Amphiorycteropus undetermined

Lehmann, Thomas, 2009, Phylogeny and systematics of the Orycteropodidae (Mammalia, Tubulidentata), Zoological Journal of the Linnean Society 155 (3), pp. 649-702 : 673

SPECIES AMPHIORYCTEROPUS SP. ROOILEPEL

Material (the specimens have not been directly seen by the author): Elements of a skeleton ( RL 4 ′95) with fragment of mandible, parts of a femur, a tibia, a talus, vertebrae, and phalanx; the distal epiphysis of a metatarsal bone ( RL 37 ′95); and a fragment of a left mandible ( RL 43 ′95), described by Pickford (1996) as ‘ Orycteropus cf. minutus ’. The material is housed at the National Earth Science Museum, Windhoek ( Namibia) .

Locality and age: The specimens have been found at Rooilepel, close to the Orange River ( GPS: 28°17′56″S, 16°35′01″E) ( Namibia). Pickford (1996) wrote that the fossil aardvarks have been found in three different stratigraphic levels: 15–14 Mya, 12–11 Mya, and 11–10 Mya, but did not specify in which unit each specimen has been found .

Discussion: The isolated mandible and metatarsal are too fragmentary to enable a reliable identification, and could be placed in Orycteropodidae sp. indet. Nonetheless, they are tentatively associated with the more complete specimen RL 4′95, which shows some remarkable features. No molars are known, but some premolars of unknown position are still present in the mandible. Their size (after Pickford, 1996) is larger than that of the premolars found in Arrisdrift (see below), is close or slightly larger than that in Myorycteropus (P 3 and P 4), and is close or slightly smaller than the size of the P 2 and P 3 in Amphiorycteropus . Unfortunately, there are no premolars known for aff. M. minutus , so far. The Rooilepel premolars are more or less intermediate between Myorycteropus and Amphiorycteropus . The size of the premolars is nonetheless of only limited value for the identification of the specimens. The talus of that specimen presents, according to Pickford (1996: fig. F), a concave and developed cotyloid facet for the medial malleolus of the tibia. This feature alone helps us to distinguish these specimens from Myorycteropus , which shows the derived state for that character (vertical and negligible facet). Therefore, the Rooilepel aardvarks are cautiously attributed to the genus Amphiorycteropus , but remain undetermined at the species level until further material is discovered. Pickford (1996) also reported parts of the femur and tibia for that specimen, but only described them briefly. A revision of these elements might give us new clues for the identification of these Namibian aardvarks.