Pinjalo lewisi Randall, Allen and Anderson

Leis, Jeffrey M, 2008, Larval development in the lutjanid subfamily Lutjaninae (Pisces): the Indo-Pacific genus Pinjalo, Zootaxa 1760, pp. 37-49 : 43-48

Pinjalo lewisi Randall, Allen and Anderson

Fig. 3, Table 4

1 flexion-stage and 22 postflexion, pelagic larvae, 5.6–15.0 mm. Western Indian Ocean: West coast of Sumatra AMS I.34606-003, AMS I.34607-006, -007, -008 ZMUC Dana, 3861 II+IV, 3867 I-II-III-IV, 3868 I 350mw. Western Pacific: Macassar Strait, ZMUC Dana, 3796 II 200mw; Molucca Sea LACM 36065-38; Halmahera Sea LACM 36086-8; Celebes Sea LACM 36029-14; Banda Sea ZMA 121.165; Northern Coral Sea AMS I.43102-009, I.43103-016, I.43105-003, I.43905-008.

Diagnosis: Pinjalo lewisi can be distinguished from P. pinjalo by fin meristics, and the relative lengths of the fin spines ( Table 3). In P. l e w i s i, DspI is relatively large (68–90% DspII), and P2sp is long relative to DspII (98–121% DspII, 27–36%BL).

Description: Body compressed and deep (39–45% at P1 base, and about 10% less at anus), without any clear changes with growth. The gut is coiled and triangular, and in most of the available specimens, the gas bladder is prominent. There is no gap between the anus and anal fin. The tail is relatively small tapering to a small caudal fin. The head is large (41–48%) and compressed. The eye is large (32–38% HL) and round. The snout is triangular and somewhat smaller than the orbit (71–87% ED). The profile of the head is straight to slightly convex and moderately sloped. The nasal pit is bridged over by 8.8 mm. The mouth is large, reaching to between the anterior edges of the eye and the pupil, and is only slightly oblique — at most, about 35° from the horizontal. Prominent teeth on the premaxilla, including enlarged, anterior canines, are present in all specimens.

Spination on the head is extensive and well developed. The inner border of the preopercle has 2–3 upperlimb spines in the smallest specimens, increasing to 6 by 13 mm, and 4 lower-limb spines, increasing to 7 by 12 mm: all are smaller than those on the outer border. The spine at the angle of the preopercle is large and robust: in the smallest larvae it is 18%, reaching to the base of the pelvic-fin spine, but in the largest larvae, it is 8%, reaching only to the base of the pectoral fin. The upper limb of the outer border of the preopercle has only a single spine of moderate length until at about 9 mm, when a small, second spine forms: in the largest larvae, 4 (1 moderate, and 3 small) spines are present. On the lower limb of the outer border, there are 4–5 spines in the smallest larvae, increasing to 5–6 by 6 mm, and 7 in the largest larvae. These spines are graduated in size, with the smallest spines at the anterior end: the posterior-most spine is second in size amongst head spines only to the spine at the angle. The preopercular spines are smooth except those at and near the angle. From about 7–8 mm, the spine at the preopercular angle and the spine on the outer, lower limb immediately adjacent to it, and in some individuals, the next anterior outer, lower-limb spine have very fine serrations. The 12.3 mm specimen lacks serrations on preopercular spines, but this may be due to damage. The anterior-most edge of the maxilla also has very fine serrations except the 14.5 mm specimen. A single, small interopercular spine is present in all specimens. There are no subopercular spines. A single spine on the opercle is present in all specimens, and becomes more prominent in larger larvae. The supraocular ridge is serrate, with 4 spines in the smallest specimen, increasing to 9 spines in the largest specimens. Spineless ridges form anteriorly on the frontal at 7.9 mm, and on the pterotic at 6.1 mm.

Spination on the pectoral girdle is also well developed. A small postcleithral spine and 3 prominent supracleithral spines are present in all specimens, except the 13 mm specimen, which has 4 supracleithral spines. At about 6 mm, a prominent ridge forms on the cleithrum just dorsal to the pectoral base, more or less in line with the increasingly prominent postcleithral spine. There is a single ventral posttemporal spine. A single dorsal posttemporal spine may increase to 2 by 6 mm, and 3 by 11 mm, but larvae as large as 10.8 mm may have only 1.

The smallest specimen is very late flexion stage, and has 9+8 principal caudal rays, DXII,13, AIII,9 and P 2 I,5 (the adult complement of elements of these fins), but only 7 rays in the pectoral fin. The fin spines are robust, and trailing edges of all fin spines eventually acquire strong serrations, as do the leading edges of all but the posterior most spines of the dorsal fin. DspII is the longest spine in the dorsal fin (27–33 %), but the other spines of this fin are also long, and taper gradually to the length of the fin rays. In particular, DspI is very long compared to other lutjanids, constituting 68–90% DspII. The smallest specimen has trailing edge serrations on DspI–VIII, and leading edge serrations on DspI–IV. DspI & II have a single, serrate leading edge ridge, but from about 6 mm a second serrate ridge may be present, and is present in all specimens from 9.8 mm. Trailing edge serrations are present on DspX by 7 mm, DspXI by 8.8 mm, and DspXII by 10.8 mm. The P2sp is the longest fin spine (except in two specimens in which it is 98–99% of DspII), constituting 27–35% BL and 97–121% DspII. P2sp has two, serrate leading-edge ridges that extend the length of the spine, and from about 8 mm, a partial third ridge may be present basally. P2 ray 1 is close to the length of P2sp, extending to near the tip of the spine in all specimens. AspIII is smooth and in the final stages of transforming from a soft ray at 5.7mm: at this size, the trailing edges of AspI&II are serrate, and only the leading edge of AspI has limited, weak serrations. AspII acquires leading edge serrations by 6 mm. AspIII remains the weakest of the anal-fin spines and does not acquire serrations until 11.3 mm. A full complement of P1 rays is present at about 8.2 mm.

