A scaleless scale worm: Molecular evidence for the phylogenetic placement of Pisione remota (Pisionidae, Annelida)

摘要: Pisionidae is a group of interstitial worms whose phylogentic affinities have been enigmatic. They allied to different Phyllodocida taxa. Although originally associated with Glyceridae and Phyllodocidae, they are more recently considered be related scale worms. Scale well-defined taxon, Aphroditiformia, within Annelida due the unique possession dorsal scales called elytra. lack elytra but grouped because possess two pairs jaws venom glands, also found in Glyceridae. Determining phylogenetic position important for understanding if features such as venomous evolutionarily labile annelid history. Therefore, we explored 18S rDNA Cytochrome c Oxidase subunit I data from several Pisionidae, other determine placement Pisionidae. Maximum likelihood Bayesian inference separate combined sets were conducted. All analyses support derived close Pholoidae Sigalionidae. The loss probably adaptation life. Furthermore, results reject monophyletic Aphroditoidea comprising Acoetidae, Aphroditidae, Eulepethidae Polynoidae. Thus, only simple chaetae either symplesiomorphic or convergent.