Nomorhamphus sagittarius, 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 : 204-208

Nomorhamphus sagittarius , new species

( Figs 8–10 , 12 ; Table 2)

Material examined. Holotype – MZB 21301 (42.8 mm SL), male, Indonesia, Sulawesi, Southeast Sulawesi Province, Regency of Kolaka Utara, District Kolaka, Village Ulunggolaka , Mangolo River , R. K. Hadiaty, D. Wowor & S. Sauri, 5 July 2011.

Paratypes. MZB 21302, 1 male (30.5 mm SL), 6 females (51.6–72.5 mm SL), all collected with the holotype ; MZB 21303, 2 males (33.4–37.1 mm SL), 2 females (49.5–60.6 mm SL), Mangolo River , about 500 m away from locality of holotype, 03°58'56.6"S 121°34'05.5"E , R. K. Hadiaty, D. Wowor & S. Sauri , 5 July 2011 ; MZB 21304, 2 males (38.0– 38.3 mm SL), 2 females (52.8–54.7 mm SL), Regency of Kolaka Utara , District Kolaka , Village Ulunggolaka, Tawo-Tawo River, 03°59'08.8"S 121°33'45.5"E , R. K. Hadiaty, D. Wowor & S. Sauri , 7 July 2011 ; MZB 21305, 1 male (30.6 mm SL), 3 females (50.2–51.7 mm SL), Watumbasi River , 03°59'07.2"S 121°34'10.7"E , R. K. Hadiaty, D. Wowor & S. Sauri , 7 July 2011 ; ZFMK 49530–49531 , 1 male (37.2 mm SL), 1 female (67.0 mm SL), same data as MZB 21302 ; ZFMK 49532–49533 , 1 male (36.7 mm SL), 1 female (59.5 mm SL), same data as MZB 21303 ; ZFMK 49534–49535 , 1 male (38.9 mm SL), 1 female (60.3 mm SL), same data as MZB 21304 ; ZFMK 49536–49537 , 1 male (39.7 mm SL), 1 female (65.1 mm SL), same data as MZB 21305 ; ZMH 25922–25923 , 1 male (38.1 mm SL), 1 female (60.8 mm SL), same data as MZB 21304 ; ZMH 25924–25925 , 1 male (32.3 mm SL), 1 female (66.1 mm SL), same data as MZB 21305 ; WFB 3129–3130, 1 male (39.3 mm SL), 1 female (63.9 mm SL), same data as MZB 21304 ; WFB 3131–3132, 1 male (33.3 mm SL), 1 female (65.7 mm SL), same data as MZB 21305 .

Additional non-type material. MZB 20437, 5 males (26.4–33.8 mm SL), 10 females (33.1–76.5 mm SL), 1 undet. (22.9 mm SL), all collected with the holotype; MZB 20431, 6 males (24.4–37.2 mm SL), 5 females (32.4–66.9 mm SL), 4 undet. (12.7–22.1 mm SL), same data as MZB 21303; MZB 20443, 45 males (25.1–38.1 mm SL, of which one specimen has been cleared and counterstained), 33 females (27.8–55.4 mm SL), 26 undet. (16.5–26.3 mm SL), same data as MZB 21304; MZB 20452, 4 males (27.3–31.9 mm SL), 13 females (32.0– 51.4 mm SL), 1 undet. (18.5 mm SL), same data as MZB 21305.

