Double Hectocotylization in Hubb's Octopus, Octopus hubbsorum (Cephalopoda: Octopodidae)

Double hectocotylization in octopods has only been reported for some individuals of a few species, often affecting arms of the same pair. We herein report several cases of non-bilateral double hectocotylization in a single species collected in different locations of the Mexican Pacific coast. The octopuses were identified by morphological and molecular criteria as Hubb's octopus, Octopus hubbsorum. The “regular” and “accessory” hectocotyli were examined by histological analysis; in the latter, the calamus was present and no ligula was detected. Double hectocotylization can be an intrinsic character of the species.