Bristle worms of the family Onuphidae are very abundant and diverse both in shallow waters and deep sea playing a significant role in many benthic communities. Being very widespread in Norwegian waters, onuphids are commonly present in sediment samples us ed in ecological studies and environmental monitoring surveys. Onuphid worms represent a unique example among annelids of a remarkable morphological, reproductive and behavioral diversity. Several genera of onuphids display signs of progenetic origin howe ver their phylogenetic position within the family is not resolved. The proposed project aims to study the evolution of morphology and adaptive strategies within the family utilizing a phylogenetic approach. It is planned to reconstruct phylogeny of onuphi d worms based on molecular data (18S rDNA and 16S rDNA) and compare it with existed morphology-based phylogenies. Sequences of both genetic markers for 37 species of onuphids representing 13 genera became available during previous research. During the mob ility part of the project at the University Museum of Bergen it is planned to focus on the molecular analyses of genera with suggested progenetic origin. Materials from a number of Norwegian, Russian and international expeditions will be examined and use d for DNA extraction, amplification and sequencing. Prof. Endre Willassen will supervise the research project and assist with phylogenetic analyses. The result of the project will: (1) contribute to taxonomical revision of onuphids; (2) advance knowledge in polychaete phylogeny and evolution; (3) contribute to understanding of the role of progenesis in marine organisms as one of evolutionary processes shaping life in the ocean.