Melanotaenia susii, Nugraha & Kadarusman & Hubert & Avarre & Hadiaty & Slembrouck & Carman & Sudarto & Ogistira & Pouyaud, 2015

Nugraha, Media Fitri Isma, Kadarusman, Hubert, Nicolas, Avarre, Jean-Christophe, Hadiaty, Renny K., Slembouck, Jacques, Carman, Odang, Sudarto, Ogistira, Ran & Pouyaud, Laurent, 2015, Eight new species of Rainbowfishes (Melanotaeniidae) from the Birds Head Region, West Papua, Indonesia, Cybium 39 (2), pp. 99-130 : 114-116

Melanotaenia susii , sp. nov.

Kadarusman, Hubert & Pouyaud

(Figs 15, 16; Tab. IX)

Diagnosis

Melanotaenia susii is distinguished from all of its congeners in the Birds Head region by: dorsal rays IV to VI + I,13 to 16; anal rays I, 23 to 27; lateral scales 38 to 39; transverse scales 10 to 11; predorsal scales 17 to 20; cheek scales 16 to 20; total gillrakers on first arch 19; a compressed body with a long snout length, 9.2-10.2% of SL; a thin interorbital width, 8.0-8.4% of SL; a long predorsal length, 50.4-52.2% of SL; a short pectoral fin length, 17.6-19.0% of SL; a long pelvic fin length, 19.8-24.4% of SL; a long spine length on first dorsal fin, 11.4-12.4% of SL; a moderately long dorsal fin base length, 37.2-39.0% of SL; a long anal fin base length, 41.1- 45.6% of SL; a marked red margin stripe on dorsal fins; 2-5 vertical bars extending across the entire body depth; dorsal fin origin vertically projected behind anal origin, between 3 rd and 5th anal soft ray. front of upper jaw in about 6-7 irregular rows, reduced to 2 rows posteriorly; teeth at front of lower jaws in about 9-11 irregular rows, reduced to 2 rows posteriorly; small conical teeth on vomer and palatines.

Scale of body large, cycloid, crenulated, arranged in regular horizontal rows; predorsal scales extending to posterior margin of interorbital; 3 rows of preopercle scales. First dorsal fin origin projected behind anal origin, between 3 rd and 5 th anal soft ray; tip of first dorsal fin reaching base of 3 rd to 5 th soft ray of second dorsal fin; tip of second dorsal fin reaching ¾ of caudal peduncle in females and ¾ to hypural junction in males; tip of anal fin reaching ¹/³ to half of caudal peduncle in females and half to ¾ of caudal peduncle in males; pelvic fin tips reaching base of 3 rd to 7 th anal soft ray; caudal fin moderately forked.

Colour of freshly collected male specimens: variable from green olive to intense black dorsally; lateral flanks with mauve reflections on upper half and reddish on lower half; a discontinuous midlateral dark green olive stripe with 1 scale row in middle part of body and 2 scale rows on caudal peduncle; 2-5 dark olive green vertical bars on anterior body region with 1-6 scales width and extending from dorsal to ventral edges; pectoral fin translucent with black rays; pelvic fin reddish black; anal fin overall dark with blue rays and with a reddish posterior tip; dorsal fins black with a marked red margin. Colour pattern of females similar, but less vivid than males.

Sexual dimorphism: males are slightly deeper bodied than females (33.6-39.9 vs 31.0-37.0% SL) and have second dorsal and anal fins more elongated posteriorly.

Comparisons

Melanotaenia susii belongs to the “Central Ayamaru Plateau” group of species, together with M. fasinensis , M. ericrobertsi , M. boesemani , M. ajamaruensis , M. klasioensis sp. nov. and M. longispina sp. nov. ( Fig. 2 ). The new species differs from all of these species by the genetic polymorphism assessed from the 12 microsatellite loci ( Figs 3 , 7 ).

Melanotaenia susii differs from M. fasinensis by the coloration pattern (presence of 2-5 vertical bars on anterior body region vs absent), more transversal scales (10-11 vs 9), a longer predorsal length (50.4-52.2 vs 48.1-49.8% SL), a longer pelvic fin length (19.8-24.4 vs 17.0-19.5% SL) and a shorter dorsal fin base length (37.2-39.0 vs 39.0-42.2% SL).

The new species differs from M. ajamaruensis and M. boesemani by a longer snout length (9.2-10.2 vs 7.2-8.7% SL), a longer pelvic fin length (19.8-24.4 vs 13.8-18.2% SL), a longer anal fin base length (41.1-45.6 vs 32.2-40.4% SL), more transverse scales (10-11 vs 7-8), more lateral scales (38-39 vs 33-37) and more predorsal scales (17-20 vs 15-16).

