The phylogeography of Lemniscomys striatus (Rodentia: Muridae) confirms a remarkable vicariant event in neighbouring savanna populations in Central Gabon

Abstract

Our recent phylogeographic study on the strictly savanna small rodent Nannomys  minutoides revealed an unexpected pattern of divergence between populations  occupying neighbouring savanna islands in Central Gabon, suggesting the historical and continuing fragmentation of these savanna habitats. In this study, we test this hypothesis using comparative phylogeography with another species of savanna  rodent, Lemniscomys striatus, using nested clade analysis (NCA) on cytochrome b sequences of 53 individuals, particularly checking for vicariance patterns in the Lopé National Park region. Lemniscomys striatus is characterized by a local  structured pattern similar to that of N. minutoides. These new results further support the scenario of historical and ongoing fragmentation of the local savanna landscape which commenced in the upper Pleistocene, despite the repetitive savanna expansion episodes as documented by the landscape history. Geographic barriers most likely comprising forested areas, which prevent the mixing of local savanna rodent populations, must have persisted in this region. The presence of these  barriers could not have been inferred from global paleoclimatic and  paleoenvironmental analyses alone.

Key words: Lemniscomys striatus, fragmented landscape, nested clade analysis, cytochrome b, Pleistocene.