| Ekorus Temporal range: Late Miocene, | |
|---|---|
 | |
| Ekorus ekakeran | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Mustelidae |
| Genus: | † Ekorus Werdelin, 2003 |
| Species: | †E. ekakeran |
| Binomial name | |
| †Ekorus ekakeran Werdelin, 2003 | |
Ekorus ekakeran is a large, extinct mustelid mammal. Fossils, including largely complete skeletons, are known from the late Miocene of Kenya. [1]
Ekorus reached almost 44 kg (97 lb), comparably to a wolf [2] and much bigger than the modern honey badger ( Mellivora capensis ). [3] Standing 60 cm (2.0 ft) tall at the shoulders, its build was not similar to that of modern mustelids. Small, modern-day weasels have short legs and can only achieve short bursts of speed. Living large mustelids are either aquatic predators (the otters, Lutrinae), or terrestrial animals with a crouching stance and heavy limbs with adaptations for digging (the wolverine, and various groups called badgers). Ekorus is a representative of an extinct ecological type of mustelid – large stalking and running mammals comparable to dogs, cats, hyenas, and amphicyonids. The legs of Ekorus are built like those of leopards. [4] The face is short, with a felid-like tooth pattern; Ekorus was a hypercarnivore. Analysis of the elbow indicates that it was a strong runner, like modern hyenas and dogs, and did not grapple with its paws, as bears and raccoons do. The legs are long; the feet are short and stout. [5]
Fossils of giant Miocene mustelids with similar morphology, reconstructed as hypercarnivores or carnivore-scavengers, have also been discovered in North America, [6] Europe, [7] and Asia, [8] as well as other parts of Africa. [9]
Apparently before the African savannas evolved, the giant mustelid Ekorus stalked its prey, such as the three-toed horse Eurygnathohippus and the large pig Nyanzachoerus , in forests and woodlands.
In the early Cenozoic, Africa was isolated from Eurasia, where modern African groups such as cats and giraffes first evolved. African predators and prey developed along their own lines to hunt in closed environments. Ekorus had the upright stance typical of active hunters, lacked digging adaptations, and was leopard-sized, with leopard-like body proportions. Since leopards are ambush hunters in forests and woodlands, [10] Ekorus may have filled a parallel role in the Miocene forests of Africa. [11] Other research has suggested the genus was cursorial, chasing down prey more like a modern wolf or spotted hyena. [5] In general, Miocene predators show larger body sizes with anatomies between the modern "dog-like" pursuit running and "cat-like" stalk-pounce-and-grapple strategies. This was suggested to be the result of the great abundance of prey species in Miocene forests, which allowed predators to survive without having to specialize as either fast runners or grapplers. [12]
Felids are first recorded on the continent in the early Miocene, in north Africa. [13] Tectonic changes starting about 35 million years ago led to the formation of the Great Rift Valley, and the rise of highlands that cause rain shadows in the surrounding region. Before the rift opened, Kenya was more forested. [14] Grasslands began to spread across Africa in the mid-Miocene, slowly replacing closed forest environments with open savannas. [15] Any or all of these factors may have led to the replacement of Ekorus and other large mustelid hunters by modern felids, hyaenids, and canids.
Carnivora is an order of placental mammals that have specialized in primarily eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the fifth largest order of mammals, comprising at least 279 species.
The Mustelidae are a diverse family of carnivorous mammals, including weasels, badgers, otters, martens, and wolverines. Otherwise known as mustelids, they form the largest family in the suborder Caniformia of the order Carnivora with about 66 to 70 species in nine subfamilies.
Amphicyonidae is an extinct family of terrestrial carnivorans belonging to the suborder Caniformia. They first appeared in North America in the middle Eocene, spread to Europe by the late Eocene, and further spread to Asia and Africa by the early Miocene. They had largely disappeared worldwide by the late Miocene, with the latest recorded species at the end of the Miocene in Africa. They were among the first carnivorans to evolve large body size. Amphicyonids are colloquially referred to as "bear-dogs".
Mellivora is a genus of mustelids that contains the honey badger or ratel (Mellivora capensis). It is also the sole living representative of the subfamily Mellivorinae. Additionally, two extinct species are known. The honey badger is native to much of Africa and South Asia, while fossil relatives occurred in those areas and Southern Europe.
