Mantle robust, slightly flattened dorsoventrally. It can be broad or slender; oval, oblong or nearly circular in outline. The anterior of dorsal mantle margin projected forward, not fused with head. Fins narrow which located dorsolaterally on mantle, approximately equal to mantle length; posterior fin lobes free, not connected to each other. Head is robust and slightly narrower than mantle. Eyes are prominent, which covered by a transparent membrane and a conspicuous secondary fold on the eyelid. Mouth surrounded by 10 appendages (8 arms and 2 tentacles). The cuttlefish arms consist of 2 to 4 suckers in transverse rows. Tentacular clubs consists of four or more suckers in transverse rows and tentacles retractile into pockets on the ventrolateral sides of the head between arms III and IV. Internal calcareous cuttlebone was located dorsally in the mantle which underneath the skin and cuttlebone length usually equal to the mantle length. The cuttlebone shape are ranges from lanceolate to oval or diamond-shaped whereas dorsal side is calcareous plate and ventral side finely laminate. Buccal membrane present, with or without suckers; each radula tooth unicuspid (with a single projection).
Genus: Sepia Linnaeus, 1758
Species: Sepia lycidas Gray, 1849
Mantle shape is elliptical. Dorsal anterior margin is triangular and acute, while ventral mantle margin is emarginate. Fins end posteriorly in lobes, with only a small slit between them. Arm suckers tetraserial. Hectocotylus present on left ventral arm at 6 rows of normal size suckers proximally and 4 rows of reduced suckers distally. Tentacular club with 8 suckers in transverse rows and all club suckers are similar with small size. Swimming keel of club shorter than carpus, extends from proximal 1/3 to distal tip of club. Dorsal and ventral protective membranes not joined at base of club, extend as membranous ridges along entire stalk. Cuttlebone outline oblong with shape of bone bluntly rounded anteriorly and posteriorly. Dorsal surface is evenly convex and dorsal median rib is absent. Spine short and pointed. Sulcus deep and wide. Anterior striae are inverted V-shape. Inner cone limbs are thickened posteriorly, broaden into a rounded ridge, while, outer cone calcified; narrow anteriorly, broadens posteriorly. Colour is reddish brown or purple. Dorsal mantle has scattered ocellate patches and narrow, irregular, light-color, transverse stripes (pattern more prominent in males than females). Wide stripe adjacent to fins.
Sepia subaculeata Sasaki, 1914
Sepia lycidas Gray, 1849- [Carpenter and Niem (1998): 745; Jereb and Roper (2005): 95-96]
Indo-Pacific: southwestern Japan, south of Boso Peninsula from southern Honshu and Chingtao, Korea, to East China Sea, Taiwan Province of China and South China Sea, Philippine Sea, Vietnam and Borneo.
Sepia lycidas has been assessed as Data Deficient in the IUCN Red List as data on the impact of fishing are not available. This species is commercially important in several Asian countries, particularly towards the northern boundary of the Indo-West Pacific. Although the species has an extensive geographic range extending southwards from the Yellow Sea to Indonesian Seas, it is fished very hard across much of its range and more data are required to assess the impacts of this.