Cirratulidae (Polychaeta) from austral regions: Cirratulus species from Argentina, with the description of new species.

SARACHO BOTTERO, M.A.; ELIAS R; MAGALHAES, W.

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Año: 2017 vol. 97 p. 889 - 896

0025-3154

Among the polychaetes, the family Cirratulidae is one of the most challenging taxonomically because most of the currently used diagnostic characters change during ontogeny. It is therefore necessary to use a combination of characters to make an accurate identification. The present work is the first of a planned revision of the genus Cirratulus from coastal zones of Argentina. The examined material came from the two largest natural history museums of the country, and showed several morphotypes. Some specimens corresponded to the described material, but others are undoubtedly undescribed. Among the previously known Cirratulidae, C. jucundus (Kinberg, 1866) and C. patagonicus (Kinberg, 1866), formerly distributed for Antarctica is now also present in coastal continental areas of Argentina. The new species Cirratulus mianzanii sp. nov. is described from subtidal areas off Peninsula Valdés, Patagonia. This species is distinguished from its congeners by the origin of both tentacular filaments and first pair of branchiae in the junction of peristomium and first chaetiger. Branchiae arise with some distance from notopodium but not at the dorsal midline of the body. Ventral groove present along the body, with a fine dark midline. Capillary chaetae are serrate seen under optical microscope, and the pattern of neuro- and notospines is different from other species of the genus.