No abstract

Spatial genetic studies often require sampling broadly separated areas, difficult to access simultaneously. Although comparing localities surveyed at different time periods might result in spurious genetic differentiation, there is a general believe on the stability of genetic structure through time, particularly if sampled localities are isolated or very distant. By analysing spatial and temporal genetic differentiation of the portunid crab Liocarcinus depurator we assessed the contribution of historical and contemporary processes on population connectivity patterns across three main oceanographic discontinuities along the Atlantic-Mediterranean transition: Gibraltar Strait, Almeria-Oran Front and Ibiza Channel. A partial fragment of the cytochrome oxidase I gene was sequenced in 366 individuals collected from localities at both sides of each discontinuity during three time periods. Although localities showed genetic fluctuations through time, a significant gradient was detected along the coast for all sampling periods. Significant inter-annual differences identified within the Alicante area, north of the Almeria-Oran Front, were associated with shifts in the relative contribution of Atlantic and Mediterranean water masses. The persistence of a clinal pattern in the Atlantic-Mediterranean transition area together with local fluctuations suggests a complex balance of dispersal and selection.

The genus Galathea is one of the most speciose and unwieldy groups in the family Galatheidae. The examination of more than 9000 specimens of 144 species collected in the Indian and Pacific Oceans using morphological and molecular characters, has revealed the existence of 92 new species. The specimens examined during this study were obtained by various French expeditions supplemented by other collections from various sources, and including the type specimens of some previously described species. Most of the new species are distinguished by subtle but constant morphological differences, which are in agreement with molecular divergences of the mitochondrial markers COI and/or 16S rRNA. Here, we describe and illustrate the new species and redescribe some previously described species for which earlier accounts are not sufficiently detailed for modern standards. Furthermore we include a dichotomous identification key to all species in the genus from the Indian and Pacific Oceans.

Squat lobsters have a worldwide distribution and are highly visible crustaceans living in a broad range of habitats. In this study, partial sequences of two mitochondrial DNA genes (16S rRNA and COI) and a nuclear gene (H3) were obtained for all but one of the known species of the shallow-water genera Sadayoshia (Munididae) and Lauriea, Macrothea and Triodonthea (Galatheidae). Lauriea siagiani appeared to be phylogenetically closer to Triodonthea and Macrothea than to other Lauriea species, suggesting the need for taxonomic re-evaluation of these taxa. All species of Sadayoshia formed a monophyletic group that would have diverged during the Paleogene (around 50Mya). Our results support the hypothesis that the late Paleogene-Neogene transition was a period of rapid diversification for shallow-water species of both Galatheidae and Munididae in the Indo-Pacific region. This is probably related to high tectonic activity among the Eurasian, Philippine Sea, Indo-Australian and Pacific plates and corresponding changes in distribution of habitats and ocean currents during the late Paleogene. Finally, the tropical south-west Pacific province is identified as a major diversification centre for shallow-water squat lobsters, from where species dispersed to other Pacific and Indian Ocean regions

The genus Lauriea belongs to the family Galatheidae and is easily differentiated from other genera of the family by the endopod of the uropod being much wider than long and the dactyli of the walking legs being curved and strongly biunguiculate. Examination of many specimens collected during recent expeditions from Madagascar to French Polynesia and using morphological and molecular data revealed the existence of six species, five of them new, that are genetically distinct yet morphologically very similar. Furthermore, another new species, having a triunguiculate P2-4 dactyli, represents a new genus, Triodonthea.