Phylogenetic analysis of oligochaete Tubificinae (Annelida:Clitellata) based on mitochondrial sequence data

Abstract

Partial sequences of the mitochondrial genes 16S rRNA and cytochrome c oxidase subunit I (COI) were used (1) to resolve the internal relationships of the subfamily Tubificinae (Annelida : Clitellata) and (2) to test the existence of cryptic species within the stygobiont oligochaete Troglodrilus galarzai (Giani & Rodriguez, 1988). Phylogenies were estimated using maximum likelihood, Bayesian inference and parsimony. Although trees were incompletely resolved at intergeneric level, a close relationship between Heterochaeta Claparède, 1863 and Troglodrilus Juget, des Châtelliers & Rodriguez was revealed, and the separation of Lophochaeta ignota Štolc, 1886 and Heterochaeta costata Claparède, 1863 from Tubifex Lamarck, 1816 was corroborated by mitochondrial molecular data. Maximum genetic divergence between allopatric populations of T. galarzai was 18% for COI (uncorrected pairwise distance), suggesting cryptic speciation within this nominal species.