Morphological and genetic description of Octopus insularis, a new cryptic species in the Octopus vulgaris complex (Cephalopoda: Octopodidae) from the tropical southwestern Atlantic

A medium-sized Octopus species is described based on material collected in shallow equatorial waters around the oceanic islands of Fernando de Noronha Archipelago, Rocas Atoll, St Peter and St Paul Archipelago and the mainland of northeastern Brazil. The new species, Octopus insularis, is described morphologically, and also characterized by the large mitochondrial subunit ribosomal RNA gene (mt 16S rDNA). The new species has relatively short and stout arms, rugose reddish brown skin in preserved specimens, 8 to 11 gill lamellae on the outer demibranchs, small ligula, characteristic symmetrical radula, spermatophore and beak, small eggs and high fecundity (213,000 oocytes under 1.5 mm diameter). The habitats and skin patterns of living animals are briefly described. The new species differs both morphologically and genetically from Octopus vulgaris in the Mediterranean, Venezuela and southern Brazil.