Megalictis ferox
Encyclopedia
Megalictis ferox was a species of large predatory mustelid, now extinct, which existed in North America
during the "cat gap
" in the Miocene
period. It is thought to have resembled a large wolverine
, with a body mass of up to 60 kg.
was first described by W. D. Matthew in 1907, and assigned to the family Mustelidae
. Two similar genera discovered at the same time, Aelurocyon (Peterson, 1907) and Paroligobunis (Peterson, 1910) were identified as synonymous with Megalictis in 1996. P. R. Bjork
, in 1970, assigned the genus to the subfamily Mellivorinae, whilst J. A. Baskin reassigned it to Oligobuninae
in 1998. Two other species have been identified in the genus: Megalictis petersoni and Megalictis frazieri, whilst two more, Megalictis brevifacies and Megalictis simplicidens, have since been determined to be synonymous with Megalictis ferox. Other synonyms for the species include Aelurocyon brevifacies, Brachypsalis simplicidens and Paroligobunis simplicidens.
Specimens of the species have been found at ten sites in South Dakota
, Nebraska
and Wyoming
, dated to the Harrisonian period - from 24.8 to 20.6 million years ago. The 19 specimens so far identified have a wide range of sizes, which is believed to be evidence of extreme sexual dimorphism
, a phenomenon where males and females of the species will grow to different sizes; a 1996 study rejected the possibility of multiple "morphologically uniform" but differently sized species as unlikely. However, later studies identified significant morphological variation in the joints of the forearms, which would not be consistent with sexual dimorphism. suggests that the identification of all of these as a single species may need revision.
, whilst others suggest a less exceptional mass of 20-60 kg, compared to the wolverine of 10-20 kg. Ekorus ekakeran, a comparable mustelid of the same period found in Africa, is estimated to have been around 40 kg. Matthew described it as having short stout legs, with short feet and long non-retractible claws, similar to a modern wolverine
but about twice the size, and noted that "the teeth indicate an animal fully as predaceous as the wolverine, but the skeleton points to more fossorial habits". Research comparing the joints of the forelegs to modern mammalian carnivores suggests that it waited in ambush and grappled with its prey, rather than hunting it down by pursuit like a modern cheetah
.
North 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...
during the "cat gap
Cat gap
The cat gap is a period in the fossil record of approximately 25 to 18.5 million years ago in which there are few fossils of cats or cat-like species found in North America...
" in 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...
period. It is thought to have resembled a large wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...
, with a body mass of up to 60 kg.
Species identification
The genus MegalictisMegalictis
Megalictis is an extinct genus of large predatory mustelids, which existed in North America during the "cat gap" in the Miocene period.The genus was first described by W. D. Matthew in 1907...
was first described by W. D. Matthew in 1907, and assigned to the family Mustelidae
Mustelidae
Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...
. Two similar genera discovered at the same time, Aelurocyon (Peterson, 1907) and Paroligobunis (Peterson, 1910) were identified as synonymous with Megalictis in 1996. P. R. Bjork
Philip R. Bjork
Philip Reese Bjork is an American geologist and paleontologist known for his work in unearthing dinosaur species in America.-Career:Bjork received his undergraduate degree at the University of Michigan...
, in 1970, assigned the genus to the subfamily Mellivorinae, whilst J. A. Baskin reassigned it to Oligobuninae
Oligobuninae
Oligobuninae is an extinct subfamily of the Mustelidae family.The subfamily was described by J. A. Baskin in 1998, who assigned seven genera to it - Brachypsalis, Megalictis, Oligobunis, Paroligobunis, Potamotherium, Promartes, and Zodiolestes - representing thirteen separate species....
in 1998. Two other species have been identified in the genus: Megalictis petersoni and Megalictis frazieri, whilst two more, Megalictis brevifacies and Megalictis simplicidens, have since been determined to be synonymous with Megalictis ferox. Other synonyms for the species include Aelurocyon brevifacies, Brachypsalis simplicidens and Paroligobunis simplicidens.
Specimens of the species have been found at ten sites in South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
, Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....
and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, dated to the Harrisonian period - from 24.8 to 20.6 million years ago. The 19 specimens so far identified have a wide range of sizes, which is believed to be evidence of extreme sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, a phenomenon where males and females of the species will grow to different sizes; a 1996 study rejected the possibility of multiple "morphologically uniform" but differently sized species as unlikely. However, later studies identified significant morphological variation in the joints of the forearms, which would not be consistent with sexual dimorphism. suggests that the identification of all of these as a single species may need revision.
Physiology
Some writers suggest it could grow to the size of a black bearAmerican black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
, whilst others suggest a less exceptional mass of 20-60 kg, compared to the wolverine of 10-20 kg. Ekorus ekakeran, a comparable mustelid of the same period found in Africa, is estimated to have been around 40 kg. Matthew described it as having short stout legs, with short feet and long non-retractible claws, similar to a modern wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...
but about twice the size, and noted that "the teeth indicate an animal fully as predaceous as the wolverine, but the skeleton points to more fossorial habits". Research comparing the joints of the forelegs to modern mammalian carnivores suggests that it waited in ambush and grappled with its prey, rather than hunting it down by pursuit like a modern cheetah
Cheetah
The cheetah is a large-sized feline inhabiting most of Africa and parts of the Middle East. The cheetah is the only extant member of the genus Acinonyx, most notable for modifications in the species' paws...
.