Catalogus

Specimens belonging to a new species in the genus Protocirrineris have been found during surveys along the southwestern coasts of the Netherlands. Protocirrineris stormae sp. nov, as described herein, were collected from the muddy bottom sediments in enclosed marine waterbodies and estuaries. This species is characterized by branchiae commencing from the first chaetiger and tentacular filaments arranged in two groups arising from chaetigers 2–3 that present one/two pairs of lobes, each bearing a single dorsal tentacle. From the current records of this species, it seems that P. stormae has an affinity for enclosed marine environments or parts of estuaries with minimal variability in salinity, higher transparency, and normal temperature regime. The discovery and study of this species contributes to a comprehensive characterization of benthic fauna in locations subjected to particular environmental stresses. Considering the extensive dataset available from the Southwestern Netherlands due to many years of sampling, it is plausible that P. stormae is a pseudo-indigenous species as there seem to be no records of similar or unknown Protocirrineris before 2013.