Tor dongnaiensis, Hoàng, Ức, Ạm, Ạnh Ph, Durand, Jean-Dominique, Ần, Ngân Tr Ọng Tr & Phan, Phúc Đình, 2015

Hoàng, Ức, Ạm, Ạnh Ph, Durand, Jean-Dominique, Ần, Ngân Tr Ọng Tr & Phan, Phúc Đình, 2015, Mahseers genera To r and Neolissochilus (Teleostei: Cyprinidae) from southern Vietnam, Zootaxa 4006 (3), pp. 551-568 : 556-560

Tor dongnaiensis sp. nov.

Holotype: UNS 00859, 240 mm SL; middle Đồng Nai drainage: Cát Tiên National Park, Lâm Đồng Province, Vietnam (11°26’33.32” N 107°26’4.01” E, 162 m), 7 March 2014, Hoàng Đức Huy, Ph ạm Mạnh Hùng and Tr ần Tr ọng Ngân ( Fig. 2 ).

Paratypes (all same locality as holotype): ZRC 54628, 114 mm SL, 11 March 2014; UNS 00861, 167 mm SL, 12 March 2014; UNS 00862, 201 mm SL, 9 April 2014; ZRC 54627, 243 mm SL, 26 October 2013; UNS 00880, 167 mm SL, 1 June 2014; UNS 00888, 189 mm SL, 23 October 2014; UNS 00889, 411 mm SL, 23 October 2014 (11°39’20.8” N 107°16’04.7” E, 195 m).

Diagnosis. Tor dongnaiensis most closely resembles T. tambroides but differs in having a yellow to grey vs. silver-bronze and reddish body, transverse scale rows 4/1/2 vs. 3/1/2, predorsal scales 10 vs. 8-9, pelvic-fin rays 1/ 8 vs. 2/8, median projection in upper lip absent vs. present, and caudal fin lobes unequal vs. equal. Tor dongnaiensis differs from T. ater in having lateral scales 23–24 vs. 30–31, transverse scale rows 4/1/2 vs. 5/1/2, predorsal scales 10 vs. 11–12, median lobe in lower lip long vs. short, stripe along side of body absent vs. present. Tor dongnaiensis differs from T. laterivittatus and T. sinensis in having transverse scale rows 4/1/2 vs. 3–4/1/2, stripe along side of body absent vs. present. Tor dongnaiensis differs from T. yingjiangensis in having deeper body 28.3–33.6 vs. 25.5–27.3% SL, caudal peduncle length 18.4–22.3 vs. 11.3–14.8% SL, and median lobe in lower lip long vs. short. Tor dongnaiensis differs from T. tambra in having transverse scale rows 4/1/2 vs. 3/1/2, predorsal scales 10 vs. 8–9, lips thickened vs. normal, and median lobe in lower lip long vs. short.

Description. General appearance in Figure 3 ; meristic and morphometric data of specimens given in Table 3 . Head conical, longer than deep, its depth 1.3–1.5 times in HL. Snout slightly pointed. Mouth subterminal and oblique, its posterior edge not extending to vertical line of orbit. Rostral hood straight and pointed. Lips thick fleshy; upper lip rolled backwards and upwards without median projection; median lobe of lower lip long, more or less square and reaching an imaginary line between the corners of the mouth ( Fig. 4 e, f). Rostral and maxillary barbels almost equal in length and both longer than eye diameter.

Body elongate, moderately compressed, its depth about 3.0–3.5 times in SL; caudal peduncle about 1.5–1.8 times longer than deep. Dorsal body profile convex, ventral profile rounded. Lateral line complete, 23–24 scales; 10 predorsal scales; 4/1/2 scales in transverse row anterior to pelvic-fin insertion.

Tor dongnaiensis Tor mekongensis Dorsal with 4 simple and 9 branched rays, last simple ray smooth; dorsal-fin origin inserted approximately opposite to pelvic-fin origin; distal margin slightly concave. Pectoral fin pointed with 1 simple and 16 branched rays. Pelvic fin pointed, with 1 simple and 8 branched rays; axillary scale present. Anus immediately in front of anal fin. Anal fin pointed with 3 simple and 6 branched rays. Caudal deeply forked with 10+9 principal rays, 9+8 being branched and upper lobe smaller than lower one.

Colour in life. Head dark yellowish turquoise on back, yellowish turquoise around orbit and on side, white on opercula and lower jaw. Body dark grey on back, light yellow above lateral line, grey white on belly. Scales light yellow to silver white, black at scale bases. All fins dark grey with yellow tinge on the branched rays. In sub-adult specimens, scales and fins light yellow but pectoral fin and pelvic fin pinkish orange on coastal rays. In juvenile specimens, scales bluish silver; dorsal and caudal fins greenish yellow, dark bold on rays; pectoral fins pinkish orange; pelvic and anal fins yellow with orange at coastal rays and hyaline on distal parts ( Fig. 3 a, b, c).

Colour in preservative. Body including head dark grey on back. Opercula becoming black at base. Lower half of body greyish white. All fins grey to dark grey ( Fig. 3 d).

Etymology. Specific epithet is in reference to the type locality of Đồng Nai drainage.

Suggested common name. Cá ngựa xám Đồng Nai (Vietnamese), Dongnai mahseer (English).