Following Allen et al. (2014b), Melanotaenia susii can be distinguished from M. ericrobertsi and M. laticlavia by the position of the first dorsal fin origin compared to the anal fin origin (dorsal fin origin behind anal origin, between 3 rd and 5 th anal soft ray vs dorsal fin origin about equal with anal fin origin), and the pattern of body coloration (presence of vertical bars on anterior body region vs absent). Melanotaenia susii differs from M. laticlavia by more lateral scales (38-39 vs 36-37) and more gillrakers (19 vs 16-17). It differs from M. ericrobertsi by more cheek scales (16-20 vs 12-16).

Melanotaenia susii differs from M. longispina sp. nov. by the presence of a dorsal margin stripe (vs absent), shorter spines on first dorsal, second dorsal and anal fins (11.4-12.4 vs 13.1-15.3, 8.2-11.6 vs 12.4-15.7, 7.6-9.7 vs 10.1-11.3% SL, respectively), a longer dorsal fin base length (37.2-39.0 vs 33.4-36.5% SL), and a longer second dorsal fin base length (23.9-26.6 vs 20.2-22.6% SL).

Melanotaenia susii differs from M. klasioensis sp. nov. by more lateral scales (38-39 vs 36-37), a longer snout length (9.2-10.2 vs 8.6-9.1% SL), a narrower interorbital width (8.0-8.4 vs 8.6-9.2% SL), a narrower body width (12.7-14.1 vs 14.2-15.8% SL), a longer predorsal length (50.4-52.2 vs 49.4-50.2% SL), a shorter pectoral fin length (17.6-19.0 vs 20.1-20.7% SL), and a longer spine length on first dorsal fin (11.4-12.4 vs 10.4-10.9% SL).

Distribution and habitat

The new species is currently known from Susi Creek, a karst resurgence of less than 3 m width with a course of a few kilometres before disappearing in a subterranean outlet ( Fig. 1 ). The habitat at the type locality ( Fig. 17 ) consists of clear, shallow and slow flowing water. The creek flows over limestone boulder and muddy bottom with many dead tree branches and is bordered by dense forest .

Physical water parameters at the type locality on May 2007 were: water temperature 26.0°C; pH 7.7; conductivity 330 µS. Chemical parameters (in mg/L): K: 0.01; Ca: 45.70; Mg: 2.17; Na: 0.27; Mn: 0.00; PO4 : 0.09; SO4: 0.49; HCO3 : 181; CO3: 0.0; Cl: 2.07; Cd: 0.0; Ni: 0.03 .

Etymology

The species is named susii , with reference to the creek name at the type locality.

Figures

Figure 1. - Type localities of the 24 valid Melanotaenia species and the eight new species from the Birds Head region

Figure 2. - Maximum likelihood tree for Birds Head region Melanotaenia species based on analysis of partial COI sequences (650 bp). Bootstrap values obtained for ML on 500 replicates and for NJ (within brackets).

Figure 3. - Factorial correspondence analysis of genotypes (255 individuals; 12 loci) from all the species belonging to the phyloge- netic cluster “Central Ayamaru Plateau” and to M. arfakensis. Projection on axis 2 and axis 4 segregating the new species M. klasioensis, M. longispina and M. susii with other species.

Figure 7. - Factorial correspondence analysis of genotypes (164 individuals; 12 loci) from the five new species belonging to COI “Northern Birds Head” clade. Projection on axis 1 and axis 2 segregating the five new species M. klasioensis, M. longispina, M. manibuii, M. sembrae and M. susii.

Figure 17. - Type locality of Melanotaenia susii, Susi Creek, Sorong Selatan, West Papua, Indonesia. Figure 18. - Melanotaenia sembrae, MZB 22158 (holotype), male, 87.3 mm SL, Sembra River near Teminabuan, Sorong Selatan, West Papua, Indonesia. Figure 19. - Melanotaenia sembrae, a female, 85 mm SL, same data as for holotype. Figure 20. - Melanotaenia manibuii, MZB 22166 (holotype), male, 103.7 mm SL, Tisbo River near Bintuni, West Papua, Indonesia. Figure 21. - Melanotaenia naramasae, MZB 22160 (holotype), male, 99.1 mm SL, Naramasa River, Birds Neck Isthmus Figure 22. - Melanotaenia naramasae, MZB 22161 (paratype), female, 75.9 mm SL, same data as for holotype. Figure 23. - Type locality of Melanotaenia naramasae, Naramasa River, Birds Neck, West Papua, Indonesia.