Molecular analysis of Indo-Pacific Syllinae annelids with the description of five new species from the Philippine Islands.

Syllinae is the largest and the most diverse subfamily in Syllidae and usually a dominant group in many marine habitats, both in terms of numbers of species and individuals. However, the lack of morphological synapomorphies for many genera and the non-monophyly of most of these suggested by molecular studies, have stressed taxonomic and systematic problems within this subfamily. Although several studies have revised some genera in the Indo-Pacific area, important gaps of knowledge remain for this biogeographic region. Thus, in this study we undertook detailed morphological examination of Syllis and Megasyllis specimens from the Philippine Islands and provide a phylogenetic analysis of Indo-Pacific Syllinae in order to evaluate the position of newly described species. We provide line drawings, light microscopy observations and electron microscopy micrographs for eight species, including five new to science. Maximum likelihood and Bayesian inference analyses of four molecular markers (28S rRNA, 18S rRNA, 16S rRNA, cytochrome c oxidase subunit I) from 85 specimens are presented, showing the non-monophyletic status of Syllis and Megasyllis. Overall, our study increases the biodiversity of syllids in this poorly known Indo-Pacific area, highlighting the importance of examining both morphological and molecular data to expand our knowledge of the subfamily Syllinae and to further resolve the taxonomic issues that remain in this group. The following new taxa are described: Megasyllis kurui sp. nov. Moreno-Martínez, San Martín & Álvarez-Campos, Syllis ireneae sp. nov. Moreno-Martínez, San Martín & Álvarez-Campos, Syllis santii sp. nov. Moreno-Martínez, San Martín & Álvarez-Campos, Syllis tini sp. nov. Moreno-Martínez, Syllis walong sp. nov. Moreno-Martínez, San Martín & Álvarez-Campos. [ABSTRACT FROM AUTHOR]