Species discrimination and phylogenetic analysis of the spear lobsters linuparus (palinuridae,decapoda)

Linuparus White, 1847 comprises three extant species, Linuparus trigonus (Von Siebold, 1824), L.sordidus Bruce, 1965, and L.somniosus Berry and George, 1972. These extant species are distributed in Indo-West Pacific.Specimens from Northern Hemisphere are generally darker in colour for both L.trigonus and Lsordidus. Mitochondrial 12S rRNA and COI genes of these specimens were studied and the phylogenetic tree was constructed. The color forms of L.sordidus are genetically homogenous, whereas those of L.trigonus are genetically distinct at the species level. Consistent differentiation in the shape of thoracic sternum between the two colored forms further supports the occurrence of cryptic species in Ltrigonus. The paler form distributed in the Southern Hemisphere is described as a new species L.meridionalis. The phylogenetic relationship also demonstrates that L.somniosus is basal whereas L.trigonus and L.meridionalis sp.nov, are derived sister taxa.