Analysis of beak morphometry of the horned octopus Eledone cirrhosa, Lamarck 1798 (Cephalopoda: Octopoda), in the south−eastern Adriatic Sea

Abstract

      This paper presents the first information on Eledone cirrhosa beak morphometry and pigmentation in the Adriatic Sea. The analysis was performed on beaks from 136 female and 82 male specimens caught by demersal trawls in the south–eastern Adriatic. Male–to–female ratio was 0.6:1. Males had larger beaks relative to the mantle length than females, but the difference was not statistically significant. Beak growth was allometrically negative in relation to mantle length and body weight. The situation was similar regarding beak growth in relation to upper and lower mandible hood length, where only the upper rostral length and lower jaw width values in females showed b–values higher than 1. Four stages of pigmentation were identified in upper and lower beaks, with a significant degree of overlapping in relation to mantle length.