Medium to large-sized adults up to 120 mm and 1,330 g total weight.
Broad saccular mantle with muscular wall;
two thick cartilaginous stylets (0.2 mm diameter, 18.8 mm long, in a male of 78 mm ML).
Pallial aperture of moderate width (PAI 42–54).
Head wide (HWI 37–48).
Eyes moderately prominent
Funnel tubular ,
Well defined W-shaped funnel organ;
lateral limbs longer;
all four limbs of equal width .
Arms thick (AWI 9–18), relatively short
Third right arm of males hectocotylized, shorter than opposite one , bearing 96–142
suckers. Well defined spermatophoric groove along hectocotylized arm ends at base of relatively long calamus Small ligula.
Total number of suckers on the normal arms 220 to 238.
Normal sucker diameter moderate.
Mature males with 2–4 enlarged suckers at the 8th or 9th row on arms II and III
Web moderately deep, shallower between dorsal arms; deeper between ventral arms
(most common web formulae C . D . B . E . A and D .
C . B . E . A).
I have quoted the external, non-invasive observations. The pdf gives additional biological detail
MORPHOLOGICAL AND GENETIC DESCRIPTION OF OCTOPUS INSULARIS, A NEW CRYPTIC SPECIES IN THE OCTOPUS VULGARIS COMPLEX (CEPHALOPODA: OCTOPODIDAE) FROM THE TROPICAL SOUTHWESTERN ATLANTIC T. S. LEITE1, M. HAIMOVICI1, W. MOLINA2 AND K. WARNKE3 2006