Shell phenotypic variation in the Southwestern Atlantic species Olivancillaria carcellesi (Gastropoda: Olividae)

TESO, VALERIA; SIGNORELLI, JAVIER H.; PASTORINO, GUIDO

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Lugar: Londres; Año: 2010 p. 1 - 6

0025-3154

Phenotypic variation on shell size and shape of Olivancillaria carcellesi from four representative localities is confirmed usinggeometric morphometric techniques. This species lives along the entire range of the genus in subtidal soft bottoms from Rio deJaneiro (Brazil) to Punta Pardelas (Chubut, Argentina). Thickness of columellar callus, length and width are the main shelldifferences from specimens collected at several intermediate localities: Cassino (Brazil), La Paloma (Uruguay) and Mar delPlata (Argentina). All forms showed significant differences in shell size except O. carcellesi from La Paloma compared withthose from Mar del Plata. The group with larger specimens was from Cassino. Olivancillaria carcellesi from Punta Pardelas,the southernmost population, was the smaller sized group and showed allometry between size and shape and this is responsiblefor their relatively higher spires. The possible ecological implications of the observed pattern are discussed. It is confirmedthat O. carcellesi although variable, is a clearly defined species.