At least some meiofaunal species are not everywhere. Indication of geographic, ecological and geological barriers affecting the dispersion of species of Ototyphlonemertes (Nemertea, Hoplonemertea)

Most meiofaunal species are known to have a broad distribution with no apparent barriers to their dispersion. However, different morphological and/or molecular methods supported patterns of diversity and distribution that may be different among taxa while also conflicting within the same group. We accurately assessed the patterns of geographic distribution in actual genetic species of a marine meiofaunal animal model: Ototyphlonemertes. Specimens were collected from several sites around Europe, Northern and Central America, Southern America, Pacific Islands and Asia. We sequenced regions of two mitochondrial and two nuclear genes. Using single-gene, a concatenated data set, multilocus approaches and different DNA taxonomy methods, we disentangled the actual diversity and the spatial structures of haplotypes and tested the possible correlation between genetic diversity and geographic distance. The results show (i) the importance of using several genes to uncover both diversity and highli...