title: Rapid radiation in spiny lobsters (Palinurus spp) as revealed by classic and ABC methods using mtDNA and microsatellite data.
abstract: BACKGROUND
  Molecular tools may help to uncover closely related and still diverging species from a wide variety of taxa and provide insight into the mechanisms, pace and geography of marine speciation. There is a certain controversy on the phylogeography and speciation modes of species-groups with an Eastern Atlantic-Western Indian Ocean distribution, with previous studies suggesting that older events (Miocene) and/or more recent (Pleistocene) oceanographic processes could have influenced the phylogeny of marine taxa. The spiny lobster genus Palinurus allows for testing among speciation hypotheses, since it has a particular distribution with two groups of three species each in the Northeastern Atlantic (P. elephas, P. mauritanicus and P. charlestoni) and Southeastern Atlantic and Southwestern Indian Oceans (P. gilchristi, P. delagoae and P. barbarae). In the present study, we obtain a more complete understanding of the phylogenetic relationships among these species through a combined dataset with both nuclear and mitochondrial markers, by testing alternative hypotheses on both the mutation rate and tree topology under the recently developed approximate Bayesian computation (ABC) methods.
  
  
  RESULTS
  Our analyses support a North-to-South speciation pattern in Palinurus with all the South-African species forming a monophyletic clade nested within the Northern Hemisphere species. Coalescent-based ABC methods allowed us to reject the previously proposed hypothesis of a Middle Miocene speciation event related with the closure of the Tethyan Seaway. Instead, divergence times obtained for Palinurus species using the combined mtDNA-microsatellite dataset and standard mutation rates for mtDNA agree with known glaciation-related processes occurring during the last 2 my.
  
  
  CONCLUSIONS
  The Palinurus speciation pattern is a typical example of a series of rapid speciation events occurring within a group, with very short branches separating different species. Our results support the hypothesis that recent climate change-related oceanographic processes have influenced the phylogeny of marine taxa, with most Palinurus species originating during the last two million years. The present study highlights the value of new coalescent-based statistical methods such as ABC for testing different speciation hypotheses using molecular data.
authors.affiliation: Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, Barcelona, Spain. fpalero@ist.ac.at
authors.forename: Ferran
authors.initials: F
authors.lastname: Palero
authors.forename: Joao
authors.initials: J
authors.lastname: Lopes
authors.forename: Pere
authors.initials: P
authors.lastname: Abelló
authors.forename: Enrique
authors.initials: E
authors.lastname: Macpherson
authors.forename: Marta
authors.initials: M
authors.lastname: Pascual
authors.forename: Mark A
authors.initials: MA
authors.lastname: Beaumont
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics*; D018895:Microsatellite Repeats; D009154:Mutation; D033521:Palinuridae / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny
chemical_list: D004272:DNA, Mitochondrial