Hemimachairodus

The species was originally described in 1934 by German palaeontologist Gustav Heinrich Ralph von Koenigswald under the name Epimachairodus zwierzyckii.[2] He referred to it again by that name in 1940.[3] A 1962 study by Bjorn Kurtén referred to it as Homotherium zwierzyckii but stated that it was certainly not a member of Homotherium and instead recommended assigning it to the genus Megantereon.[4]

In 1974, Koenigswald described more fossils that he assigned to the species, and named the new genus Hemimachairodus.[5]

The specific epithet was given in honor of the Polish geologist Józef Zwierzycki.[6]

Koenigswald's 1974 diagnosis of Hemimachairodus noted the complete reduction of the third premolar, and serrations on the upper canine teeth being limited to the inner edge.[5]

The holotype of Hemimachairodus zwierzyckii is a partial left mandibular ramus, retaining the first incisor, the canine, and the fourth premolar, after which it is broken. Koenigswald in 1974 described it as having a weak mental process and a strongly developed mental crest. The mandible itself is slender, with a 46mm diastemata. It was recovered from Sangiran in central Java.[5]

From Sangiran, Koenigswald (1974) also described a second partial jaw fossil, broken about 1cm behind the molar and 2cm in front of the premolar and retaining both teeth; one tip and one complete lower canine; and two fragments of an upper canine tooth. And from the Djetis Beds Modjokerto in eastern Java, a fragment of a mandible retaining a premolar and the front half of a molar.[5]