External ultrastructure of Manayunkia speciosa Leidy, 1858 (Sabellidae, Fabriciinae) from Uruguay River, Argentina

PAOLA, ANALÍA C.; ARMENDÁRIZ, L.C; RODRIGUES CAPÍTULO A.

REVISTA MEXICANA DE BIODIVERSIDAD

INST BIOLOGIA

Lugar: México 84: 521-529,; Año: 2013 vol. 84 p. 521 - 529

1870-3453

Abstract. We describe the external ultraestructure of Manayunkia speciosa Leidy, 1858 from specimens collected at the lower Uruguay River, South America by scanning-electron-microscopy. The prostomial tentacular crown has ventral palps and a semicircular lateral lobe with a diagonal ventrolateral outer branch. Tentacle surfaces are ciliated. The faecal groove is observed on peristomium middorsally. The anterior margin of the anterior peristomial ring formed a rectangular lobe, with a ciliated band. Chaetal shape exemplifies the basic type of tapering cylinder. Thoracic notosetae consist in two types: one wider distally, with a smooth handle, and covered on the surface by denticles, and the other are significantly finer at the base and covered by flexible thin structures. These structures were not previously recorded in Sabellidae. Rows of 3 aligned uncini anteriorly projected are found in the thorax. Each uncinus presents a long manubrium which connects with the capitium, extending to a rostrum. The spines of the capitium are almost equal in size. The abdomen present 4 types of neurosetae: one of small size than the other 3. In the abdomen 10-14 uncini form dense dorsal-transverse lines. Each uncinus presents a short manubrium. The capitium is covered with spines of similar size.