Description of a new epibiotic relationship(Suctorian– Copepoda) in NE Atlantic waters:frommorphological to phylogenetic analyses

Abstract

Paraeuchaeta hebes is one of the most important carnivorous copepods in thecoastal upwelling system off Galician waters (Ría de Vigo,NEAtlantic).Asuc-torian epibiont of the genus Pelagacineta was found attached to the surface ofthese copepods. The abundance and distribution on the copepod surface wereanalysed, taking into account the sex of the crustacea n, revealing some prefer-ence for females and also a different attachment point in both sexes. The mor-phological study allowed us to identify a new species of this Suctoria epibiont asPelagacineta hebensis. Moreover, the 18S rRNA gene was partially sequenced toinspect the phylogenetic position of Pelagacineta hebensis within the subclassPhyllopharyngea. The maximum-likelihood (ML) tree obtained was consistentwith the morphological and w ith previous molecular studies and showed thatP. hebensis belongs to the order Endogenina, as a sister clade of the few taxa sequenced within this order. Including new genetic data to the Endogenina willallow building new hypothesis about the evolution of the most derived clade ofsuctorians.