DNA barcoding of Cameroon samples enhances our knowledge on the distributional limits of putative species of Osteolaemus (African dwarf crocodiles)
Recent genetic and morphological evidence indicates that the African dwarf crocodile (O. tetraspis) is comprised of three highly divergent lineages: O. sp. nov., O. tetraspis and O. osborni. Their putative distributional limits correspond with the Cameroon volcanic line (CVL) and the Congo River basin. In this study, we expanded on previous phylogeographic work by conducting detailed sampling of this crocodile in Cameroon and around the CVL. We tested whether O. tetraspis is the only lineage occurring in Cameroon and whether the CVL represents the distributional limit between O. sp. nov. and O. tetraspis. We collected 65 tissue samples from individuals located throughout Cameroon, and the eastern and western sides of the CVL. We sequenced fragments of two mitochondrial genes (CO1 and 12S rDNA) and one nuclear gene (LDH-A). We found that O. tetraspis extends west beyond the CVL and, thus, this mountain chain does not represent the distributional limit of this lineage. We also found O. osborni in Cameroon. Our findings have important implications for the conservation and management of O. tetraspis lineages.
KeywordsConservation units Crocodylia Phylogeography Volcanic mountain chain
We attained approval and permits issued by Texas A&M University (TAMU) IACUC (AUP# 2010-123), Cameroon Ministries (MINRESI # 000064-2010, 000098-2011 and MINFOF# 0738-2010, 2149-2011) and US Fish and Wildlife Services (# 10US164015/9 – 2010, 11US47878A/9 - 2011). Funding was provided by TAMU Diversity Fellowship, Alfred P. Sloan Foundation Minority Ph.D. Program in Mathematics, Science and Engineering, Rufford Small Grants for Conservation of Nature, Student Research Assistance Scheme of the Crocodile Specialist Group-IUCN, and the L.T. Jordan Fellowship for International Awareness (TAMU). This is publication number 1475 of the Biodiversity Research and Teaching Collections.
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