Morphology and morphometry of Doryteuthis plei (Cephalopoda: Loliginidae) statoliths from the northern shelf off São Paulo, southeastern Brazil

Abstract

This study aims to describe and evaluate statoliths of Doryteuthis plei from the northern shelf off São Paulo (23° S), to provide details useful for taxonomic identification, sexual differentiation and estimation of individual size from statolith dimensions. A total of 390 statolith pairs were analysed and their morphology and morphometry were described according to growth and maturity stage. There was a tendency for the extremity of the rostrum and the domes to narrow with growth. A morphological comparison with the statoliths of the congeneric Doryteuthis sanpaulensis was also undertaken. No obvious gross morphological difference among statoliths between sexes was found. A logarithmic model provided the best fit of the relationship between statolith length and mantle length, which can be useful to estimate the squid’s length. Power function equations indicating the allometric relationships are also shown, allowing comparison with other squid populations elsewhere.