Research Article |
Corresponding author: Heok Hee Ng ( heokhee.ng@gmail.com ) Academic editor: Ralf Britz
© 2023 Heok Hee Ng, Maurice Kottelat.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ng HH, Kottelat M (2023) Mystus celator, a new species of catfish from northern Myanmar (Actinopterygii: Siluriformes: Bagridae). Vertebrate Zoology 73: 981-990. https://doi.org/10.3897/vz.73.e110875
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Abstract
Mystus celator sp. nov. is described from the Irrawaddy River drainage in northern Myanmar. It can be distinguished from congeners in having a combination of: three equally dark longitudinal stripes separated by two pale interspaces on sides of body; round, dark tympanic spot; ovoid, dark spot on caudal peduncle; length of adipose-fin base 18.0–23.3% SL; angle of predorsal profile 21–24°; posterior cranial fontanelle not reaching base of supraoccipital process; 25–30 rakers on the first branchial arch; and 35–36 vertebrae. The identity of Mystus pulcher is fixed with the designation of a lectotype.
Freshwater fishes, Irrawaddy River, Teleostei
The bagrid catfish genus Mystus Scopoli, 1777 consists of nearly 50 species (
Measurements were made point to point with digital calipers and data recorded to tenths of a millimeter. Counts and measurements were made on the left side of specimens whenever possible, following
Mystus pulcher (in part) –
MHNG 2790.082, 80.6 mm SL; Myanmar: Kachin State: Thein Lin Chaung at Thein Lin village, E of Bhamo, 24°11′1″N 97°15′30″E; M. Kottelat and Nyein Chan, 24 June 2017.
CMK 26781 (1), 62.4 mm SL; Myanmar: Kachin State: Moe Sit Chaung, a small stream entering Irrawaddy River from the N opposite Shwegu, about 35 km downstream of Bhamo, about 1.5 km from mouth, ca. 100 masl, 24°12′35″N 96°50′5″E; Nyein Chan, 9 February 2017. CMK 26981 (1), 77.3 mm SL; ZRC 64887 (1), 74.5 mm SL; Myanmar: Kachin State: Nant Sa Ri Chaung at Kaung Jar Xan village, E of Bhamo, 24°12′33″N 97°15′35″E; M. Kottelat and Nyein Chan, 24 June 2017.
ZSI F4718/1 (1), 51.5 mm SL; ZSI F4719/1 (1), 51.4 mm SL; Myanmar: Bhamo; J. Coggin-Brown, 1909–1910 (photographs examined).
Mystus celator sp. nov. is distinguished from congeners except for M. pulcher and M. rufescens in having a combination of three equally dark longitudinal stripes separated by pale interspaces on the sides of the body, a round, dark tympanic spot, and an ovoid, dark spot on the caudal peduncle (vs. at least one of these three features absent; Table
Dark longitudinal stripes on body of equal intensity | Dark tympanic spot | Dark spot at extremity of caudal peduncle | |
M. albolineatus | + | — | + |
M. atrifasciatus | + | — | + |
M. bleekeri | + | + | — |
M. carcio | + | + | — |
M. celator sp. nov. | + | + | + |
M. cyrusi | + | — | — |
M. dibrugarensis | — | + | + |
M. multiradiatus | + | + | — |
M. mysticetus | + | + | — |
M. nanus | + | — | + |
M. ngasep | + | + | — |
M. pelusius | + | — | — |
M. pulcher | + | + | + |
M. prabini | — | + | + |
M. rhegma | + | — | — |
M. rufescens | + | + | + |
M. tengara | + | + | — |
M. vittatus | + | + | — |
Biometric data in Table
Holotype MHNG 2790.082 | Paratypes | Range | |||
CMK 26781 | ZRC 64887 | CMK 26981 | |||
Standard length (mm) | 80.5 | 62.4 | 74.5 | 77.3 | 62.4–80.5 |
% SL | |||||
Predorsal length | 40.4 | 41.2 | 39.1 | 39.6 | 39.1–41.2 |
