Meeting Abstract

81.1  Sunday, Jan. 6  The borderline between phylogeography and phylogenetics in the sesarmid crab Neosarmatium meinerti RAGIONIERI, L.*; FRATINI, S.; SCHUBART, C.D.; Univ. of Florence, Italy; Univ. of Florence, Italy; Univ. of Regensburg, Germany lapo.ragionieri@unifi.it

In recent years and with the aid of molecular techniques, it is often possible to identify geographically isolated populations within the distributionary range of widespread species, which can then be considered Evolutionary Significant Units (ESU). Mitochondrial genes are nowadays the most commonly employed markers in phylogeographic and phylogenetic studies, the difference between these fields only depending whether historical relationships are reconstructed within or between species. We present results of a phylogeographic study of a sesarmid crab, which is widespread in mangroves of the Indian Ocean, Neosarmatium meinerti (de Man, 1887). COI and 16S both revealed four different clusters: East African Coast; West Indian Ocean Islands, South Asia, Australia. They are separated by similar genetic distances from each other as the presumed sister species, Neosarmatium fourmanoiri Ser�ne, 1973. Similar geographic clusterisation has already been described in other widespread Indian Ocean species. In addition, we used a nuclear gene, 28S rRNA, for phylogeographic comparisons, obtaining an unexpected pattern of just two clusters within N. meinerti, one of which also included N. fourmanoiri. Within the Neosarmatium meinerti-fourmanoiri complex there are apparently two older lineages, of which one evolved two recognizable morphs, leading to the description of Neosarmatium fourmanoiri. Inclusion of additional species of Neosarmatium for phylogenies with mitochondrial and nuclear genes revealed that the ESUs recognized within N. meinerti are separable at a similar genetic level as currently valid species, providing a nice example of cryptic speciation in the marine environment.