Abdopus horridus (d'Orbigny 1826)

Octopus horridus Orbigny, 1826

DIAGNOSIS.—Animals small to medium-sized (to ~30 mm ML). Mantle rounded medially, pointed apically (MWI 58–88.7); neck region relatively long and strongly constricted; head moderate in width (HWI 50–80); eyes strongly projecting. Funnel tapered, narrow at aperture, funnel organ W-shaped, outer limbs about 20% shorter than medial limbs. Arms moderate to long (ALI 77–84.5), arm formula variable, typically IV = III = II > I; arms tapering to slender tips. Suckers moderate in size, larger in males (SIn 11.8–16.5) than in females (SIn 9.5–13.5), suckers deeply set into arms; in males, 6, 14, and 18 suckers especially enlarged on arms II, III, and IV, respectively, beginning with sucker number 10 or 11, enlarged suckers increase in size from arms II to arms IV (SIe 20.5). Right arm III of male hectocotylized (HALI 302–345), shorter than fellow (FAI 76.6); ligula small (LLI 1.8–4.0), narrow, pointed apically, with shallow groove with weak transverse laminae; calamus large (CLI 33.3), pointed, HASC 90. Web shallow (WDI 9.5–16.5), web sectors subequal but with tendency for sector A to be shallowest. Gill lamellae 5 to 6. Male with simple, moderately sized penis (PLI 24.1) with short, rounded diverticulum roughly in line with long axis of penis. Radula with A3 seriation of the rachidian; rachidian simple with single denticle on either side of median cusp. Surfaces of mantle, head, and arms with numerous unbranched, warty papillae, single papillae typically present in center of light-colored patches; general skin texture warty. Color in life reddish magenta-purple reticulated with large, circular to oval white spots; when alarmed, ground color deepens and lighter spots become light reddish purple. Color in preservation (alcohol) tan to brown with dark splotches on head and mantle and reticulated pattern of brown splotches on dark background down dorsal and aboral surfaces of arms; ventral surfaces of mantle and arms lighter.

ORIGINAL DESCRIPTION.—Orbigny, 1826:144.

TYPE LOCALITY.—Red Sea, Egyptian coast.

TYPES.—Not designated. The type figure is that by Savigny, 1817: Céphalopodes, pl. 1: fig. 2 (see also “Discussion”).

DISTRIBUTION.—Red Sea, Indian Ocean, western and central Pacific Ocean? (see “Discussion”).