Phylogenetic position of Pelusios williamsi and a critique of current GenBank procedures (Reptilia: Testudines: Pelomedusidae)

Abstract

We re-examine the phylogenetic position of Pelusios williamsi by merging new sequences with an earlier published data set of all Pelusios species, except the possibly extinct P. seychellensis, and the nine previously identified lineages of the closely allied genus Pelomedusa (2054 bp mtDNA, 2025 bp nDNA). Furthermore, we include new sequences of Pelusios broadleyi, P. castanoides, P. gabonensis and P. marani. Individual and combined analyses of the mitochondrial and nuclear data sets indicate that P. williamsi is sister to P. castanoides, as predicted by morphology. This provides evidence for the misidentification of GenBank sequences allegedly representing P. williamsi. Such mislabelled GenBank sequences contribute to continued confusion, because only the original submitter can revise their identification; an impractical procedure impeding the rectification of obvious mistakes. We recommend implementing another option for revising taxonomic identifications, paralleling the century-old best practice of natural history museums for new determinations of specimens. Within P. broadleyi, P. gabonensis and P. marani, there is only shallow genetic divergence, while some phylogeographic structuring is present in the wide-ranging species P. castaneus and P. castanoides. © 2012 Koninklijke Brill NV, Leiden.