Sepia chirotrema Berry 1918

Sepia chirotrema Berry, 1918

Solitosepia hendryae Cotton, 1929:87. [Holotype, SAM D13625, 74 mm SL (78 mm including spine), Rottnest Island, WA (32°00′S, 115°30′E).]

Solitosepia glauerti Cotton, 1929:87. [Holotype, SAM D13628, 49.5 mm SL (51 mm including spine), Rottnest Island, WA (32°00′S, 115°30′E).]

DIAGNOSIS.—Anterior dorsal margin of mantle large, triangular, rostrum-like; ventral margin broadly emarginate without distinct lateral angle. Head with group of 3 conspicuous tubercles on each side between eye and nuchal cartilage, 3 smaller tubercles in arcuate line in front of cartilage. Swimming membrane on tentacular club strong, reaching beyond base of club for short distance. Protective membranes fused at base of club, attached to tentacular stem by short membrane, dorsal protective membrane thick and wide, separated from swimming membrane by deep cleft and perforated by 3 large openings, each situated opposite 1 of 3 large tentacular suckers. Three very large suckers occupy main part of club, median sucker largest, distal sucker slightly smaller, and proximal sucker smaller still, each with long slender stalk attaching sucker to bottom of deep pit; pits separated by transverse membranes bearing 1 small sucker on dorsal side and 2 smaller suckers on ventral side; distal club with 40–50 small, quadriserial suckers (Figure 5a). Left arm IV hectocotylized, distal end attenuated, narrow, and compressed laterally, bearing microscopic suckers.

Sepion sexually dimorphic, wider in males (Figure 5b,c) than in females of same size. Anterior end of male sepion acuminate, posterior end broadly rounded. Dorsal surface granulose, with very distinct, well-defined median rib and 2 less-developed lateral ribs separated from median rib on either side by flat surface about as wide as ribs. Ventral surface flat, with shallow median sulcus along entire length. Striae convex in posterior striated zone, weakly angular, reversed V-shaped near last loculus. Inner cone well developed, lateral limbs reflected and fused with outer cone. Spine strong, rounded, without keel, straight and directed upward; base of spine thickened, forming thick collar in large sepions, separated from spine by circular, radially striated groove; dorsal surface of sepion and spine separated by deep cleft.

ORIGINAL REFERENCE.—Berry, 1918:268, pl. 74: figs. 3–9, pls. 75–77.

TYPE LOCALITY.—Investigator Strait area (35°25′S, 137°22′E), south of Kangaroo Island, SA (35°50′S, 137°15′E), F.I.S. Endeavour sta E2459.

TYPE.—Type missing from Australian Museum. According to Berry (1918), holotype (by original designation) male, 183.0 mm ML.

GEOGRAPHICAL DISTRIBUTION.—Southern Australia from Investigator Strait (35°25′S, 137°22′E) to Dirk Hartog Island, WA (25°45′S, 113°03′E), at depths of 120–210 m.