Viet Nam cuttlefish
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 vietnamica Khromov, 1987
Mantle is broad, oval and dorsoventrally compressed. Fins wide, anterior origin almost at mantle margin, rounded posteriorly. Hectocotylus present on left ventral arm. Suckers of hectocotylus in 2 dorsal series are smaller than those in 2 ventral series. Dorsal suckers partially covered by wide protective membrane. Sucker-bearing surface flattened, with 5 suckers in transverse rows. Suckers differ slightly in size whereas 4 or 5 suckers enlarged in second ventral row, with suckers decreasing in size from this row to margins. Swimming keel of club extends slightly beyond carpus. Dorsal and ventral protective membranes not joined at base of club. Shape of cuttlebone is lanceolate. Bone is widest in anterior 1/3 where bone bluntly rounded anteriorly and acute posteriorly. Lateral ribs absent. Spine is long, pointed and straight. Anterior striae is m-shape. Limbs of Inner cone are uniform in width and narrow V-shape posteriorly, slightly raised into rounded posterior ridge. Outer cone limbs are expanded posteriorly into 2 short �wings�, directed ventrally, to form a recurved cup-like structure. Color of the species is dark brown. Head with 2 small and crescent-shaped of orange spots near dorsal of mantle margin and above eyes. Arms I to III have spots on aboral surface as for mantle.
Sepia vietnamica Khromov, 1987- [Jereb and Roper (2005): 125-126]
Indo-Pacific: northwestern South China Sea, off Viet Nam and Taiwan Province of China
Sepia vietnamica has been assessed as Data Deficient as it is probably taken in fisheries throughout its range but no information is available as to how great the fishing pressure might be. Very little is known about this species generally and further research is recommended.