Butis huberti, Keith & Mennesson, 2023

Keith, Philippe & Mennesson, Marion I., 2023, Review of Butis (Teleostei: Butidae) from Indo-Pacific islands with description of three new species, Cybium 47 (4), pp. 431-466 : 457-458

Butis huberti n. sp.

( Figs 1-3A , 13 ; Tables III-IV)

Material examined

Holotype: MNHN 2001-3146 , male (89 mm SL), Vietnam, Tra Vinh, 12 May 1996, Bouchereau coll.

Paratype: BMNH 1894.1 .19.31, female (101.3 mm SL), Malaysia, Sarawak, Borneo , 1894, Brooke don .

Diagnosis

Interorbital space with scales (2-3/9-10/2-3) ( Fig. 1a 5 ); jaws reaching back to middle of eye ( Fig. 1b 1 ); auxiliary scales on body ( Fig. 1c 2 ); body depth at anal fin origin 21-23% SL and at first dorsal fin 22-26%; caudal peduncle depth 13-14% SL.

Description

The scale counts are given in Table III and selected morphometrics in Table IV. Below, the holotype counts are given first, followed in brackets, if different, by the paratype counts. The body is high, the body depth at anal fin origin is 23(21)% SL, at first dorsal fin 26(22)% SL, and the caudal peduncle depth is 14(13)% SL. Predorsal length 45(47)% SL and preanal length 60% SL. Serrated bony ridges on the head (26 medium spines) and snout (12-20 spines). Size: 89 mm SL.

The head 37(38)% SL is depressed as is the snout; snout length 13(12)% SL. Mouth terminal, lower jaw prominent, jaws 16(17)% SL reaching back to middle of eye. Outermost row of teeth in upper and lower jaw smaller in size than innermost row. Innermost row with caniniform teeth in both jaws. Interorbital width 10% SL. Gill opening below rear edge of eye ( Fig. 1b 2 ).

Dorsal fins VI-I,8 with no filamentous rays; first dorsal fin triangular. Anal fin I,8 directly opposite to the second dorsal fin. Pectoral fins 20(18) with the posterior margin slightly rounded. The caudal fin is with 12 branched-rays and its posterior margin is rounded. Pelvic fins separate, I,5.

Lateral scales 27, with ctenoid scales on flanks, opercle, cheeks, belly and caudal peduncle. Scales in transverse back series 11(10), in transverse forward 16, in predorsal 38(45) and in zigzag 6. Interopercle scaled. Small ctenoid scales on the head between orbital ridge and eyes, IOS 2-3/9-10/2-3 ( Fig. 1a 5 ) (+2-3 rows of scales directly on eye on holotype). Scales extending onto anterior part of snout. Breast with ctenoid scales. Pectoral base scales ctenoid. Scales on cheek (SCH) 7-8. Auxiliary scales on body, 1-5 per scale (usually one on the anterior part of body, 5 on the posterior part) ( Fig. 1c 2 ); Auxiliary scales also on head, predorsal area and cheeks. Head pores present, with pores A’, B, C, D, E, F, H, I, J, K, L’; 5 preopercular pores (M’, N, O, P, Q’).

Male with an elongated urogenital papilla with distal tip rounded. Female has a rectangular or chalice-shaped bulbous urogenital papilla with crenulated outer edges around distal opening.

Colour in preservation ( Fig. 13 )

Head and body dark brown. Pectoral fins beige to translucent, base brown with a large black spot at the centre. Abdomen and gular region dark brown. Anal and second dorsal fins dark spotted with white spots aligned on rays. Caudal fin blackish. Pelvic fins dark brown.

Colour in life Unknown.

Ecology

This species occurs in streams in brackish to fresh waters and estuaries.

Distribution

This species is currently known from Vietnam and Borneo ( Fig. 3A ).

Etymology

The new species is dedicated to our colleague Nicolas Hubert, from the French National Research Institute for Sustainable Development (IRD), in recognition of his work on the freshwater fauna of South Asia and Indonesia.

Comparison

Butis huberti differs from B. koilomatodon , B. delagoensis and B. gymnopomus in having 9-10 scales versus 0 between the two orbital ridges, and predorsal scales 38-45 versus 12-16. It differs from B. prismaticus , B. amboinensis , B. butis and B. abdoui in having jaws reaching back to 1/3 or middle of eye versus jaws reaching back to below front part of eye. It differs from B. humeralis in having a body depth at first dorsal fin 22-26% versus 19-22% SL, caudal peduncle depth 13-14% versus 11-13% SL, and body depth at anal fin origin 21-23% versus 18-21% SL. It differs from B. audebertae in having IOS 2-3/9-10/2-3 versus 1-2/3-7/ 1-2, a body depth at first dorsal fin 22-26% versus 16-19% SL and caudal peduncle depth 13-14% versus 9-11% SL.

Figures

Figure 1. – A: The different patterns of interorbital scales (IOS); head in dorsal view. B: Size of the jaw; head in lateral view. C: Auxiliary scales on flanks.

Figure 2 (see also following page). – A: Bayesian tree of the cytochrome c oxidase subunit (COI; 452 bp) for sequenced specimens of Butis. Numbers at each node represent posterior probabilities. B: Barcoding NJ K2P tree of the COI gene (196 bp) for sequenced specimens of Butis including the holotype of Butis humeralis from the MNHN collection. Numbers at each node represent bootstrap values. C, D: Barcoding NJ K2P trees of the 12S and the 16S genes (129 and 270 bp respectively) for sequenced specimens of Butis collected during the 19th century from the MNHN collection including a paratype of B. audebertae (MNHN A-1503). Numbers at each node represent bootstrap values. [A high resolution version is available online.]

Figure 3. – A, B: Distribution of Butis species.

Figure 5. – A: Butis butis, MNHN 2022-0233, neotype (male, 55.2 mm SL), India (Photo P. Keith); B: Butis butis, Hamilton’s original, unpublished illustration (from Britz, 2019); C: Butis butis, Fly River, Papua New Guinea (Photo G. Allen); D: Butis butis, MNHN 2022-0213 (male, 95 mm SL), Solomon, tag 17612 (Photo P. Keith).

Figure 13. – Butis huberti n. sp., holotype, MNHN 2001-3146 (male, 89 mm SL), Vietnam (Photo P. Keith).