A molecular framework for the phylogeny of Coralliophila and related muricoids

Coralliophilid gastropods include a large number of described species, grou ped in at least seven to 10 'genera according to their shell morphology. Th ey are considered closely related to Muricidae and ranked as a family on it s own or as a subfamily of muricids. Their phylogenetic position and relati onships are still not defined. The little anatomical work so far done on th is group seems to indicate a relatively high level of homogeneity. at least in the alimentary system. Then is a need for an independent phylogenetic f ramework to understand their position and relationship within the muricoide ans, and their internal systematics and phylogeny. We have addressed this p roblem by means of parsimony analysis of 609 aligned positions of the seque nces coding for the 12S rDNA. Four coralliophilid sequences representing th e same number of commonly recognized lineages (Babelomurex Latiaxis, Corall iophila, Galeropsis = Quoyula) were analysed, along with three sequences of muricoid genera (Stramonita. Phyllonotus. Nucella) representing as many su bfamilies of Muricidae, plus the sequence of the buccinoidean Fasciolaria a s outgroup. Maximum parsimony and neighbour-joining analysis of the dataset , with increasing weighing of transversions versus transitions, yielded sim ilar topologies. Two major outcomes resulted from the analyses: first, the coralliophilid sequences included herein are always monophyletic. with very high bootstrap support in all analyses. This is in agreement with the few anatomical data gathered so far that suggest coralliophilids are relatively homogeneous. Secondly. the sister-group of the coralliophilids among the a nalysed sequences is represented by Stramonita, with high bootstrap support in all analyses. This is in a good agreement with previous molecular analy ses and with the morphological evidence that Rapaninae are the closest sist er group of coralliophilids. According to the present results. the rank of the coralliophilids should be the same as Rapaninae, therefore a subfamilia l status (Coralliophilinae) seems reasonable.