Figures

FIGURE 2. Type localities of Tor mekongensis (black star) and T. dongnaiensis (white star), and collection localities of T. sinensis (black triangle), and Neolissochilus stracheyi (white cross).

FIGURE 3. Tor dongnaiensis: (a) juvenile paratype (ZRC 54628, 114 mm SL), (b) sub-adult paratype (UNS 00880, 167 mm SL), (c) adult holotype (UNS 00859, 240 mm SL) in life, and (d) in preservative; lateral views. Scale 10 mm.

FIGURE 4. Head of Tor sinensis UNS 00873, 205 mm SL (a, c) front view, (b, d) ventral view; T. dongnaiensis holotype UNS 00859, 240 mm SL (e) front view, (f) ventral view; T. mekongensis holotype UNS 00877, 337 mm SL (g) front view, (h) ventral view; Neolissochilus stracheyi Tor - like morph UNS 00949, 428 mm SL (i) front view, (k) ventral view; Neolissochilus stracheyi Neolissochilus - like morph UNS 00872, 308 mm SL (l) front view, (m) ventral view. Scale 10 mm.

Tables

TABLE 3. Morphometric and meristic characters of Tor dongnaiensis sp. nov. and Tor mekongensis sp. nov.

	Holotype	Range	Mean±SD	N	Holotype	Range	Mean±SD	N
SL (mm)	240	11.4–41.1	21.6±8.9	8	337	7.6–33.7	16.4±15.0	3
Morphometrics
% SL
Head length	24.2	24.2–28.1	25.8±1.4	8	25.5	25.5–28.9	27.8±2.0	3
Depth of body	28.3	28.3–33.6	31.1±1.7	8	27.6	27.6–30.2	28.9±1.3	3
Body width at dorsal-fin origin	15.4	14.9–20.1	16.4±1.7	8	13.6	13.6–15.8	14.4±1.2	3
Predorsal length	51.5	50.8–53.5	51.7±1	8	50.4	50.4–52.2	51.3±0.9	3
Prepectoral length	25.1	23.5–27.4	25.6±1.2	8	24.6	24.6–27.7	26.2±1.5	3
Prepelvic length	51.7	46.9–54.5	50.9±2.2	8	48.4	48.4–52.8	50.8±2.3	3
Preanal length	75.0	74.1–85.2	76.5±3.7	8	74.2	74.2–76.3	74.9±1.2	3
Distance between pectoral- and pelvic-fin origins	23.8	21.1–24	22.5±1.1	8	20.5	20.1–21.1	20.6±0.5	3
Distance between pelvic- and anal-fin origins	20.4	17.5–22.6	20.1±1.6	8	20.5	19.5–20.5	19.9±0.5	3
Depth of caudal peduncle	11.9	11.3–13.5	12.3±0.6	8	11.3	11.3–13.2	12.3±1.0	3
Length of caudal peduncle	19.6	18.4–22.3	20.3±1.3	8	21.4	18.9–21.4	20.0±1.3	3
Length of dorsal fin	22.1	17.5–26.3	23.3±2.6	8	21.4	21.4–27.0	24.9±3.1	3
Length of dorsal-fin base	12.9	12.9–15.8	14.3±0.9	8	13.6	13.6–15.1	14.4±0.7	3
Length of pectoral fin	20.8	19.7–23.5	21.7±1.2	8	20.2	20.2–22.4	21.5±1.2	3
Length of pelvic fin	19.2	18.9–20.9	19.5±0.7	8	17.5	17.5–18.9	18.3±0.7	3
Length of anal fin	19.6	19.3–22.2	20.5±1.2	8	21.5	20.1–22.4	21.3±1.1	3
Length of anal-fin base	7.1	7.1–8.6	7.7±0.5	8	6.8	6.8–20.4	11.6±7.6	3
% HL
Head depth	72.4	68.2–79	72±3.9	8	65.1	65.1–69.6	67.6±2.3	3
Head depth at eye	55.2	50–58.5	54.2±2.9	8	53.5	52.2–54.5	53.4±1.2	3
Maximum head width	59.5	53.1–77.3	58.8±7.7	8	58.1	52.2–58.1	55.3±3.0	3
Snout length	39.7	33.3–39.7	36.1±2.5	8	32.6	30.4–32.6	31.6±1.1	3
Interorbital width	43.1	31.3–49.2	39.6±5.3	8	44.2	28.3–44.2	36.3±8.0	3
Eye diameter	19.0	15.9–22.2	19.4±1.9	8	17.4	17.4–26.1	22.1±4.4	3
Mouth width	25.9	22.4–31.9	26.3±3.2	8	25.6	25.6–27.3	26.3±0.9	3
Counts
Lateral-line scales	24	23–24	23.4±0.5	8	23	23	23.0±0.0	3
Scales between lateral line and origin of dorsal fin	4	4	4.0±0.0	8	3	3	3.0±0.0	3
Scales between lateral line and origin of pelvic fin	2	2	2.0±0.0	8	2	2	2.0±0.0	3
Scales between lateral line and origin of anal fin	3	3	3.0±0.0	8	3	3	3.0±0.0	3
Circumpeduncular scales	12	12	12.0±0.0	8	12	12	12.0±0.0	3
Predorsal scales	10	10	10.0±0.0	8	9	9	9.0±0.0	3