FAO Species Identification Guide for Fishery Purposes Western

Sepiidae 751
Sepia rex (Iredale, 1926)
Frequent synonyms / misidentifications:
Decorisepia rex Iredale, 1926; D.
cottlesloensis Cotton, 1929; D. jaenschi
Cotton, 1931 / Sepia madokai Adam, 1939.
FAO names: En - King cuttlefish.
Diagnostic characters: Arms in both sexes
with tetraserial suckers. Left ventral arm (IV)
of males hectocotylized: 6 to 8 rows of
normal suckers proximally, followed by 9
or 10 rows of reduced suckers, then rest
normal to arm tip; reduction marked, 2
dorsal and 2 ventral series widely spaced;
suckers equal sized across series; oral
surface wide, fleshy, with transversely
grooved ridges and shallow median furrow.
Tentacular club sucker-bearing face
flattened; with 10 to 12 similar-sized,
minute suckers in transverse rows;
swimming keel extends well beyond club;
dorsal and ventral protective membranes
not fused at base of club, joined to stalk at
base of club and terminating at posterior end
of sucker-bearing face; dorsal protective
membrane forming deep cleft at junction
with stalk. Cuttlebone outline oblong,
narrowed anteriorly, tending to diamondshaped,
maximum width in middle of
cuttlebone; dorsal surface pinkish; median
dorsal view
ventral view
cuttlebone
(after Iredale, 1926)
rib present, distinct; spine without keel(s); ventral sulcus extending entire length of cuttlebone, shallow,
narrow; anterior striae inverted U-shape; inner cone limbs of uniform width, thickened posteriorly
forming a rounded ridge; outer cone narrow anteriorly, broadens posteriorly. Colour: pale pinkish purple.
Size: Maximum mantle length 120 mm.
Habitat, biology, and fisheries: At depths from 55 to 400 m. Taken as bycatch of prawn and mixed species
trawl fisheries.
Distribution: Southern Australia.
Remarks: Sepia rex has been
confused with S. madokai. It
differs in having all reduced
suckers of the hectocotylus
similar in size, while in S.
madokai, the 2 dorsal series
are much smaller than the 2
ventral series. The club
suckers in S. madokai (8
suckers in transverse rows),
are fewer than those (10 to
12) seen in S. rex. The
cuttlebone in this species has
distinct median ribs and the
inner cone limbs are of
uniform width, while in S.
madokai it has faint median
ribs, and the inner cone limbs
broaden posteriorly. S. rex
may be synonymous with S.
hedleyi Berry, 1918.