Sepiola atlantica
<p><em>Sepiola atlantica</em> (Orbigny in Férussac & Orbigny, 1840)</p>
Sepiola atlantica. Concealment takes 20 seconds; siphon blows depression in sand. Tentacles move any stones and brush sand over top. Jan. 2007. North Wales.
Sepiola atlantica. Two coiled captorial tentacles near mouth, and 8 arms. Two rows of colourless transparent suckers on each arm. Mantle pale ventrally. Translucent white exhalent funnel pointing down. June 2008. Connemara, Ireland.
Sepiola atlantica. Two coiled captorial tentacles near mouth, and 8 arms. Lateral fins on down stroke over body, almost invisible. Pale ventrally. Red crustacean protruding from mouth. July 2008. N. Wales.
Sepiola atlantica. Siphon pointed to jet water forwards to propel animal backwards (mantle first). Sand grains on dorsum. Ventral surface coloured as dorsum, but a little paler. June 2009. Connemara, Ireland.
Sepiola atlantica. Hovering with aid of fins and exhalent funnel pointed down. Ventral surface coloured as dorsum. Abrupt change to deep sienna brown startles attacker, and tentacles held up increase apparent size. June 2010. Connemara, Ireland.
Sepiola atlantica. Hovering with aid of fins and translucent white exhalent funnel pointed down. Attached bases of fins do not reach anterior or posterior of mantle. June 2009. Connemara, Ireland.
Sepiola atlantica. Fins move like wings to propel forwards or backwards. Attached bases of fins do not reach anterior or posterior of mantle. June 2009. Connemara, Ireland.
Sepiola atlantica. Mantle cavity open dorsally, except mid part fused to head. Large fins move like wings; translucent except chromatophores basally. Translucent border on lateral arms. Head mainly made of large eye bulges. June 2008. Connemara, Ireland.
Sepiola atlantica
Sublittoral inshore shallows, occasionally stranded in shore pools, to 150 metres. Clean sand or fine shell gravel substrate. Sometimes nektonic; fins move like wings to propel forwards or backwards [2]. Exhalent funnel expels water steadily downwards to hover motionless [3], and strongly forwards to escape backwards (mantle-first) from danger [5]. Often benthic during daytime, lying buried in sand [8] awaiting small crustacea. Concealment takes 20 seconds; exhalent funnel blows depression in sand, blown sand settles on top of sepiole; arms move any stones and brush sand to complete cover.
By expanding or contracting different chromatophores, colour can change dramatically in less than a second to provide camouflage [9] or startle and distract attackers, often with dark sienna [4]. Sometimes discharges viscous sepia to distract predator as it jets away. Small crustacea [6] caught by rapidly uncurled pair of long captorial tentacles. Predators include fish. During mating on seabed, male holds female from below and behind while specialised left dorsal arm, hectocotylus, transfers spermatophores into her mantle cavity (TOL image). Between 30 and 150 eggs deposited on firm surfaces in each of several nocturnal spawning bouts spread over about three weeks. Female dies shortly after spawning. Young about 1.5mm long at hatching. Resemble miniature adults with relatively shorter arms and tentacles.
Rossia macrosoma (della Chiaje, 1829) (MSIP)
- Short plump ovoid mantle, total length body and tentacles to 180mm.
- Eight arms and two captorial tentacles kept coiled by mouth.
- Two rows of suckers on each arm, 4 or more rows distally.
- About ten rows of small suckers on captorial tentacle club.
- Bases of short, fleshy, rounded, lateral fins do not reach anterior or posterior of mantle.
- Mantle cavity open round entire perimeter with pronounced lip, without any fusion to head.
Sepietta oweniana d’Orbigny 1839 (MSIP)
- Stout ovoid mantle, total length body and tentacles to 110mm.
- Eight arms and two captorial tentacles.
- Dorsal pair of arms joined by membrane at base, intervening cleft obviously shorter than between other arms.
- Left dorsal arm, hectocotylus, greatly widened on male.
- About thirty rows of very small suckers on captorial tentacle club.
- Bases of large thin lateral fins do not reach anterior or posterior of mantle.
- Mantle cavity open ventrally and dorsally except for mid section of dorsal mantle edge fused to head.
Sepiola atlantica
- Short plump ovoid mantle, total length body and tentacles to 45mm.
- Eight arms, and two captorial tentacles kept coiled by mouth [6].
- Two rows of suckers on each arm, 4-8 rows distally on dorsal arms.
- Bases of large, thin, translucent, lateral fins do not reach anterior or posterior of mantle [2].
- Mantle cavity open ventrally and dorsally except for mid section of dorsal mantle edge fused to head [1].
Current taxonomy: World Register of Marine Species (WoRMS)
Gosse, P.H. 1856. The aquarium. 2nd ed. London. pp.58-66(Archive)
Groenenberg, R.S.J., Goud, J., Heij A.de & Gittenberger,E. 2009 Molecular phylogeny of North Sea Sepiolinae (Cephalopoda: Sepiolidae) reveals an overlooked Sepiola species. J. Mollus. Stud. 75(4): 361-369
Hardy, A., 1970. The open sea: Its natural history. Part one: The world of plankton.
Marine life information network (MARLIN)
Marine species identification portal (MSIP)
Morton, J.E., 1967. Molluscs. London.
Tree of Life (TOL)
Yau, C. & Boyle, P.R., 1996. Ecology of Sepiola atlantica (Mollusca : Cephalopoda) in the shallow sublittoral zone. J. mar. biol. Ass. U.K. 76, 733-748. (pdf).
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