On a new species of Spirobranchus (Annelida: Serpulidae) and considerations on the genus along the Brazilian coast

摘要

Spirobranchus are abundant and diverse serpulids in tropical regions, with three species reported in Brazil, which occurrence is questionable, due to their distant type localities. In the present work, we describe a new species of Spirobranchus from the Brazilian coast and report the other species of the genus occurring off Brazilian shoreline, based on specimens from different locations. Specimens were collected in the states of Alagoas, Rio de Janeiro, and Santa Catarina, sorted and analyzed under a stereoscopic microscope. Then, the animals were anesthetized and subsequently fixed and prepared for the scanning electron microscopy. Specimens from the Caribbean and other Brazilian states were loaned from Museu Nacional of Universidade Federal do Rio de Janeiro, Universidade Estadual do Rio de Janeiro and Universidade Federal de Alagoas. Morphological analyzes differentiated the three species and provided details of the morphology that can be used in the future taxonomy of the family. The species S. giganteus and S. tetraceros are more similar to each other, but can be readily separated based on the spiral radiolar crown in the former; S. minutus differs from the other species for the tube, operculum, and type of uncini. Spirobranchus lirianeae sp. nov. nests within S. kraussii-complex, with a concave operculum, absence of collar chaetae and paired compound eyes on the radioles, differing by being a solitary rather than a gregarious species, by the funnel-shaped operculum, fringed tonguelets and tube with single keel, distally pointed.