We describe
Dysponetus joeli sp. nov. from shallow maerl habitats in the north-east Atlantic (English Channel and Bay of Biscay).
Dysponetus joeli differs from congeneric species by a unique combination of characters, including a large syllid-like pharynx, 2-4 simple serrated neurochaetae (closely similar to notochaetae, but much smaller and more delicate), D-shaped chaetal spines and ventral cirri on the third segment. A phylogenetic parsimony analysis based on morphological traits suggests that
Dysponetus is not monophyletic unless it includes the closely related genera
Vigtorniella and
Pseudodysponetus, which are well delineated inside the dysponetid clade. Chaetal spines seem to be secondarily derived from paleae and to have originated in infaunal dysponetid forms. They should not be considered as plesiomorphic, but as evidence to support the clade made up by
Dysponetus-
Vigtorniella and
Pseudodysponetus as delineated by a phylogenetic analysis.
