The cryptic case of Otomys sloggetti (Sloggett’s vlei rat): Interpreting murid molar morphology in the fossil record

Vlei rats (Family: Muridae; Subfamily: Otomyinae) have a widespread distribution in southern Africa. They are favoured prey of barn and spotted eagle owls, frequently become associated with archaeological deposits when the owls roost cave sites. The phylogeny several Otomyinae species is enigmatic, Otomys sloggetti (Sloggett’s vlei rat) no exception. This has been referred to as ‘ice rat’ present ranges seemingly limited mountainous areas, at high altitude, Lesotho Drakensberg Karoo. It was thus surprising unexpected specimens closely resembling (identification based on molar morphology) were found sites south west coasts South Africa, also modern owl pellet assemblages – all extralimital current reported distribution. However, further examination comparison between these specimens, well extensive differences observed comparative from museum collections, highlighted potential problems common practice using tooth morphology identify fossil murid species. We identified six morphotypes material, which bore morphological resemblance O. sloggetti. material discussed this paper suggests that cryptic, undescribed rat species, or subspecies, past, may yet be, co-occurring populations karoensis irroratus. Phylogenetic studies need be done conjunction studies, as, currently, relationship huge variation seen interspecific genetics little understood, different not always distinguishable morphologically, considerable chromosomal polytypes found. Our findings highlight for cladistic genetic research Otomyinae.
 Significance:
 Mice shrews used by archaeologists indicators past climatic environmental conditions. Research into usually single site basis intersite comparisons rare. taxonomic conundrums presented African indicates such could result re-evaluation identifications, and/or indicate presence cryptic species/subspecies. needed variations (used taxa) understood. turn will help elucidate morphology, biogeography local adaptations.