Pleurobranchaea inconspicua Bergh, 1897 (Opisthobranchia: Pleurobranchidae): Redescription and distribution of an amphiatlantic species from the Colombian Caribbean and Argentina

MUNIAIN, C.; ARDILA, N.; CERVERA, J. L.

Bonn, Germany

Workshop; 2nd International Opisthobranch Workshop; 2006

Zoologisches Forschungsmuseum Alexander Koening

Pleurobranchaea inconspicua was described by Bergh (1897) from an individual collected in Sergipe, Brazil (10º 54´ S, 37º 7´ W). P. hedgpethi (Port Aransas, Texas), P. hamva (Ilhabela, Brasil), and P. gela (West Africa) are considered synonym species. P. inconspicua has a wide geographical distribution range (35º N to 40º S; 97º N to 42º W), being San José Gulf (42º 14´ S; 64º 27´ W, Argentina) the southernmost location for the species. In this work the species P. inconspicua is redescribed from live specimens from the South Atlantic (Argentina), the Caribbean (Colombia), and from material preserved in the collection of the Argentine Museum of Natural Sciences “Bernardino Rivadavia”. The geographical distribution of the species of the genus Pleurobranchaea is analyzed; especially those species with possible amphiatlantic distribution and the most outstanding features of the species of the genus are compared. Individuals were collected from shallow waters in the intertidal zone to 150 m in depth. The base color is pale cream, with a dense dark brown reticulate along the dorsal region, being lighter and less obvious in the foot region and absent in the rinophores. The latter exhibit an almost black posterior edge and are well developed. Bright white spots are scattered all over the mantle surface. A conspicuous metapodial gland and a tail-spur black were observed dorsally. The length recorded in live specimens ranged between 13-60 mm, including the posterior end of the foot. The radula and jaw plates were studied with scanning electron microscopy, which agreed morphologically with previous descriptions of the species.