In the third edition of Walker's Mammals of the World,
Bronner and Jenkins (2005) list 21 species of recent golden moles (Chrysochloridae, Afrotheria), all but three of which are known from the southern African mainland in the five countries at or below the 20th parallel. Two species (Chrysochloris stuhlmanni and Calcochloris leucorhinus) are known from equatorial localities in and near Cameroon, DRC, and the countries surrounding Lake Victoria. A third "northern" taxon, Calcochloris tytonis, is represented by a jaw and partial skull from a single owl pellet from Somalia (Simonetta 1968).
Extinct golden moles of unquestionable family-level affiliation are limited to just four named species: Prochrysochloris miocaenicus (Butler 1984), Proamblysomus antiquus, Chlorotalpa spelea (Broom 1941), and Amblysomus hamiltoni (De Graaff 1957). The former is from early Miocene localities in Kenya, and the latter three are from the Plio-Pleistocene of South Africa.
Mein and Pickford (2003) referred additional remains from the middle Miocene of Namibia to Prochrysochloris sp. Golden mole fossils are not uncommon from late Miocene to Recent fossil localities in southern Africa (cf.
Avery 2000). However, they are rarely assigned to an explicit, named species due to the fragmentary condition of their remains.
Seiffert et al. (2007) described a fragmentary jaw that they argued might be the oldest relative of the group, Eochrysochloris tribosphenus, from the Eo-Oligocene of northern Egypt. They referred two specimens to this species, which (as the specific epithet implies, and in contrast to any known chrysochlorid) show basined talonids on p4 and m2 (other cheek teeth are incompletely known). No features of the highly derived coronoid or angular processes of chrysochlorids are adequately preserved in these specimens to unambiguously infer their anatomy. It is reasonable to expect that chrysochlorid fossils will be found at some point during the Paleogene and in some place on the African continent, such as the Eocene-Oligocene boundary in northern Egypt. Nevertheless, the anatomical basis for doing so is not yet definitive.
Biogeographically, it is even less surprising to document the occurrence of fossil chrysochlorids in the early Pliocene of Western Cape Province, South Africa. Here we describe isolated, but intact and numerous, cranioskeletal elements of golden moles from the site of Langebaanweg. Although without direct associations between elements, the numerically most common jaws, maxillae, ear ossicles, pelvic, fore- and hind-limb elements closely resemble in size and shape the living Cape golden mole, Chrysochloris asiatica. An exception to this generalization is that the most common humeral type shows a significantly narrower distal humerus (i.e., the distal margin from the tip of the medial epicondyle, including the trochlea and capitulum, to the supinator crest; see
Figure 1) than that exhibited by C. asiatica and most other golden moles. In addition, two out of over 100 jaw fragments (including over 40 relatively complete dentaries) preserving anterior teeth and/or alveoli show an enlarged, very robust second lower incisor. Finally, a small number of limb elements (but no craniodental elements) represent a substantially larger golden mole than the extant C. asiatica. We argue that these differences justify the assignment of the Langebaanweg chrysochlorid fossils to at least three species, two of which are represented by sufficiently high-quality material to be named in this paper.