Taxonomic history In 1858, the paleontologist Joseph Leidy described a new species of cat,
Felis intrepidus, based on lower jaw fragments (a left ramus, described, and a right ramus, mentioned only and now lost) found somewhere in Nebraska near the Niobrara river. The fragments were later determined to have come from the lower
Valentine Formation, making them late Barstovian in age. Leidy reassigned the specimens to
Pseudaelurus as
Pseudaelurus intrepidus in a 1869 paper. In 1873, an expedition collected another lower jaw from the lower Valentine Formation, which was described by Thorpe in 1922 as the holotype of the new species
Pseudaelurus marshi. He also described a paratype, a left ramus collected from part of the
Ogallala Group (also of Barstovian age). Shortly after, he also described
Pseudaelurus thinobates, a larger species from a late Clarendonian locality in California. However, David Kitt removed
Pseudaelurus thinobates from the genus, placing it instead as
Nimravides thinobates, during a 1958 study. Subsequently, a review of the genus reassigned
Pseudaelurus pedionomus to the new genus as
Nimravides pedionomus. The fragment remained the only specimen assigned to
Ps. aeluroides, and an examination of illustration and measurements of the fragment in 2003 lead Tom Rothwell to suggest that it actually belonged to a juvenile
Ps. marshi. Similar in size to
Nimravides pedionomus, this was referred in 2003 to
Nimravides hibbardi instead. He also referred a number of other specimens, collected from early Barstovian localities in Nebraska and New Mexico and from late Barstovian localities in New Mexico and Colorado, to
Pseudaelurus stouti. However, this was largely ignored by later studies until a 2010 review of the Felidae as a whole brought up the proposal again, leading to some authors, though not all, recognizing the generic split. ==Description==