Reanalysis of African Elephas recki: implications for time, space and taxonomy

The African Elephas lineage, consisting of E. ekorensis, E. recki, and E. iolensis, is an important faunal component of Plio-Pleistocene African paleontological localities. Species within the lineage have been used as biochronological markers, particularly the intermediate member, E. recki which is divided into five time-successive subspecies. This lineage has been proposed as an example of anagenetic change, with each species and/or subspecies evolving directly into the next with no overlap in time, thus marking its utility for biostratigraphy. Consolidation of the published records of E. recki subspecies indicate that the ranges for all five subspecies overlap. Comparison of dental variation in E. recki to extant elephant species as well as African and Eurasian fossil elephants indicate that the variation in E. recki exceeds that of many other species, with significant variation at the subspecies level as well. The degree of temporal overlap and morphological variation in E. recki suggests that this is not a single species. Morphological characters and measurements were reassessed for their utility in delineating species and subspecies, and a preliminary revision of the sample of specimens attributed to E. recki is discussed. Revision of the African Elephas lineage should be done in conjunction with reanalysis of the other elephantid lineages, and will have important implications for elephantid diversity, evolution and biochronology in the African Plio-Pleistocene.