Antemus chinjiensis, Jacobs, 1977

Antoñanzas, Raquel López, 2009, First Potwarmus from the Miocene of Saudi Arabia and the early phylogeny of murines (Rodentia: Muroidea), Zoological Journal of the Linnean Society 156, pp. 664-679 : 672

ANTEMUS CHINJIENSIS JACOBS, 1977

This species was erected by Jacobs (1977) on the basis of four isolated cheek teeth (2M1, 1M 2, 1m 2). The holotype is a right M1 (YGSP 7649) from the Middle Miocene YGSP locality 41, Chinji Formation, Punjab, Pakistan ( Jacobs, 1977). More specimens of this taxon have been also collected in Pakistan in the Chinji Formation at Middle Miocene YGSP localities 430 (close to locality 41) and 491 (near the village of Kamlial) ( Jacobs et al., 1989), at locality PMNH 8608 (Dhok Tahlian area) ( Cheema, Raza & Rajpar, 1996), and at locality H-GSP 107, near Banda Daud Shah ( Wessels et al., 1982).

The cheek teeth of this taxon are larger than those of Potwarmus flynni sp. nov., and their morphology is also very different. The M1 of Antemus chinjiensis shows the basic murine pattern of three chevrons. The first one is formed by the connection of three cusps (anterostyle, lingual and labial anterocones), the second one includes a large isolated enterostyle, and connected paracone and metacone, and the third one has two cusps (hypocone and metacone) with no trace of posterostyle. In contrast, AJ7 has a much smaller anterocone and enterostyle, the cusps are more alternate, and it lacks a well-developed anterostyle. The M2 of A. chinjiensis is also very different, having a labial anterocone, a very large enterostyle, and a metacone connected to the hypocone. In AJ7, the labial anterocone is lacking, the enterostyle is small, and the metacone joins with the posterior cingulum, but not with the hypocone. The m1 of A. chinjiensis is less reduced than AJ13, having a bilobed anteroconid separated by a deep furrow. Labial accessory cusps may be present in A. chinjiensis whereas they are absent in AJ13.