Nomorhamphus lanceolatus, Huylebrouck & Hadiaty & Herder, 2014

Huylebrouck, Jan, Hadiaty, Renny Kurnia & Herder, Fabian, 2014, Two new species of viviparous halfbeaks (Atherinomorpha: Beloniformes: Zenarchopteridae) endemic to Sulawesi Tenggara, Indonesia, Raffles Bulletin of Zoology 62, pp. 200-209 : 201-204

Nomorhamphus lanceolatus , new species

( Figs 1–4 , 7 ; Table 1)

Material examined. Holotype – MZB 21299 (40.8 mm SL), male, Indonesia, Sulawesi, Southeast Sulawesi Province, Regency of Kolaka Utara, Wawolambo River , near the bridge on the road, between Kolaka and Kendari, 04°02'51.6"S 121°42'40.8"E, R. K. Hadiaty, D. Wowor & S. Sauri, 8 July 2011.

Paratypes. MZB 21300, 3 males (30.5–43.0 mm SL), 2 females (36.4–53.8 mm SL), all collected with the holotype; ZFMK 49526–49529, 2 males (33.7–34.8 mm SL), 2 females (45.3–48.9 mm SL), all collected with the holotype; ZMH 25920–25921, 1 male (33.6 mm SL), 1 female (49.2 mm SL), all collected with the holotype; WFB 3125–3128, 2 males (32.5–33.4 mm SL), 2 females (33.7–49.8 mm SL), all collected with the holotype.

Additional non-type material. MZB 20455, 3 immature females (22.5–25.7 mm SL), 4 undet. (16.6–19.5 mm SL), all collected with the holotype.

Diagnosis. Nomorhamphus lanceolatus is distinguished from all other Nomorhamphus by the combination of the following characters: lower jaw short; absence of a fleshy lower jaw appendage in males; presence of black pigmentation in anal and dorsal fin, life colouration with yellow and orange coloured anal, dorsal, and caudal fin, ventral surface of lower jaw orange and yellow belly; a lanceolate, dorsally slightly curved spiculus in the male andropodium, with the middle segments of the spiculus in contact with the distal tip of the third anal-fin ray ( Fig. 1 ); nine to ten segments proximal to spinae (mode nine segments); segments three or four to six or seven (mode four to seven) of second anal-fin ray in males with a dorsal and a ventral row of “subsegments” forming small squares and rectangles of different sizes, so that these segments seem to be subdivided; third anal-fin ray slightly constricted longitudinally, giving the appearance of two distinct rays, distal part of this ray is slightly curved ventrally to contact spiculus.

Description. Morphometric and meristic characters are provided in Table 1. Body deep, BDP 1 18.2–20.6 % SL, BDP 2 17.9–21.4% SL. Lower jaw short (LJLB 15.0–25.3 times in SL), upper jaw longer than wide (UJL/UJW 1.2–1.4). Eye relatively large, bony orbital diameter 20.0–22.9% HDL. One row of conical teeth at the front of the upper and lower jaws, followed by three rows of conical teeth up to the end of the jaws. Gill rakers tear-drop shaped, without teeth on the dorsal surface of the gill rakers. Vertebrae number 36–38 [37]. Predorsal scales deeply embedded. Anal-fin rays 15–16 [15]. Dorsal-fin origin over anal-fin ray 2, 3 or 4 [3]. Dorsalfin rays 11–13 [12]. Pectoral-fin rays 13. Pelvic-fin rays 6. Fifth hypural fused to dorsal hypural plate. Caudal peduncle depth 8.7–9.8% SL. Caudal fin truncate, principal caudal-fin rays i,5–6/5–6,i (mode and holotype i,6/6,i), procurrent caudal-fin rays 5–7/5–6 (mode 6/5; holotype 5/5).

Life colouration. Body yellowish brown ( Fig. 2 ). Ventral surface of lower jaw orange. Interoperculum and belly yellow. Iris grey with a yellow edge. Diffuse black, oval spot anterior to the pectoral fin and distinct black, oval spot on the base of the pectoral fin, proximal part of the pectoral-fin rays yellowish hyaline, which merges into transparent distally. Pelvic fins yellow. Base of dorsal-fin rays and anal-fin rays yellowish hyaline, distal parts light orange with black pigment on distal tips of posterior fin rays, in females small black parts on distal half of anterior dorsal-fin rays and anal-fin rays. Base of caudal fin yellowish hyaline, followed by an orange hyaline part.

