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

Anguilla australis ?australis (Text-fig. 3, D, E, F), glass-eel

Anguilla australis ?australis (Text-fig. 3, D, E, F), glass-eel.

Material Examined. Two specimens, 52.5mm and 57.9mm total lengths, Aust. Mus. regd. no. IB.5289; rock-pool, Forty Baskets Beach, Sydney; 12/6/61.

Description. Measurements in mm: total length 57.9 (52.5), head 6.0 (6.0), snout 1.4 (1.1), eye 0.6 (0.7), interorbital 0.3 (0.3), upper jaw 1.4 (1.7), postorbital 4.3 (4.1), pectoral 1.1 (1.2), preanal 20.0 (−), predorsal 19.8 (−), depth just before eye 1.0 (0.8), depth at pectoral origin 1.8 (1.8), depth at midpoint between pectoral and vent 1.5 (1.5), depth at anal origin 1.4 (1.7). Branchiostegal rays 12 (12), pectoral rays 19 (18), dorsal rays before level of vent 9 (8), total rays ca. 193 (211), anal rays ca. 186 (203), caudal rays 2 + 2 + 2 + 2 (2 + 2 + 3 + 2). Teeth 5 + 2 over 10 + 2 and (5) over (7). Myomeres 39 + 74 = 113 (110). a–d = 2 (2).

Body greatly elongate, cylindrical, compressed only near tip of caudal region, tapering only at snout and at tip of caudal. Head long, about one-tenth of total length, slightly swollen in front of pectoral but otherwise little differentiated from trunk; snout rounded, less than one-quarter of head length with anterior nostril far forward on tip of snout, posterior nostril a little in advance of eye; eye less than twice in snout or about seven times in postorbital, circular; gape oblique, extending to just behind forward margin of eye, lower jaw projecting for a distance equal to length of pupil. Teeth bluntly conical, short, sparse, uniserial, unlike those of the leptocephali; distributed as follows: on the maxilla five small teeth are followed by two larger ones posteriorly, while on the dentary there are ten small teeth anteriorly and two larger ones posteriorly. Pectoral fin about equal to snout, oval. Dorsal fin low, originating only a short distance in advance of the anal; anal fin also low, caudal fin well differentiated from the tips of the dorsal and anal fins.

Colour in preservative restricted to a few large melanophores on the lateral surface of the head, a continuous series of deeply-placed, expanded melanophores on the spinal cord beginning at the level of the pectoral fin through to the tip of the caudal region, a scattering of pigment laterally on the tip of the caudal region and on the caudal fin as well as a pigmented chorioid.

Remarks. The specimens described here are transitional elvers between Stage V and Stage VI of Strubberg (1913, p. 4); that is, they have surface pigment on page 12 the caudal, deep pigment on the caudal region of the spinal cord and neck, but the body is cylindrical. The two specimens, having two myomeres between the levels of dorsal and anal origins are short-finned and with a high number of myomeres, 110 and 113, can be referred to A. australis. They were collected at Sydney, New South Wales, and therefore fall well within the geographical range known for the Australian subspecies, A. australis australis.