Taxonomic review of fossil Proboscidea (Mammalia) from Langebaanweg, South Africa

Abstract

Comparative morphological and metric study of proboscidean dental fossils from the Quartzose (QSM) and Pelletal Phosphate (PPM) Members of the Varswater Formation at Langebaanweg, South Africa identifies the presence in the fauna of an anancine gomphothere and two species of elephant. The gomphothere, from the QSM and PPM, displays a unique combination of primitive and derived molar features, and consequently is placed in a new species (Anancus capensis sp. nov.) that is regionally distinct from other African species of Anancus. A new species of loxodont elephant (Loxodonta cookei sp. nov.) is identified from the PPM, distinguished from penecontemporaneous L. adaurora by having anterior and posterior accessory central conules that contribute to the formation of strong median sinuses throughout its molar crowns. It is further differentiated from other loxodont elephants by its primitive retention of permanent premolars, lower crown height, fewer molar plates, thicker enamel, and lower lamellar frequency, and extends the L. exoptata-L. africana lineage back into the late Miocene. A second elephant species, from the QSM, is referable to Mammuthus subplanifrons, and represents the most archaic stage of mammoth evolution. The elephants appear to have been more cosmopolitan in distribution than the gomphothere. Together, these taxa support a latest Miocene-early Pliocene age of ca. 5.0 Ma for the Vars-water Formation. Based on isotopic analyses of congeners from other African sites, it may be inferred from the occurrence of these taxa that open conditions were present locally and abundant grazing resources were available in the ecosystems of Langebaanweg during the time of deposition of the QSM and PPM.