Preserved colouration. Background colour beige ( Fig. 3 ) with thin mid-lateral stripe from pectoral to caudal fin, more prominent posteriorly. Distinct oval spot on pectoral-fin base. Uniform distribution of melanophores on the head and on the dorsal and flank of the trunk; high concentration of melanophores anterior and dorsal to the distinct oval spot on pectoral-fin base. Black pigment on distal tips of posterior dorsal-fin rays and on distal tips of posterior anal-fin rays. In larger females black pigment on distal half of anterior dorsal-fin rays and anal-fin rays.

Sexual dimorphism. Females grow larger than males (maximum SL recorded: 43.0 mm in males, 53.8 mm in females). Males with andropodium.

Distribution and habitat. Nomorhamphus lanceolatus is known from Sungai Wawolambo in Sulawesi Tenggara, Indonesia ( Fig. 5 ). The stream belongs to the Sampara river basin. The holotype and the paratypes were taken from a locality near the bridge on the road between Kolaka and Kendari. The stream of this locality (04°02'51.6"S 121°42'40.8"E) is about 7–9 m wide and 50 cm deep, partially shaded by forest canopy, with a bed of sand and gravel ( Fig. 6 ).

Etymology. From the late Latin adjective lanceolatus (“lanceolate”), in allusion to the shape of the spiculus of the new species.

Comparisons. In contrast to other Nomorhamphus species from Sulawesi with exception of N. sagittarius , N. lanceolatus has a characteristic lanceolate male spiculus, and is further distinguished by the presence of a black spot on the base of the pectoral fin (absent in all other Nomorhamphus , except of N. sagittarius ). Nomorhamphus lanceolatus is distinguished from N. sagittarius by having a short lower jaw approximately equal in length of the upper jaw (LJLB 15.0–25.3 times in SL vs. 6.4–15.0 times in SL in N. sagittarius ), and by the black pigmentation of the dorsal and anal fins lacking in N. sagittarius . Among other characters, the new species differs from N. megarrhamphus and N. weberi by having a first anal-fin pterygiophore which is thickened and not angled anteriorly (see Meisner, 2001) and a much less elongated lower jaw (lower jaw length following Brembach 15.0–25.3 times in SL in N. lanceolatus , vs. 4.0–5.7 times in SL in N. megarrhamphus and 3.7–4.9 times in SL in N. weberi ; Meisner, 2001). Furthermore, the new species is distinguished from N. megarrhamphus and N. weberi by a yellowish brown body colouration (vs. a silvery-bluish life colouration in N. megarrhamphus and N. weberi ) and the absence of a large concentration of melanophores on the dorsal surface (vs. presence in preserved condition in N. megarrhamphus and N. weberi ; Meisner, 2001). The new species is distinguished from N. brembachi and N. liemi by lacking a fleshy appendage of the lower jaw in males. In N. brembachi and N. liemi , the second male anal-fin ray is curved at approximately ¼ its length so that the distal ½ slopes ventrally (see Meisner, 2001). Nomorhamphus lancoelatus is distinguished from N. rex , N. ebrardtii , and N. kolonodalensis by its shorter lower jaw (LJLB 15.0–25.3 times in SL vs. 5.7–11.3 in N. rex , 13.4–15.9 in N. ebrardtii and 8.8–22.2 in N. kolonodalensis ; Meisner & Louie, 2000; Meisner, 2001; Huylebrouck et al., 2012), having the fifth hypural plate completely fused to the dorsal hypural plate (vs. the fifth hypural partially separate from the dorsal hypural plate along most of its length in N. kolonodalensis ; Meisner & Louie, 2000), and presence of black pigments on distal tips of posterior dorsal- and anal-fin rays (vs. no fin pigmentation in N. ebrardtii ; Brembach, 1991).