Diagnosis. Nomorhamphus sagittarius is distinguished from all other Nomorhamphus by the following combination of characters: lower jaw elongated; one to seven teeth along dorsal surface of extended portion of lower jaw (absent in some specimens); fins and ventral surface of lower jaw orange; black fin pigmentation absent; a distinct black spot on the base of the pectoral fin; a lanceolate, dorsally slightly curved spiculus in the male andropodium, its middle segments in contact with the distal tip of the third anal-fin ray ( Fig. 1 ); seven to ten segments proximal to spinae (mode eight); segments three to seven (mode three to five) 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. Some males (78.6% of the adult male type specimens) with an elongated fourth or fifth segment (mode fifth) in second anal-fin ray. 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 2. Body deep, BDP 1 16.1–19.1% SL, BDP 2 17.5–20.7% SL. Lower jaw elongate (LJLB 6.4–15.0 times in SL), upper jaw longer than wide (UJL/UJW 1.3–1.8). Eye relatively large, bony orbital diameter 15.7–21.7 % 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 upper and lower jaws in larger females. Males and smaller females with one row of conical teeth at the front of the upper and lower jaws, followed by two rows of conical teeth up to the end of the upper jaw and three rows up to the end of the lower jaw. Gill rakers tear-drop shaped, without teeth on the dorsal surface of the gill rakers. Vertebrae number 37–39 [39]. 46–54 predorsal scales. Anal-fin rays 14–17 [17]. Dorsal-fin origin over anal-fin ray 3, 4, 5 or 6 [5]. Dorsal-fin rays 11–13 [12]. Pectoral-fin rays 11–12 [12]. Pelvic-fin rays 6. Fifth hypural fused to dorsal hypural plate. Caudal peduncle depth 7.5–9.2% SL. Caudal fin truncate, principal caudal-fin rays i,6/6,i, procurrent caudal-fin rays 5–6/4–5 (mode and holotype 5/5).

Life colouration. Body brown ( Fig. 8 ). Ventral surface and distal tip of lower jaw orange. Iris light yellowish. Very diffuse black, oval spot anterior to the pectoral fin and a distinct black, oval spot on the base of the pectoral fin; distal tips of pectoral fins orange. Proximal half of pelvic fins yellowish hyaline; distal half of pelvic fins orange. Bases of dorsal, anal and caudal fin yellowish hyaline; distal parts of the dorsal, anal and caudal fin orange. Black pigment absent in all fins.

Preserved colouration. Background colour beige ( Fig. 9 ) with thin midlateral stripe from pectoral to caudal fin, more prominent posteriorly. Distinct oval spot on the base of the pectoral fin. 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 absent in all fins. Small black spot on the base of any pelvic fin.

Sexual dimorphism. Females grow larger than males (maximum SL recorded: 39.7 mm in males, 72.5 mm in females). Males in average with a longer lower jaw (SL/ LJLB 6.4–10.8 vs. 6.9–15.0 in females) and with larger eyes compared to their head length (18.5–21.7 ORBL in % HDL vs. 15.7–18.5 in females). Males with andropodium.

Distribution and habitat. Nomorhamphus sagittarius is known from three streams in Sulawesi Tenggara, Indonesia ( Fig. 5 ). The Sungai Mangolo is about 6–8 m wide and 10–100 cm deep with a sandy and rocky bottom and clear water at the type locatlity near the Scout Camping Ground of the Forestry Department area ( Fig. 11 ). The second sample site from Sungai Mangolo is characterised by murky water due to traditional gold mining in the area. The river is about 5–7 m wide, 10–50 cm deep and moderate running with a few boulders and stones at this point and is covered by rain forest canopy (03°58'56.6"S 121°34'05.5"E). The Mangolo River belongs to the Mangolo river basin; the tributaries are the Sungais Tawo-Tawo and Watumbasi, which are the other two localities of N. sagittarius . Sungai Tawo-Tawo is about 3–5 m wide and 10–50 cm deep at the sample site (03°59'08.8"S 121°33'45.5"E). This habitat is characterised by a sandy and gravel bottom and by clear water with much riparian vegetation. The Sungai Watumbasi locality is 1–3 m wide, 10–30 cm deep and is characterised by a muddysandy bottom (03°59'07.2"S 121°34'10.7"E).

Etymology. From the Latin sagittarius , an archer, in allusion to the body shape of the new species, reminiscent of the shape of an arrow. A noun in apposition.

