Rugosoannulata

Rugosoannulata is a small, cylindrical annelid worm belonging to the family Pectinariidae in the class Polychaeta. First described in 1895 by the Russian zoologist F. I. Karmovskaya, the species is known for its distinctly rugose dorsal surface, which gives the genus its name. Adult individuals range from 3 to 6 centimeters in length and possess a series of parapodia that aid in locomotion through sediment. The worm’s exoskeleton is composed of a tough, silica‑laden cuticle that provides protection against predators and abrasive substrates.

The species is primarily found in shallow marine environments along the temperate coasts of the northern Atlantic, including the Bay of Biscay and the North Sea. Rugosoannulata inhabits sandy to muddy bottoms, where it constructs shallow burrows and engages in deposit feeding. Its diet consists mainly of detritus, microalgae, and small invertebrate fragments, which it ingests while moving slowly along the surface of the substrate. The worm’s reproductive strategy is hermaphroditic; gametes are released into the water column during spawning seasons in late spring, after which fertilized larvae develop into planktonic zooplankton before settling into benthic juveniles.

Ecologically, Rugosoannulata plays a role in bioturbation, altering sediment structure and nutrient fluxes. The species is considered a bioindicator for sediment health due to its sensitivity to pollution and changes in sediment composition. While not of commercial importance, it is frequently cited in studies of annelid physiology and marine sediment dynamics.