The habitus of Nomorhamphus lanceolatus is most similar to N. celebensis and N. towoetii . Nomorhamphus lanceolatus is however clearly distinguished from these species by the shape of the spiculus, which is lanceolate (vs. a straight spiculus that is not noticeably thickened in N. celebensis and N. towoetii ; Meisner, 2001), and by the painted life colouration composed of yellow- and orange-coloured anal, dorsal and caudal fin, orange-coloured ventral surface of lower jaw, and yellow-coloured belly (vs. grey to black bodies in N. celebensis and N. towoetii ). The new species is distinguished from N. celebensis by its comparatively narrow upper jaw (UJL/UJW 1.2–1.4 in N. lanceolatus vs. 0.70–0.94; Meisner, 2001), and from N. towoetii by its yellowish brown body colouration (vs. olive body with a large concentration of melanophores on lateral and dorsal body surfaces, which gives females a dusky appearance whereas large males are completely melanistic in N. towoetii ; Meisner, 2001).

The shape of the andropodium, viz the elongated spiculus, of Nomorhamphus lanceolatus is superficially similar to certain species of Nomorhamphus endemic to the Philippines, including N. bakeri , N. manifesta , N. pectoralis , N. philippina , N. vivipara , and N. pinnimaculata . Nomorhamphus lanceolatus differs from these however in lower jaw length (LJLB 15.0–25.3 times in SL vs. 5.1 times in SL in N. bakeri , 6.1–11.5 times in SL in N. manifesta , 6.9–18.6 times SL in N. pectoralis , 10.4–18.8 times in SL in N. philippina , 5.6–20.6 times in SL in N. pinnimaculata , 4.5–8.3 times in SL in N. rossi and 5.3–7.9 times in SL in N. vivipara ; Meisner, 2001), the lanceolate spiculus which is curved dorsally (vs. slender and curved ventrally in N. bakeri , N. manifesta , N. pectoralis , N. philippina , N. vivipara , and N. pinnimaculata respectively short and thick in N. rossi ; Meisner, 2001), and the presence (vs. absence) of a distinct black spot on the base of the pectoral fin. With exception of N. pectoralis , the new species is distinguished by the fifth hypural plate which is fused to the dorsal hypural plate (vs. fifth hypural plate separate from the dorsal hypural plate among most of its length; see Fig. 7 ; Meisner, 2001). Nomorhamphus pectoralis is distinguished from N. lanceolatus by a dorsally offset spiculus giving the anal-fin ray an appearance of a small step located at the spines (vs. no offset spiculus in N. lanceolatus ; Meisner, 2001).

Figures

Fig. 1. Diagrammatic representation of the modified anal-fin rays (andropodium) of Nomorhamphus lanceolatus and N. sagittarius, MZB 20443, 35.0 mm SL, cleared and stained male specimen of N. sagittarius. Scale bar = 1 mm. SN, Spinae; SP, Spiculus.

Fig. 2. A, B, Nomorhamphus lanceolatus; Indonesia, Sulawesi: Sulawesi Tenggara; Wawolambo River, near the bridge on the road, between Kolaka and Kendari, 04°02'51.6"S 121°42'40.8"E (© R. K. Hadiaty). A, male; B, female.

Fig. 3. A, Nomorhamphus lanceolatus, MZB 21299, holotype, 40.8 mm SL, male, right side, reversed; B, MZB 21300, paratype, 53.8 mm SL, female.

Fig. 4. Radiograph of Nomorhamphus lanceolatus. A, MZB 21299, holotype, 40.8 mm SL, male; B, MZB 21300, paratype, 53.8 mm SL, female.

Fig. 7. Diagrammatic representation of the caudal skeleton of Nomorhamphus lanceolatus, MZB 21299, holotype, 40.8 mm SL, male. Scale bar 500 μm. EP, epural; HY, hypural. The hook shaped first epural is only present in the holotype; all other specimens exhibit a straight first epural.

Fig. 5. Map of Sulawesi with highlighted sampling locations. Star, sampling locations of N. sagittarius; Square, sampling location of N. lanceolatus (© map T. von Rintelen, modified).

Fig. 6. Wawolambo River, type locality of Nomorhamphus lanceolatus (© R. K. Hadiaty).