A new species of Phyllochaetopterus (Chaetopteridae: Annelida) from near hydrothermal vents in the Lau Basin, western Pacific Ocean

Phyllochaetopterus lauensis n. sp., a new species of Chaetopteridae, is described from material collected by the DSV Jason II from the vicinity of hydrothermal vents in the Lau Basin, western Pacific Ocean. The new species is characterized by the coloration and patterning of the ventral shield of the anterior region (region A), the presence of one large cutting chaeta on each parapodium of the fourth chaetiger (A4), the shape of these A4 cutting chaetae (with a pear-shaped head), and presence of two middle-region (region B) chaetigers with foliose notopodia. The new species is very similar to some Spiochaetopterus species, but belongs in Phyllochaetopterus based on its possession of a pair of anterior ‘antennae’, which are in fact cirri of chaetiger one with internal chaetae. The new species is compared to other Phyllochaetopterus species, particularly from the Pacific, and we provide a table for all species currently referred to the genus.