Amphioctopus robsoni (Adam 1941)

Octopus robsoni Adam, 1941

DIAGNOSIS.—Animals small to medium-sized (28–60 mm ML). Mantle round to oval (MWI 67.5–90.0); neck slightly constricted; head narrow (HWI 36.5–59.0); eyes small, deeply set. Funnel of average size, funnel organ W-shaped, inner and outer limbs subequal in length. Arms moderate in length (ALI 71–77), arm formula variable, arms I typically shortest; arms slender, tapering to fusiform tips. Suckers slightly elevated, of average size (SIn 5.7–10.6); especially enlarged suckers absent in males and females. Right arm III of males hectocotylized; ligula moderate in size (LLI 15.6–23.7), tapering to point, with central groove and weak transverse laminae; calamus small (CLI 15.7). Web moderate to deep (WDI 20–30.5), web formula variable but with sector A consistently shallowest and all others probably subequal. Gill lamellae 8–10. Radula with A2–3 seriation of rachidian. Surfaces of mantle, head, and arms granulated, mantle with larger papillae and up to 6 supraocular papillae in some specimens. Large ocellus, consisting of dark spot surrounded by dark ring, on each side of head between eyes and margin of web. General color in preservation (alcohol) beige with brown maculations on head and mantle; arms with brown band down ventral edges along suckers.

ORIGINAL DESCRIPTION.—Adam, 1941:1.

TYPE LOCALITY.—Gulf of Suez.

TYPES.—Syntypes: MNHN 5-3-1038–44, 5 females, 7 males, in alcohol, good condition.

DISTRIBUTION.—Positively known from the type locality only.