Preanal length | 71.1 | 71.3 | 70.9 | 71.7 | 70.9–71.7 |
Prepelvic length | 55.2 | 55.4 | 58.4 | 57.2 | 55.2–58.4 |
Prepectoral length | 25.2 | 26.1 | 26.7 | 26.1 | 25.2–26.7 |
Length of dorsal-fin base | 17.3 | 18.9 | 15.4 | 15.7 | 15.4–18.9 |
Length of dorsal spine | 11.9 | 16.7 | 12.2 | 12.8 | 11.9–16.7 |
Length of anal-fin base | 11.1 | 13.5 | 12.8 | 13.5 | 11.1–13.5 |
Pelvic-fin length | 16.4 | 16.8 | 16.2 | 16.8 | 16.2–16.8 |
Pectoral-fin length | 19.3 | 23.1 | 20.0 | 19.4 | 19.3–23.1 |
Pectoral-spine length | 17.6 | 20.4 | 18.7 | 16.2 | 16.2–20.4 |
Caudal-fin length | 30.4 | 28.7 | 26.0 | 26.9 | 26.0–30.4 |
Length of adipose-fin base | 20.9 | 20.3 | 22.8 | 23.3 | 20.3–23.3 |
Dorsal to adipose distance | 12.5 | 8.5 | 10.6 | 8.9 | 8.5–12.5 |
Post-adipose distance | 14.2 | 14.7 | 14.1 | 15.3 | 14.1–15.3 |
Length of caudal peduncle | 18.4 | 16.1 | 16.9 | 17.5 | 16.1–18.4 |
Depth of caudal peduncle | 11.1 | 9.9 | 10.2 | 9.8 | 9.8–11.1 |
Body depth at anus | 20.7 | 21.5 | 23.1 | 21.0 | 20.7–23.1 |
Head length | 27.8 | 31.6 | 29.3 | 28.5 | 27.8–31.6 |
Head width | 20.1 | 19.4 | 20.7 | 19.7 | 19.4–20.7 |
Head depth | 18.9 | 19.7 | 19.3 | 19.8 | 18.9–19.8 |
% HL | |||||
Snout length | 35 | 33 | 34 | 37 | 33–37 |
Interorbital distance | 42 | 37 | 35 | 36 | 35–42 |
Eye diameter | 17 | 24 | 20 | 20 | 17–24 |
Nasal barbel length | 68 | 55 | 66 | 77 | 55–77 |
Maxillary barbel length | 261 | 290 | 273 | 295 | 261–295 |
Inner mandibular barbel length | 104 | 83 | 96 | 98 | 83–104 |
Outer mandibular barbel length | 150 | 189 | 136 | 144 | 136–189 |
Mouth subterminal, fleshy upper lip extending anteriorly beyond upper jaw. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary tooth band curved, of equal width throughout. Dentary tooth band much narrower than premaxillary tooth band at symphysis, tapering laterally. Vomerine tooth band unpaired, continuous across midline; smoothly arched along anterior margin; band width narrower than premaxillary band at midline, widening laterally and then tapering to a sharp point posterolaterally.
Barbels in four pairs. Maxillary barbel long and slender, extending to vertical through middle of anal-fin base. Nasal barbel slender, extending to midway between posterior orbital margin and dorsalmost point of gill opening. Inner mandibular-barbel origin close to midline; barbel thicker and longer than nasal barbel and extending beyond level of last pectoral-fin ray base. Outer mandibular barbel originating posterolateral of inner mandibular barbel, extending to two-thirds of distance between base of last pectoral-fin ray and pelvic-fin origin.
Body subterete, slightly compressed, becoming more so toward caudal peduncle. Dorsal profile rising evenly, not steeply, from tip of snout to origin of dorsal fin, sloping gently ventrad from origin of dorsal fin to end of caudal peduncle. Ventral profile slightly convex to anal-fin base, then sloping slightly dorsally to end of caudal peduncle. Skin smooth. Lateral line complete, midlateral in position. Vertebrae 19+16=35* (2) or 19+17=36 (2).
Dorsal fin with spinelet, spine, and 7 (4) rays. Origin of dorsal fin at about one-third of body. Dorsal-fin margin convex, with anterior branch of fin rays longer than other branches. Dorsal-fin spine moderately long, straight, slender, posterior edge with 4*–5 retrorse serrae. Nuchal plate triangular and narrow.
