UC San Diego

Galapagomystides is an exclusively deep sea group of phyllodocid annelids, originally erected for Galapgomystides aristata from hydrothermal vents of the Galapagos Rift. In this study, numerous specimens of Phyllodocidae collected from hydrothermal vents and methane seeps from the Pacific Ocean, including specimens that are likely to represent Galapgomystides aristata, were studied using morphology (light microscopy and scanning electron microscopy) and DNA sequence data. Phylogenetic analysis of the newly generated molecular data (cytochrome c oxidase subunit I, 16S rRNA, 18S rRNA, and 28S rRNA) combined with an already available extensive dataset for Phyllodocidae resulted in a monophyletic Galapagomystides. Two new species from hydrothermal vents in the West Pacific, G. bobpearsoni n. sp., and G. kathyae n. sp., as well as one new species from a cold seep in the East Pacific, G. patricki n. sp. were inferred from the phylogenetic results and morphology. These new species are formally described, and a previously known vent species, Protomystides verenae, is redescribed and transferred to Galapagomystides. Galapagomystides verenae was found to occur in both vents and seeps in the eastern Pacific, from Oregon to Costa Rica. The diagnosis of Galapagomystides is amended and the biogeography and habitat evolution of the five species of Galapagomystides is discussed. This study reinforces the conception that species within the genus Galapagomystides likely feed on the blood of tube worms, resulting in the colloquial name applied here, “vampire worms”.