Comparisons. In contrast to other Nomorhamphus species from Sulawesi, with exception of N. lanceolatus , N. sagittarius has a characteristic lanceolate spiculus in males, a distinct black spot on the base of the pectoral fin and a few teeth along the dorsal surface of the extended portion of the lower jaw (absent in all other Nomorhamphus ). Nomorhamphus sagittarius is distinguished from N. lanceolatus by having an elongated lower jaw (LJLB 6.4–15.0 times in SL vs. upper and lower jaw approximately equal in length in N. lanceolatus, LJLB 15.0–25.3 times in SL) and by the pigmentation of the pelvic, dorsal and anal fin which is lacking in N. sagittarius . The new species is distinguished 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 6.4–15.0 times in SL in N. sagittarius , 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 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 anal-fin ray in males is curved at approximately ¼ its length so that the distal ½ slopes ventrally (see Meisner, 2001). In addition, N. brembachi , N. liemi , N. celebensis , and N. towoetii are characterised by lacking an elongate lower jaw and instead, have an upper and lower jaw approximately equal in length ( Meisner, 2001). The painted life colouration with orange coloured fins and ventral surface of lower jaw distinguishes N. sagittarius from N. celebensis and N. towoetii (grey to black bodies in N. celebensis and N. towoetii ). Nomorhamphus sagittarius is distinguished from N. rex and N. kolonodalensis by its absence of black pigment on fin rays (vs. black pigment on distal tips of dorsal- and anal-fin rays in N. kolonodalensis and N. rex ; Meisner & Louie, 2000; Huylebrouck et al., 2012) and fifth hypural plate completely fused to dorsal hypural plate (vs. fifth hypural partially seperate from dorsal hypural plate along most of its length in N. kolonodalensis ; Meisner & Louie, 2000). The new species is distinguished from N. ebrardtii by the dorsal-fin origin over anal-fin ray 3–6 (vs. 6–7 in N. ebrardtii ; Meisner, 2001).

The habitus of Nomorhamphus sagittarius is most similar to the seven species of Nomorhamphus endemic to the Philippines. Nomorhamphus sagittarius is clearly distinguished from these species by the absence of fin pigmentation (vs. black fin pigmentation in N. bakeri , N. manifesta , N. pectoralis , N. philippina , N. pinnimaculata , N. rossi , and N. vivipara ; see Meisner, 2001), 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, except in N. pectoralis ; Meisner, 2001), a few teeth along dorsal surface of the extended portion of the lower jaw and a distinct black spot on the base of the pectoral fin (vs. absent in all of these species). Nomorhamphus sagittarius is distinguished from N. pectoralis by the centrally offset spiculus (vs. spiculus offset dorsally in N. pectoralis ; Meisner, 2001). The new species is distinguished from N. philippina by the spiculus which is not clearly segmented, lanceolate, turned dorsally and the terminal segment is longer than the segmented region (vs. clearly segmented, slender, terminal segment turned ventrally and shorter than segmented region, Meisner, 2001). The male anal fin of N. sagittarius is most similar to those of N. vivipara , N. manifesta , and N. pinnimaculata in that the spiculus is elongate. The spiculus of the andropodium of the new species is curved dorsally (vs. curved slightly ventrally in N. vivipara , N. manifesta and N. pinnimaculata ; Meisner, 2001).

Remarks. Following Meisner (2001), the species described herein are clearly assigned to the genus Nomorhamphus (vs. Dermogenys , Hemirhamphodon , and Zenarchopterus ) by exhibiting the following combinations of characters: oval lacrimal; elongate, expanded autopalatine; teeth along the extended portion of the lower jaw absent in Nomorhamphus lanceolatus , and teeth not reaching to the frontal tip of the lower jaw in N. sagittarius ; uniserial teeth not extending medially in a concave row from outer row of teeth; modified anal-fin rays in males with a fleshy covering (cryptoplica); second anal-fin ray in males without a distinct geniculus; melanophores anterior to the anal fin in females not forming a distinct spot.

Comparative material. Nomorhamphus rex Indonesia, Sulawesi Selatan: Wewu River , 2°28.226'S 121°04.125'E; F. Herder & R. K. Hadiaty 4 May 2004: ZFMK 44944– 44955 , 12 ex. (paratypes, 7 females, 34.5–63.9 mm SL,

