Belobranchus belobranchus (Valenciennes, 1837)

Afrisal, Muhammad, Nurjirana, Nurjirana, Haryono, Haryono, Mokodongan, Daniel Frikli, Wibowo, Kunto, Moore, Abigail Mary & Hubert, Nicolas, 2025, Revised diagnoses of the gudgeons Belobranchus belobranchus and B. segura (Actinopterygii, Gobiiformes, Eleotridae), ZooKeys 1232, pp. 173-186 : 173-186

Belobranchus belobranchus (Valenciennes, 1837)

Figs 1 , 2 , 3 A – D , 5 A , 6 , Tables 1 , 2 English name: Throat-spine Gudgeon

Eleotris belobrancha Valenciennes in Cuvier and Valenciennes 1837: 243 (type locality: Manado Island, Sulawesi, Indonesia)

Belobranchus quoyi Bleeker, 1856: 300 (type locality: Manado Island, Sulawesi, Indonesia)

Belobranchus taeniopterus Bleeker, 1856: 301 (type locality: Boleling, Bali, Indonesia)

Material examined.

Non-type specimens. 94 specimens, all specimens from Indonesia. Java: • MZB.16307 , 84.6 mm SL, male, Cibareno , Pasir Baru, Cisolok, Sukabumi, Jawa Barat, S. Sauri et al., 23 Jun. 2002 • MZB.16328 , 63.1 mm SL, female, Cilumajan , Pasir Baru, Cisolok, Sukabumi, Jawa Barat, S. Sauri et al., 24 May 2002 • MZB.26872 [ex BIF.01651 ], 71.7 mm SL, male, Cibareno , Lebak, Banten, 6°57'48.0"S, 105°23'42.0"E, N. Hubert et al., 10 Dec. 2013 • MZB.26873 [ex BIF.1696 ], 77.5, female, MZB.26906 [ex BIF 01694 ], 58.7 mm SL, male, Citiis , Sukabumi, Jawa Barat, 6°56'46.0"S, 106°26'45.6"E, N. Hubert et al., 11 Dec. 2013 • MZB.23934 , 33.9 mm SL, male, Purworejo , Jawa Tengah, R. Hadiaty, 10 Sep. 2017 . Bali: • MZB.26874 [ex BIF.2385 ], 74.8 mm SL, male, MZB.26907 [ex BIF.2384 ], 65.0 mm SL, female, Nbang , Jembrana, Bali, 8°22'01.2"S, 114°45'07.2"E, N. Hubert et al., 15 Apr. 2014 . Sulawesi: • MZB.4795 , 67.4–106.9 mm SL, 2 specimens, male and female, Watu Songu , Ulubongka, Poso, Sulawesi Tengah, Suyanto, 10 Nov. 1982 • MZB.11665 , 70.1–108.6 mm SL, 3, 1 male, 2 females, MZB.11676 , Lambuno , Wana Mukti, Mountong, Donggala, Sulawesi Tengah, Agus, 3 May 2002 • MZB.11715 , 45.4–52.1 mm SL, 6 specimens, 2 males, 4 females, Haryono and A. Munim, 8 Aug. 2001 • MZB.11731 , 66.1–100.2 mm SL, 8 specimens, 2 males, 6 females, Wapo river , Lombongo, Suwawa, Gorontalo, Haryono and A. Munim, 7 Aug. 2001 • MZB.11735 , 57.3–65.2 mm SL, 4 specimens, 3 males, 1 female, Tolumolu , Kota Selatan, Sulawesi Utara, 8 Aug. 2001 • MZB.11964 , 109.5 mm SL, female, MZB.11975 , 113.0 mm SL, female, MZB.12048 , 62.3 mm SL, female, Bolaang Mongondow , Sulawesi Utara, Haryono and Hesron, 21–26 May 2002 • MZB.20004 , 58.6–77.1 mm SL, 3 specimens, 1 male, 2 females, Masembo , Mekongga , Tinukari, Wawo, Kolaka Utara, Sulawesi Tenggara, Jumaring, 30 Nov. 2010 • MZB.20352 , 36.4–115.4 mm SL, 17 specimens, 11 males, 6 females, MZB.20381 , 52.9–96.2 mm SL, 9 specimens, 5 males, 4 females, MZB.20391 , 78.9 mm SL, female, MZB.20398 , 107.0– 129.5 mm SL, 3 specimens, 2 males, 1 female, MZB.20406 , 58.5–63.8 mm SL, 3 specimens, 1 male, 2 females, MZB.20415 , 51.0– 100.3 mm SL, 3 males, Tinukari , Wawo, Kolaka Utara, Sulawesi Tenggara, R. Hadiaty et al., 28 Jun. – 3 Jul. 2011 • MZB.22703 , 84.1 mm SL, male, Bonepuso , Bulagi Selatan, Banggai Kepulauan, S. Sauri, 20 Sep. 2014 • MZB.24579 , 101.4 mm SL, male, Marinding , Luwu, Sulawesi Selatan, 3°21'43.5"S, 120°15'54.3"E, seine net, D. Lumbantobing, 12 Aug. 2016 . Alor: • MZB.5346 , 115.3 mm SL, male, Alor , Nusa Tenggara Timur, Sudarmanu, Apr. 1984 . Halmahera : • MZB.18812 , 85.3 mm SL, male, MZB.18830 , 61.3–79.7 mm SL, 3 males, MZB.21174 , 32.8 mm SL, male, MZB.21184 , 93.4 mm SL, female, MZB.21209 , 71.8–98.4 mm SL, 5 specimens, 1 male, 4 females, MZB.21219 , 58.2 mm SL, female, MZB.26661 [ex MZB.18747 ], 63.3–130.7 mm SL, 7 specimens, 1 male, 6 females, MZB.26662 [ex MZB.18820 ], 71.8 mm SL, female, Ake Jira, Weda Tengah, R. Hadiaty et al., 4 Feb. 2010 – 16 Jul. 2011 . Papua: • MZB.15631 , 95.2 mm SL, female, Waigeo , Raja Ampat, Papua, R. Hadiaty et al., 4 Jun. 2007 • MZB.17098 , 65.3–97.6 mm SL, 2 males, MZB.17118 , 59.7–61.0 mm SL, male and female, MZB.17140 , 91.9 mm SL, male, Batanta , Raja Ampat, Papua Barat, R. Hadiaty et al., 30 July – 5 May 2008 .

