of creodonts, the only known species of which is Megistotherium osteothlastes....
- Genus Metasinopa
- Genus PterodonPterodon (mammal)Pterodon is an extinct genus of superficially wolf-like creodonts that lived during the late Eocene, 30 million years ago....
- Subfamily Limnocyoninae
- Genus Iridodon
- Genus Limnocyon (syn. Telmatocyon)
- Genus Oxyaenodon
- Genus Prolimnocyon
- Genus Thinocyon
- Subfamily Proviverrinae
- Genus Allopterodon
- Genus Arfia
- Genus Boualitomus
- Genus Cynohyaenodon
- Genus Eurotherium
- Genus Kyawdawia
- Genus Leonhardtina
- Genus Masrasector
- Genus Paracynohyaenodon
- Genus Paratritemnodon
- Genus Prodissopsalis
- Genus Prototomus
- Genus ProviverraProviverraProviverra is an extinct genus of creodonts that lived during the Eocene in United States and Europe....
(syn. Mimocyon) - Genus SinopaSinopaSinopa is an extinct genus of creodonts that lived during the Eocene to Early Oligocene in United States and Egypt.Sinopa was one of the smaller creodonts to the family Hyaenodontidae. His carnassials teeth was the second upper molar and the lower third. Sinopa had an estimated weight of 1.3 to 1.4...
(syn. Stypolophus, Triacodon) - Genus Tinerhodon
- Incertae sedisIncertae sedis, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
- Genus Acarictis
- Genus Ahknatenavus
- Genus Alienetherium
- Genus Consobrinus
- Genus Galecyon
- Genus Gazinocyon
- Genus Geiselotherium
- Genus Hemipsalodon
- Genus Hyaenodontipus
- Genus Imperatoria
- Genus Ischnognathus
- Genus Leakitherium
- Genus Orienspterodon
- Genus Oxyaenoides
- Genus Paenoxyaenoides
- Genus Parapterodon
- Genus Paravagula
- Genus Paroxyaena
- Genus Praecodens
- Genus Prolaena
- Genus Propterodon
- Genus Proviverroides
- Genus Quasiapterodon
- Genus Quercitherium
- Genus Schizophagus
- Genus Teratodon
- Genus Thereutherium
- Genus TritemnodonTritemnodonTritemnodon was a genus of creodont which lived 54-38 million years ago. Fossils of this animal have been found in Willwood Formation of Big Horn County and the Lower Bridger Formation of Uinta County, Wyoming. It was the size of a wolf.-References:...
- Genus Yarshea
- Subfamily Hyaenodontinae
- Family Hyaenodontidae
- Suborder Preptotheria
The Machaeroidinae are sometimes placed here, e.g. by Egi, 2001.