5 males, 28.9–41.5 mm SL). – Nomorhamphus ebrardtii Indonesia, Sulawesi Tenggara: Island of Wawoni ; D. Vogt July 1979: ZMH 7150 , 27 ex. (18 females, 38.0–60.0 mm SL, 9 males, 34.6–48.3 mm SL, of which two males are cleared and counterstained). – Nomorhamphus celebensis Indonesia, Sulawesi Tengah: Lake Poso ; L. R . Parenti 11 August 1995: MZB 6402 , 43 ex. (20 females, 29.5–60.4 mm SL, 23 males, 31.0– 39.5 mm SL). – Nomorhamphus kolonodalensis Indonesia, Sulawesi Selatan: stream near Nuha , 02°25.356'S, 121°21.426'E; J. Pfaender & J. Schwarzer 6 December 2002: ZFMK 48876–48944 , 69 ex. (24 females, 26.6–61.8 mm SL, 32 males, 25.6–44.3 mm SL, 13 undet., 15.8–21.8 mm SL). – Nomorhamphus towoetii Indonesia, Sulawesi Selatan: Sungai Balambano, about 500 m above Balambano (road from Malili to Soroako); M. Kottelat & A. K. Kloetzli 19 June 1988: MZB 5973 , 6 ex. (2 females, 39.3–49.4 mm SL, 3 males, 38.5–41.6 mm SL, 1 juv., 14.6 mm SL). – Nomorhamphus liemi Indonesia, Sulawesi Selatan: Highlands of Maros ; D. Vogt August 1978: ZMH 7157 , 35 ex. (paratypes of Nomorhamphus liemi snijdersi (synonym of N. liemi ( Meisner, 2001) , 22 females, 37.6–69.9 mm SL, 14 males, 36.4–45.6mm SL). – Nomorhamphus brembachi Indonesia, Sulawesi Selatan: Highlands of South Sulawesi, smaller mountain streams; D. Vogt May 1978: ZMH 7166 , 2 ex (paratypes, 1 female, 35.5 mm SL, 1 male, 38.7 mm SL). – Nomorhamphus brembachi Indonesia, Sulawesi Selatan: Highlands of Maros ; M. Brembach August 1978: ZMH 7160 , 13 ex. (paratypes of Nomorhamphus ravnaki ravnaki , synonym of N. brembachi ( Meisner, 2001) , 5 females, 55.8–77.0 mm SL, 4 males, 35.0– 37.8 mm SL, 4 undet., 18.0– 23.8 mm SL). – Nomorhamphus megarrhamphus Indonesia, Sulawesi Selatan: Lake Towuti, inlet of River Tominanga ; F. Herder & A. Nolte 28 November 2002: ZFMK 44923 , 1 ex. (female, 77.3 mm SL). Towuti , 02°41.335'S, 121°25.897'E; F. Herder & A. Nolte 29 November 2002: ZFMK 44928–44931 , 4 ex. (females, 61.2–65.6 mm SL). Towuti, Timampu, fish market: Catch of commercial fishermen collecting small fishes in the pelagic areas of L. Towuti; F. Herder 15 April 2004: ZFMK 44936–44937 , 2 ex. (females, 73–75.7 mm SL). – Nomorhamphus weberi Indonesia, Sulawesi Selatan: Lake Matano , 02°30.149'S, 121°19.416'E; F. Herder October 2002: ZFMK 44924–44927 and 44932–44935, 8 ex. (females, 64.1–73.4 mm SL).

Figures

Fig. 8. A, B, Nomorhamphus sagittarius; Indonesia, Sulawesi: Sulawesi Tenggara; Mangolo River, 03°58'56.6"S 121°34'05.5"E (© R. K. Hadiaty). A, male; B, male, immediately after catching.

Fig. 9. A, Nomorhamphus sagittarius, MZB 21301, holotype, 42.8 mm SL, male; B, MZB 21302, paratype, 72.5 mm SL, female.

Fig. 10. Radiograph of Nomorhamphus Sagittarius: A, MZB 21301, holotype, 42.8 mm SL, male; B, MZB 21302, paratype, 72.5 mm SL, female.

Fig. 12. Diagrammatic representation of the caudal skeleton of Nomorhamphus sagittarius, MZB 21301, holotype, 42.8 mm SL, male. Scale bar = 500 μm. EP, Epural; HY, Hypural.

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. 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.11. Mangolo River, type locality of Nomorhamphus sagittarius (© R. K. Hadiaty).