Chasmaporthetes, also known as hunting or running hyena, is an extinct genus of hyenas 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. The genus probably arose from Eurasian Miocene hyenas such as Thalassictis or Lycyaena, with C. borissiaki being the oldest known representative. 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.
Amphicyon is an extinct genus of large carnivorans belonging to the family Amphicyonidae, subfamily Amphicyoninae, from the Miocene epoch. Members of this family received their vernacular name for possessing bear-like and dog-like features. They ranged over North America, Europe, Asia, and Africa.
Guloninae is a subfamily of the mammal family Mustelidae distributed across Eurasia and the Americas. It includes martens and the fisher, tayra and wolverine. These genera were formerly included within a paraphyletic definition of the mustelid subfamily Mustelinae.
Megalictis is an extinct genus of large predatory mustelids that existed in North America during the "cat gap" from the Late Arikareean (Ar4) in the Miocene epoch. It is thought to have resembled a huge, jaguar-sized ferret, weighing up to 60–100 kilograms (130–220 lb).
Agnotherium is a genus of large sized carnivoran mammals, belonging to the Amphicyonidae, which has been found in Western Europe, and possibly China and Northern Africa, and lived during the Late Miocene epoch. Despite only being known from fragmentary remains, the genus notable for hypercarnivorous adaptions, which have been said to represent the "apex" among its family.
Ysengrinia is an extinct genus of carnivoran in the family Amphicyonidae (beardogs), which lived in Europe, Asia, and North America during the Early Miocene. It was also reported from Egypt and Namibia, but this material has been reassigned to other genera of beardogs.
Lokotunjailurus is an extinct genus of saber-toothed cats (Machairodontinae) which existed in Kenya and Chad during the Miocene epoch.
Enhydriodon is an extinct genus of mustelids known from Africa, Pakistan, and India that lived from the late Miocene to the early Pleistocene. It contains 9 confirmed species, 2 debated species, and at least a few other undescribed species from Africa. The genus belongs to the tribe Enhydriodontini in the otter subfamily Lutrinae. Enhydriodon means “otter tooth” in Ancient Greek and is a reference to its dentition rather than to the Enhydra genus, which includes the modern sea otter and its two prehistoric relatives.
Magericyon is an extinct genus of Amphicyonid ("bear-dog") that lived during the Miocene 10-9 Ma in what is now Spain.
Eomellivora is an extinct genus of prehistoric mustelids, closely related to the honey badger, known from Eurasia and North America, and tentatively Africa. It was one of the biggest mustelids ever known, bigger and more hypercarnivorous than the modern wolverine.
Mellivora benfieldi or Benfield's honey badger is an extinct species of mustelid from the Late Miocene and Early Pliocene of Africa and possibly Europe.
Ammitocyon is a genus of large sized carnivoran mammals, belonging to the Amphicyonidae, that lived during the Late Miocene in what is now Spain. It is notable for its extreme adaptations towards hypercarnivory, its extremely robust skeleton, and was one of the last surviving members of its family.
Asilifelis is an extinct genus of small felid that lived in what is now Kenya during the Early Miocene. Despite its fragmentary remains, it is remarkable because of its small size and advanced dentition. It contains a single species, Asilifelis cotae.
Myacyon is an extinct genus of large sized carnivoran mammals, belonging to the family Amphicyonidae, that lived in Africa during the Miocene epoch. Due to the limited scope and fragmentary nature of the severely damaged holotype, as well as the illustrations in its descriptions, which have been called inadequate, usage of this genus poses serious issues. However, it is notable for being one of the last surviving members of its family and its adaptions to hypercarnivory. Its relationships to other amphicyonids are obscure, and it is not closely related to Bonisicyon, the other late surviving African genus, although it has been proposed that it descends from a species of Cynelos or Namibiocyon.
Bonisicyon is an extinct genus of carnivoran mammals, belonging to the family Amphicyonidae. It is the last-surviving member of its family, living in East Africa during the end of the Miocene epoch. Known only from a damaged mandible and isolated teeth, its closer taxonomic affinities are unclear. It is notable for both its small size, and its unique dentition.
Namibiocyon is an extinct genus of carnivoran mammals, belonging to the family Amphicyonidae, that lived in Namibia during the Early Miocene epoch. Before the erection of this taxon in 2022, the type and only species, N. ginsburgi, had been assigned to a variety of other genera. It is notable for its adaptions toward hypercarnivory.
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