Gill rakers increase from 3+1+12 at 8.8 mm, to 5+1+12 at 11.3 mm and to 7+1+16 at 15 mm. No scales are present in any of the available specimens.

Pigment: Pinjalo lewisi larvae are not heavily pigmented except on the membrane of the spiny dorsal fin, over the gut, on the fore and mid brains, especially of larger specimens, and on the caudal peduncle, both dorsally and laterally. In the smallest specimen, pigment is limited to: about 10 melanophores on each midbrain hemisphere, and one on each forebrain hemisphere; scattered melanophores on the membrane of the spiny dorsal fin between spines II–V; on the ventral edge of the tail, a single melanophore posteriorly on the peduncle, and one at the base of the last anal-fin ray; a single internal melanophore on the dorsal surface of the urostyle; a single small melanophore at the base of a ventral principal caudal-fin ray; and a thick saddle of pigment over the gas bladder extending ventrally over the anterior and lateral surfaces of the gut.

The brain pigment increases in density and number of melanophores and spreads so that by 7 mm, there are about 20 melanophores on the dorsal surface of the midbrain and about 10 on the forebrain, and this increases until both portions of the brain are heavily covered with melanophores. Melanophores form from as early as 6 mm at the base of the opercular spine and on the dorsal surface of the snout and anterior tips of the lips and chin, and spread slowly in these vicinities. A small cluster of melanophores forms at the 5 o'clock position of the eye from about 8 mm.

FIGURE 3. Postflexion-stage larvae of Pinjalo lewisi . Unless stated otherwise, in both dorsal and anal fins, the spines have a single leading-edge ridge, and two trailing-edge ridges, and the P2sp has two leading-edge ridges, and two trailing-edge ridges. Not all ridges are visible in the illustrations. Scale bars = 1 mm. A. 5.7 mm larva from the eastern Indian Ocean off the west coast of Sumatra (AMS I.34606-003). The posterior-most spine in the dorsal fin is transforming from a soft ray. B. 7.1 mm larva from the eastern Indian Ocean off the west coast of Sumatra (AMS I.34607-008). The P2sp on the left side is broken, and an outline of its length is provided from the right P2 fin. Note very fine serrations on the anterior portion of the maxilla. The anterior spines of the dorsal fin have two leading edge ridges, both of which are serrate.

No pigment forms on any of the anal, pectoral or pelvic fins. A single caudal fin-base melanophore is present in most specimens, and this constitutes the only caudal-fin pigment. In contrast, the dorsal fin is heavily pigmented. On the membrane of the dorsal fin, pigment spreads both posteriorly and ventrally, and increases in density. The pigment is between DspII and VIII at 7 mm, DspI and XI by 8.8 mm, and DspI and XII at 11.3 mm. The pigment remains limited to the distal portions of the fin membrane of spines I–III, but reaches the fin base in more posterior spines, eventually spreading onto the dorsal-most portions of the body in specimens as small as 9 mm. This fin-membrane pigment extends onto the soft-ray portion of the dorsal fin in the largest specimens. In the 15 mm specimen, the dorsal pigment on the back extends from the brain to the anterior edge of DspI, then irregularly along the dorsal-fin base to the caudal peduncle patch described below.

FIGURE 3 (continued). Postflexion-stage larvae of Pinjalo lewisi . Unless stated otherwise, in both dorsal and anal fins, the spines have a single leading-edge ridge, and two trailing-edge ridges, and the P2sp has two leading-edge ridges, and two trailing-edge ridges. Not all ridges are visible in the illustrations. Scale bars = 1 mm. C. 8.8 mm larva from the western Pacific Ocean in the Halmahera Sea (LACM 36086-8). Note very fine serrations on the anterior portion of the maxilla and on two preopercular spines. The anterior spines of the dorsal fin have two leading edge ridges, both of which are serrate. D. 11.3 mm larva from the western Pacific Ocean in the Banda Sea (ZMA 121.165). Note very fine serrations on the anterior portion of the maxilla and on the largest preopercular spine. DspI is broken near the base. The anterior spines of the dorsal fin have two leading edge ridges, both of which are serrate.

