Some Additional New Zealand Cephalopods from Cook Strait
Family Enoploteuthidae — Genus Enoploteuthis d'Orbigny, 1839 — Enoploteuthis neozelanica n.sp. Figs. 11–13
Genus Enoploteuthis d'Orbigny, 1839
Enoploteuthis neozelanica n.sp. Figs. 11–13.
Animal small, mantle narrowly conical; widest anteriorly, thence tapering regularly to a rather blunt posterior point. Anterior edge of mantle drawn out into a wide angular extension dorsally, broadly emarginate ventrally between two obtuse points marking the position of the funnel locking apparatus. Fins very large in proportion, triangular, the width across both fins only slightly less than the dorsal mantle length, outer angles sharply rounded, anterior margins lobed, posterior extremity fusing with the integument of the mantle very gradually some distance in front of the posterior extremity of the body.
Head squarish in cross section, a little longer than wide, somewhat excavated ventrally, a single rather delicate lamella on either side in the nuchal area. Eyes of moderate size, the lid opening with a well-developed anterior sinus.
Funnel large, broad, bluntly swollen at the apex. Mantle locking apparatus consisting of a simple, broad and shallow cartilaginous pit on either side of the base of the funnel and a corresponding simple ridge on the mantle.
Arms rather thick-set, moderately long. The order of length is 4, 2 = 3, 1; the ventral pair distinctly the longest, and the dorsal pair distinctly the shortest, the second and third pairs subequal in length, although the third pair is markedly stouter. First pair of arms with a poorly developed carination; second pair of sessile arms with a weak carination developed over the distal third; third pair of page 7arms with a well developed membranous keel extending over the distal two-thirds of the arm; fourth pair of arms with the mantle integument extending as a very narrow fold along the outer ventral angles. All arms bare in proximal area but becoming armed with two rows of alternately placed, moderately sized hooks which continue almost to the distal extremities. Extreme tips of arms with several rows of close-packed minute suckers. About 11 pairs of hooks on the first pair of sessile arms, 8 on the second, 10 on the third and 15 on the fourth pair. Hook-bearing faces of all arms bordered by well developed trabeculate swimming membranes.
The right hand fourth sessile arm hectocotylized, the structure of this arm being exactly as described and figured for galaxias by Berry (1918. p. 213, Pl. 60, Fig. 5).
Right tentacle missing, left tentacle stout, considerably longer than the dorsal mantle length, stalks somewhat flattened producing a rather rectangular cross-section. Club (Fig. 13) narrowing from carpus, outer face with a short but prominent carinate membrane situated just distal to the carpal fixing apparatus. Club gradually tapering from the carpus. Fixing apparatus compact, occupying a well defined oval section on the inner face of the carpus. consisting of 5 small suckers and 4 small pads.
Club armed with two rows of alternately placed hooks, those on the ventral edge much larger than the dorsal series, four hooks in each series, the two proximal hooks in the ventral series the largest, the second and third subequal and the largest in the dorsal series. A minute sucker associated with the base of each hook in the dorsal series. Distal extremity of dub with about 9 rows of minute, close-packed suckers, four suckers in a row across the club. A small comparatively wide membrane borders the dorsal, distal half of the club.
Buccal membrane eight-pointed, the points supported by colourless raised stiffening rods, membrane very dark in colour, prominent.
Photophores very numerous arranged as follows:—
Mantle: A very few, sparsely scattered photophores on the anterior dorsal surface of the mantle and a few in the mid dorsal line between the fins. No photophores on the fins. On the ventral surface of the mantle photophores of two sizes are closely, more or less equally spaced, but do not form any discernible pattern. One kind are large, spherical and deep-seated, the others much smaller, more frequent and dot-like, confined to the surface of the integument.
Funnel: Three irregular rows of the larger photophores on each side of the mid-line leaving a wide band bare of photophores down the centre. Other larger photophores are scattered rather irregularly on the lateral surfaces of the funnel. The smaller dot-like photophores are also present.
Head and Arms: Only the larger type of photophores occur. On the dorsal surface of the head there are a few irregularly disposed photophores, with more on the arms. Ventrally there is one row of closely spaced photophores right down the inner ventral face of the fourth pair of arms, continuing down the head for its full extent as two parallel rows of photophores. A less regular row of more scattered photophores extends down the outer ventral face of the fourth pair of arms to continue down the head, at first parallel to the inner rows but diverging posteriorly to end rather irregularly near the postero-lateral ventral angle of the head. A rather irregular, sparser row of photophores runs down the middle of the third pair of sessile arms to continue on to the lateral surface of the head. A ring of close spaced photophores around the whole border of the eyelid, close-spaced and more numerous ventrally. Four rather larger photophores are situated on the ventral page 8periphery of the eyeball. A large, elongate photophore on the tip of each ventral arm.
Holotype (M.10378) in Dominion Museum.
Locality: Off Kahu Rocks, east coast of Wellington, taken from a commercial fish trawl which had been working in 50 fathoms. F. Abernethy, October, 1956.
There are three other described species of Enoploteuthis, E. leptura Leach from the Atlantic, E. chuni Ishikawa from Japan and E. galaxias Berry from eastern Australia. The new species has the form of the young specimen figured by Chun (1910, Taf. 11, figs. 5, 6) of leptura Leach. It differs from this stage of leptura in having a subsidiary row of hooks on the tentacle clubs, a proportionately much smaller area of small suckers distally on the tentacle club and an irregular arrangement of photophores on the ventral surface of the mantle. The arrangement of the photophores and the details of the tentacle clubs also distinguish it from chuni and galaxias. From galaxias it differs in having fewer hooks on the tentacle club and fewer photophores on the ventral surface of the eyeball.
From the shape and general proportions it appears that E. neozelanica n.sp. is only half grown. Even at this stage the differences cited above render the species distinctive and the proportionate differences between body and fins have not been stressed as they may well change with development.
|Dorsal mantle length||37 mm|
|Ventral mantle length||33 mm|
|Length to base of dorsal arms||50 mm|
|Extreme length of fins||28 mm|
|Width of single fin||15 mm|
|Width across fins||34 mm|
|Diameter of body||14 mm|
|Length of head||12 mm|
|Width across eyes||10 mm|
|Length of funnel (median)||8 mm|
|Length of left tentacle||45 mm|
|Length of left tentacle club||8 mm|