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Zoology Publications from Victoria University of Wellington—Nos. 33 and 34

L. Anguilla australis ?schmidti (Text-fig. 2, A, B, C)

page 9

L. Anguilla australis ?schmidti (Text-fig. 2, A, B, C)

Material Examined. One specimen, 24.6mm total length; IFO St. 56–4–2; 14° 37′ S., 170° 03′ E.; 26/9/56 (2122 hrs) ; horizontal tow in 10m; 0.5m net, No. 2 mesh. One specimen, 47.6mm t.1.; IFO St. P 60–2–1; 22° 38′ S, 168° 20′ E; 11/4/60 (1953 hrs); hor. tow in 50m; 0.5m net, No. 2 mesh.

Description. Measurements in mm: total length 47.6 (24.6), head 4.3 (2.8), snout 1.0 (1.2), eye 0.7 (0.6), upper jaw 1.6 (1.2), postorbital 2.4 (1.2), pectoral 1.1 (0.5), preanal 29.6 (19.2), predorsal 27.0 (18.2), depth just before eye 1.8 (1.2), depth at pectoral origin 3.4 (2.0), depth at midpoint between pectoral and vent 8.5 (4.2), depth at anal origin 9.4 (4.1). Branchiostegal rays 12 (−), pectoral rays 17 (−), dorsal rays before level of vent 26 (−), total rays 194 (−), 1st dorsal ray at level of myomere 58; anal rays 187 (−), caudal rays 2 + 2 + 2 + 2. Teeth none and 1 + V + 3 over 1 + 1 + II + 3. Myomeres 62 + 54 = 116 (112). a–d = 3 (2). Vertical blood-vessels at myomeres 17, 41, 48 (17, ? 48). Anterior margin of gall-bladder at myomere 27 in one specimen, obscured in the larger specimen.

Body not excessively elongate, much compressed except along the head but relatively deep with the maximum depth contained about five times in total length; tapering about equally in front of and behind the midpoint of the body. Head short, about one-tenth of total, slightly indented at the throat: snout about one-fourth of head, rounded, with a slightly convex dorsal profile and both nostrils well separated; eye contained 1.3 times in snout, oval, with the greatest diameter vertical; cleft of mouth oblique, extending to level of middle of pupil; teeth absent in the larger specimen, but eight small cavities remain in the lower jaw. Branchiostegal rays well developed and curving across the space in front of pectoral. Pectoral fin just less than snout and eye combined, rounded, base of fin fleshy. Dorsal fin low, with the radials visible throughout as well as most of the rays. Anal fin conspicuously higher than the dorsal. Caudal fin not greatly differentiated from the dorsal and anal.

Colour translucent with pigment restricted to the chorioid of the eye.

Remarks. These two leptocephali are short-finned, having the difference between the dorsal and anal origins equal to three myomeres. The two species of short-finned eels present in the south-west Pacific are A. australis with 108–116 vertebrae and A. obscura with 101–107 vertebrae. The two larvae have 112 and 116 myomeres and are therefore referred to A. australis. Two subspecies of A. australis have been recognised: A. australis australis Richardson in New South Wales, Victoria, Tasmania and Lord Howe Island and A. australis schmidti Phillipps from New Zealand and outlying islands, Norfolk Island, New Caledonia, Fiji, and possibly Tahiti. The larger specimen of these two larvae, almost at metamorphosis, was taken very close to New Caledonia and is probably A. australis schmidti. The smaller specimen was taken far from the area known for the adult of the Australian subspecies and is also tentatively referred to A. australis schmidti.