From about 8–9 mm, a dense patch of melanophores forms at the dorsal, anterior edge of the caudal peduncle, eventually reaching mid-peduncle. There is pigment on the urostyle in all specimens but one (5.7 mm), consisting until 7.3 mm of a single, small internal melanophore on the dorsal surface. In larger specimens, this spreads, both dorsally and ventrally to the urostyle, and from about 8.8 mm, extends to the lateral, external surfaces of the tail.

Ventrally, pigment on the tail remains limited to a single melanophore on the peduncle and a single melanophore at the base of the posterior-most rays of the anal fin, although the former is absent in the largest specimen. There is no pigment on the ventral surface of the trunk or head, except that a single melanophore is present at the cleithral symphysis in two specimens: 5.7 & 6.0 mm.

Remarks. It is possible that the fine serrations on the largest spines on the preopercle result from an irregular erosion of the surface of the spines, rather than being serrations per se, and that this becomes evident only in specimens kept in particular conditions (eg, under-buffered formalin). The fine serrations on the maxilla are more consistently present than those on the preopercular spines. In any case, such very fine serrations occur amongst Indo-Pacific lutjanine lutjanid larvae only in the two Pinjalo species and in larvae of the Lutjanus erythropterus / malabaricus group ( Leis and Rennis 2004). Although the larvae of the Atlantic genus Rhomboplites have serrations on the spine at the angle of the preopercle, it is not clear if this is the same condition, and Rhomboplites apparently lacks serrations on the maxilla (Laroche 1997).

Tables

TABLE 4. Meristic and morphometric information on Pinjalo lewisi larvae. Lower-case Roman numerals in square brackets indicate a soft ray in transition to a spine. Arabic numerals in square brackets indicate base, but not ray, formed. An entry of d indicates damaged. Body Depth (P) and (A), indicate depth at pectoral-fin base and at anus, respectively.

Body Preanal Length Length	Predorsal Length	Head Length	Orbit Diameter	Snout Length	Body Depth (P)	Body Depth (A)	DspI Length	DspII Length	P2 sp Length	Dorsal Fin	Anal Fin	Pectoral Fin
Flexion
5.62 3.45	2.35	2.70	0.88	0.72	2.22	1.75	d	1.65	2.00	XII,13	III,9	7
Postflexion
5.69 3.36	2.43	2.55	0.94	0.68	2.32	1.69	1.25	1.74	1.70	XI(i),13	II(1),9	8
6.00 3.73	2.40	2.61	0.87	0.80	2.69	1.94	1.47	d	1.96	XII,14	III,9	9
6.05 4.02	2.50	2.64	0.99	0.71	2.62	1.97	1.05	d	1.94	XII,13	II(1),9	12
6.12 3.82	2.57	2.89	1.05	0.75	2.50	1.87	1.37	1.81	d	XI(i),13	II(1),9	10
6.30 4.20	2.72	2.87	1.05	0.83	2.74	1.92	1.51	1.92	2.07	XII,13	III,9	10
6.97 4.58	2.93	3.23	1.13	0.94	2.81	1.97	1.70	2.08	2.27	XII,13	III,8	9
7.08 4.64	2.91	3.17	1.13	0.82	2.94	2.16	1.55	2.27	2.30	XII,13	III,9	14
7.28 4.68	2.75	3.39	1.22	0.89	3.08	2.17	1.70	2.08	2.25	XI(i),13	II(i),9	18
7.64 4.45	2.88	3.64	1.19	1.00	3.05	2.50	1.76	2.39	2.37	XI(i),13	III,9	15
7.81 5.26	3.07	3.66	1.26	1.02	3.02	2.30	2.08	2.54	2.66	XII,13	III,9	15
7.91 5.47	3.37	3.81	1.26	1.04	3.17	2.29	1.96	d	2.62	XII,13	III,9	13
8.10 5.32	3.05	3.66	1.31	1.01	3.15	2.33	2.09	2.61	2.78	XII,13	III,9	16
8.17 5.43	3.10	3.62	1.32	1.15	3.19	2.40	2.00	d	2.46	XII,13	III,9	18
8.74 5.87	3.39	3.92	1.26	1.10	3.45	2.98	2.04	2.60	2.79	XII,13	III,9	17
8.75 5.93	3.40	4.07	1.37	1.08	3.70	2.74	2.02	2.52	2.85	XII,13	III,9	18
9.81 6.45	3.86	4.37	1.52	1.17	4.22	3.28	1.88	d	2.66	XII,13	III,9	17
10.80 7.47	4.27	4.58	1.70	1.43	4.57	3.28	2.46	3.11	3.40	XII,13	III,9	-
11.27 6.63	4.50	5.02	1.65	1.38	4.68	3.98	d	3.72	3.83	XII,13	III,9	18
12.10 8.20	4.40	5.20	1.70	1.40	5.10	3.90	3.10	3.50	3.90	XII, 13	III,9	18
13.20 9.65	4.88	5.65	1.92	1.46	5.65	4.11	3.25	3.60	4.18	XII,13	III,9	18
14.50 9.80	5.30	6.30	2.00	1.70	6.00	4.70	3.50	4.00	4.50	XII,13	III,9	18
15.00 10.30	5.20	6.20	2.00	1.50	6.10	4.40	d	4.10	4.50	XII,13	III,9	18