Molecular phylogeny of echiuran worms (Phylum: Annelida) reveals evolutionary pattern of feeding mode and sexual dimorphism.

ABSTRACT: The Echiura, or spoon worms, are a group of marine worms, most of which live in burrows in soft sediments. This annelid-like animal group was once considered as a separate phylum because of the absence of segmentation, although recent molecular analyses have placed it within the annelids. In this study, we elucidate the interfamily relationships of echiuran worms and their evolutionary pattern of feeding mode and sexual dimorphism, by performing molecular phylogenetic analyses using four genes (18S, 28S, H3, and COI) of representatives of all extant echiuran families. Our results suggest that Echiura is monophyletic and comprises two unexpected groups: [Echiuridae+Urechidae+Thalassematidae] and [Bonelliidae+Ikedidae]. This grouping agrees with the presence/absence of marked sexual dimorphi

SUBMITTER: Goto R 

PROVIDER: S-EPMC3572977 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature