Megalictis (meaning "great weasel") is an extinct genus of large predatory 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 .
History of discovery
The genus
Megalictis was first described by W. D. Matthew in 1907, and assigned to the family
Mustelidae.
[Paleobiology Database] Two similar genera discovered at the same time,
Aelurocyon (Peterson, 1907) and
Paroligobunis (Peterson, 1910) were identified as synonymous with
Megalictis in 1996
[Andersson, p.39] though
Paroligobunis was re-established as a separate genus in 1998.
P. R. Bjork, in 1970, assigned the genus to the subfamily
Mellivorinae,
[Bjork, p.18] whilst J. A. Baskin reassigned it to
Oligobuninae in 1998.
Three species have been identified in the genus:
M. ferox,
M. petersoni, and
M. frazieri, whilst two more,
Megalictis brevifacies and
Megalictis simplicidens, have since been determined to be synonymous with
M. ferox. Other synonyms of
M. ferox include
Aelurocyon brevifacies,
Brachypsalis simplicidens and
Paroligobunis simplicidens.
Specimens of M. ferox 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.[Hunt & Skolnick, quoted Andersson, p.39-40] However, later studies identified significant morphological variation in the joints of the forearms, which would not be consistent with sexual dimorphism. Andersson suggests that the identification of all of these as a single species may need revision.[Andersson, p.11 & p.40]
Description
Megalictis was one of the largest terrestrial mustelids ever recorded, surpassing in size other mustelids like
Ekorus,
Eomellivora, and
Plesiogulo.
Recovered skulls of
Megalictis ferox had similar condylobasal lengths to small modern jaguars, ranging from in length, and were almost as wide in mastoid width as those of some
Ursus americanus, ranging from wide. The enlarged anterior edge of the cornoid process confers a wide gape relative to its short rostral length, suggesting
Megalictis possessed a powerful bite force; together with blunt, stout postcanine teeth,
Megalictis was well equipped to engage in
osteophagy, similar to modern
hyenas and
wolverines.
[ It has been described as having short stout legs, with short feet and long non-retractible claws, similar to a modern ferret but about twice the size,][Quoted in Gratacap, p.921] 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.[Hopkin]
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