Molecular phylogeny of the East Pacific Rise squat lobsters of the genus Munidopsis (Decapoda, Galatheidae) with the description of seven new species.

Abstract

Numerous specimens of the genus Munidopsis from the East Pacific, and including the East Pacific Rise (EPR), are reviewed using morphological characters and mitochondrial cytochrome oxidase subunit I (COI) sequences. Six new Munidopsis species from the East Pacific are described (M. bracteosa, M. hirsuta, M. kensmithi, M. scotti, M. segonzaci, and M. tiburon), and the status of M. recta is revised. A seventh new species (M. vrijenhoeki) from Fiji Basin (SW Pacific) is also included. A combined morphological and molecular analysis revealed that the most common species on the EPR is Munidopsis recta. Most of the new species can be differentiated from closely related species by subtle morphological characters, which correspondingly match the molecular phylogeny and large molecular divergence, confirming the existence of sibling species in the genus Munidopsis. Most Munidopsis individuals formerly considered M. subsquamosa from the East Pacific Rise appear to be members of M. recta. One potential sister taxa to M. recta is M. bracteosa, which is found at the Juan de Fuca hydrothermal vents, the Mendocino Fracture Zone, and a Monterey Bay whalefall. Our findings suggest that Munidopsis populations are tightly interconnected between distant and discrete locations, and challenge models for the predicted dispersal of these species. Additional sampling of Munidopsis populations on localized habitats (wood, hydrothermal vents, and whale falls), as well as intervening abyssal areas, are required to fully understand the complex evolutionary history and diversity of this group.