Zoology Publications from Victoria University of Wellington—Nos. 33 and 34
L. Anguilla marmorata and L. Anguilla reinhardti
L. Anguilla marmorata and L. Anguilla reinhardti
Material Examined. One specimen, 27.3mm total length; IFO St. Ep 27b(l) ; 17° 13′ S., 162° 30′ E.; 28/9/60 (0205 hrs); 2 oblique tows in 0–300m; 0.5m net, No. 2 mesh. One specimen, 27.6mm t.1.; IFO St. Ep 9b(l); 17° 40′ S., 157° 40′ E.; 17/9/60 (0206 hrs); 2 obl. tows in 0–300m. One specimen, 37.3mm t.1.; IFO St. S 6; 11° 51′ S., 159° 13′ E.; 11/6/62; 5ft midwater trawl (Isaacs-Kidd) ; ca. 95m. One specimen, 39.2mm t.1.; IFO St. P Bs 16; 12° 59′ S, 165° 42′ E; 13/11/58 (0311 hrs); 2 obl. tows in 0–300 m; 0.5m net, No. 2 mesh. One specimen, 41.4mm t.1.; IFO St. D 10; 14° 50′ S., 157° 52.5′ E.; 16/5/60 (2003 hrs) ; 2 obl. tows in 0–300m; 0.5m net, No. 2 mesh. One specimen, 43.6mm t.1.; IFO St. Ep 19b(1); 10° 24′ S, 160° 30′ E.; 24/09/60 (0204 hrs); 2 obl. tows in 0–300m; 0.5m net, No. 2 mesh.
Description. Measurements in mm: total length 39.2 (27.3–43.6), head 3.8 (3.1–4.0), snout 1.2 (1.1–1.7), eye 0.8 (0.9–1.0), upper jaw 1.9 (1.4–2.1), postorbital 1.9 (1.3–2.0), pectoral 0.9 (0.6–1.2), preanal 30.9 (21.3–33.6), predorsal 25.8 (19.6–31.1), depth just before eye 1.7 (1.5–2.1), depth at pectoral origin 3.4 (2.4–4.0), depth at midpoint between pectoral and vent 8.6 (5.0–8.8), page 7 depth at anal origin 6.8 (4.1–8.4). Branchiostegal and pectoral rays not obvious, dorsal rays before level of vent 89 (91 and 82 in the two largest specimens), total rays 256 (256 and 253), first dorsal ray at level of segment 62 (61 in the two largest specimens), anal rays 200 (183–225), caudal rays 3 + 2 + 2 + 2 (variable, usually 2 + 2 + 2 + 2). Teeth . Myomeres 73 + 34 = 107 (106–110). a–d = 9 (8–9). 1st vertical blood-vessel at 16 (15–17), 2nd at 37 (37–39), 3rd at 43 (43–44). Anterior margin of gall-bladder at level of 25th or 31st myomere.
Body elongate, but not excessively so, much compressed but relatively deep, its maximum depth contained a little more than four times in the total length, tapering equally in front of and behind midpoint of body. Head short, about one-tenth of total length, indented at the throat, pointed, with the dorsal profile slightly convex; anterior and posterior nostrils clearly separated; eye contained one and a-half times in snout, oval, with the greatest diameter vertical; cleft of mouth oblique, extending to level of middle of pupil; teeth conspicuous, very acute, 18 in upper jaw projecting outside those of lower jaw, distributed as follows: first tooth minute, needle-like, directed immediately forwards and placed on the anterodorsal surface of the snout above the second tooth, which is a much larger anteriorly-directed grasping tooth; these two are followed by a second series of large, needle-like fangs and a third of much smaller teeth to a point below the middle of the pupil; the teeth of the lower jaw are similar in grouping and size to those of the upper jaw. Branchiostegal rays not obvious. Pectoral fin large, about equal to vertical diameter of eye, rounded, base of fin fleshy but with the rays not obvious. Dorsal fin low with the rays well developed only in the larger specimens but the radials always countable. Anal fin a little higher than the dorsal. Caudal fin in the larger specimens well marked off from the dorsal and anal fins and with well developed hypurals and fin-rays.
Colour in preservative translucent with pigment restricted to the chorioid of the eye.
Remarks. These six specimens are long-finned larvae, having 8–9 myomeres between the origins of the dorsal and anal fins compared with about 5 in short-finned species. They have 106–110 myomeres. These two characters, taken together with the location of capture of the six larvae, restrict the identification to either A. reinhardti or A. marmorata. However, it is difficult to refer these larvae further to either one or other of these two species or both since the definitive adult characters are relatively insignificant and are not exhibited in the larvae. There is evidence, nevertheless, to show that these larvae represent two species. I have examined a large number of leptocephali of the Genus Gnathophis (Congridae) including a wide range of sizes for two species. In this case, the segmental level of the gall-bladder is the same in both species and does not change with growth. In the present six specimens, the two smallest larvae (27.3mm and 27.6mm) have the gall-bladder at the level of the 31st myomere, but in the other four specimens the gall-bladder is level with myomeres 24 and 25. From this I consider that there are two species in this particular group of six larvae. The two smallest larvae with a more posterior gall-bladder were collected in the northerly region of the area known for the adult A. reinhardti. The four larger were taken in the southern part of the known distribution of A. marmorata. Since the areas occupied by the adults overlap only in New Caledonia, and since two larval species are indicated, further work may confirm my proposed identifications.page 8