Diagnosis.

A species of Belobranchus with the following combination of characters: head relatively depressed; interorbital width 4.8–8.0 % (mean 6.0 %) of SL; jaw length 10.3–16.7 % (14.1 %) of SL; caudal-peduncle depth 11.9–15.0 % (13.6 %) of SL; body with 3 dark-brown bands seaparated by pale bands, with many dark horizontal lines (one per scale row) along lateral surface; dorsal and lateral surfaces of head with many small whitish spots; 1 or 2 distinct oblique brown lines extending from eye to posterior edge of operculum (not always visible); first dorsal fin typically uniformly mottled dark brown or with thin yellowish distal edge; largest recorded specimen 130.7 mm SL.

Distribution and habitat.

Belobranchus belobranchus has been recorded from the South China Sea ( Randall and Lim 2000), Indonesia: Java, Bali, Lombok, Flores, Alor, Timor, Buton, Sulawesi, and Halmahera islands, and West Papua ( Roberts 1993; Tjakrawidjaja 2002; Larson and Pidgeon 2004; Larson et al. 2007; Keith et al. 2012; Tweedley et al. 2013; Dahruddin et al. 2016; Miesen et al. 2016; this study); the Philippines ( Jamandre 2023); Japan ( Sakai et al. 2001; Nakabo 2002); Papua New Guinea ( Fricke et al. 2014; Amick and Toko 2021) (Fig. 6 ). Belobranchus belobranchus is an amphidromous species, characterized by migration between freshwater and coastal environments ( Keith et al. 2012; Sahami et al. 2019); its habitat predominantly encompasses the lower regions of rivers, typically at altitudes to 5 m, and it has been observed in muddy to clear river systems featuring sandy to rocky or gravel bottoms ( Parenti 2021). Like most eleotrids, this fish is carnivorous ( Kiruba-Sankar et al. 2018).

Figures

Figure 1. Neighbor-join phylogenetic tree of COI GenBank accessions for the genus Belobranchus [Kimura 2 - Parameter model (K 2 P); 1000 bootstrap replications; Eleotris fusca as outgroup].

Figure 2. Morphometric relationships in Belobranchus belobranchus (circles) and B. segura (triangles) A interorbital width B jaw length C caudal-peduncle depth.

Figure 3. Fresh specimens of Belobranchus species A – D B. belobranchus A MZB. 26873, 77.5 mm SL B MZB. 26907, 74.8 mm SL C MZB. 26872, 71.7 mm SL D MZB. 26906, 58.7 mm SL) E – H B. segura E MZB. 26902, 68.9 mm SL F MZB. 26687, 59.6 mm SL G MZB. 26668, 56.3 mm SL H MZB. 26894, 52.6 mm SL.

Figure 5. Schematic illustration of the number and patterns of lines on the cheek and lateral bands on the body of Belobranchus species A B. belobranchus B B. segura.

Figure 6. Distributional records of B. belobranchus (circles) and B. segura (triangles) based on collected specimens examined in this study.