Bigfin reef squid
Shape variable from short and stout to long and slender. Fins terminal or marginal, but always united posteriorly; funnel-locking apparatus a simple, straight groove. Eyes covered with transparent skin (corneal membrane); buccal connectives attached to ventral borders of fourth arms; 7 bucca1 lappets supplied with small suckers (except in Lolliguncula and Alloteuthis); 8 arms and 2 tentacles around mouth; 2 rows of suckers on arms and 4 rows on tentacular clubs, hooks never present. Usually the left arm of the IV (ventral) pair is hectocotylized in males (used to transfer sperm packets from the male to the female); the structure of the modified portion (hectocotylus) of the arm is useful in most species as a diagnostic character (often, the suckers on the hectocotylus are reduced in size or number, or modified into fleshy papillae or flaps (lamellae), or they disappear altogether. Colour: usually reddish-brown, darker dorsally, but quite variable depending on the behavioural situation.
Genus: Sepioteuthis Blainville, 1824
Species: Sepioteuthis lessoniana Férussac, 1831
Mantle long, robust, its width about 40% of length. Fins very large, length over 90% mantle length, width up to 75% mantle length; greatest width occurs posterior to the midpoint of the fins. Tentacular clubs long, expanded; median manus suckers enlarged; rings with 14 to 23 sharp conical teeth. Arm sucker rings with 18 to 29 long sharp, regularly spaced, conical teeth around entire margin; tentacles long, robust; left arm IV hectocotylized along distal 25 to 30%. Colour: dark to light brown to pale translucent; iridescent pale transverse bars or spots are present dorsally in all colour phases and are distinctive of this species. Size: Maximum dorsal mantle length 422 mm in males, smaller in females; commonly 200 to 300 mm mantle length.
Sepioteuthis hemprichii Ehrenberg, 1831; Sepioteuthis guinensis Quoy & Gaimard, 1832; Sepioteuthis lunulata Quoy & Gaimard, 1832; Sepioteuthis mauritiana Quoy & Gaimard, 1832; Sepioteuthis doreiensis Quoy [in Férussac & d Orbigny] 1835; Sepioteuthis sinensis d Orbigny [in Férussac & d Orbigny] 1848; Sepioteuthis arctipinnis Gould, 1852; Sepioteuthis neoguinaica Pfeffer, 1884; Sepioteuthis brevis Owen, 1881; Sepioteuthis indica Goodrich, 1896; Sepioteuthis sieboldi Joubin, 1898; Sepioteuthis malayana Wülker, 1913; Sepioteuthis krempfi Robson, 1928
Sepioteuthis lessoniana Férussac [in Lesson], 1831- [Carpenter and Niem (1998): 778; Jereb and Roper (2010): 95-97]
Widespread in the Indo-Pacific: Red Sea eastward to the Hawaiian Islands, northern Australia to central Japan.
This taxon has not yet been assessed for the IUCN Red List.