Pectoral fin with stout spine, sharply pointed at tip, and I,7* (2) or I,8 (2) rays. Anterior margin of spine smooth; posterior margin of spine with 11–15* large, retrorse serrae along entire length. Pectoral-fin margin straight anteriorly, convex posteriorly. Cleithral process in form of narrow triangle with concave dorsal margin and extending for half of pectoral-spine length.
Pelvic-fin origin at vertical through posterior end of dorsal-fin base, with i,5 (4) rays, its distal margin slightly convex; tip of adpressed fin just reaching anal-fin origin. Anus located at vertical through middle of adpressed pelvic fin; urogenital opening located immediately anterior to base of first anal-fin ray, at vertical through posterior quarter of adpressed pelvic fin. Males with an elongate conical genital papilla.
Adipose fin with convex margin for entire length, with deeply-incised posterior portion; adipose-fin base moderate, spanning nearly half of postdorsal distance. Anal-fin origin posterior to vertical through origin of adipose fin; anal fin with iii,5,i (1), iii,7* (1), iii,8,i (1), or iv,6,i (1) rays and convex distal margin.
Caudal peduncle moderately deep. Caudal fin deeply forked, with i,7,8,i (4) principal rays; both lobes acutely rounded, upper lobe more slender and longer than lower. Procurrent rays extending anterior to caudal-fin base.
Fixed in formalin, stored in 70% ethanol: Dorsal and lateral surfaces of head brown, fading to cream ventrally. Body predominantly brown on dorsal and lateral surfaces, fading to cream ventrally. Three brown longitudinal stripes on dorsal and lateral surfaces of body: dorsal stripe originating from supraoccipital and epiotic area, middle stripe originating from posterolateral corner of head, and ventral stripe originating from tip of cleithral process. All three stripes extending posteriorly to caudal-fin origin and separated by narrow, pale interspaces. Dark gray to black, round tympanic spot on body above cleithral process. Dark gray to black ovoid spot, about eye size, at mid-height of posterior extremity of caudal peduncle. Adipose fin largely hyaline, with brown melanophores scattered along base. All fins with hyaline interradial membranes and dusting of brown melanophores along fin rays. Nasal and maxillary barbels brown dorsally, cream ventrally. Mandibular barbels cream.
The specific name comes from the Latin noun celator, meaning a concealer or hider, and is used in allusion to its close similarity to (and misidentification with) M. pulcher.
Mystus pulcher was described from four syntypes collected from “…the district of Bhamo close to the Yunnan border” in the middle Irrawaddy River drainage (
Two congeners found sympatrically with M. celator sp. nov. in the Irrawaddy River drainage share with it a color pattern consisting of three equally dark longitudinal stripes separated by pale interspaces, a round dark tympanic spot and an ovoid, dark spot at the posterior extremity of the caudal peduncle: M. pulcher (Fig.
Lateral views of: a Mystus celator sp. nov., MHNG 2790.082, holotype, 80.6 mm SL; Myanmar: Irrawaddy River drainage, Thein Lin Chaung; b M. pulcher, CMK 28190, 79.0 mm SL; Myanmar: Irrawaddy River drainage, Watt Kya Chaung; c M. rufescens, CMK 17783, 89.0 mm SL; Myanmar: Ataran River drainage. Note difference in predorsal profiles and lengths of adipose-fin bases. Images not to scale.
Mystus ngasep (also from the Irrawaddy River drainage) also possesses three equally dark longitudinal stripes separated by two pale interspace stripes and a dark tympanic spot like M. celator sp. nov., but lacks the dark peduncular spot. It is additionally distinguished from M. celator sp. nov. in having a longer posterior cranial fontanel (reaching vs. not reaching base of supraoccipital process) and adipose-fin base (37.1–44.5% SL vs. 20.3–23.3), more vertebrae (40–41 vs. 35–36), and fewer rakers in the first branchial arch (16–19 vs. 25–30). Among the four remaining congeners known from the Irrawaddy River drainage (M. cineraceus, M. falcarius, M. gulio, and M. leucophasis), M. celator sp. nov. differs from all of them in having a color pattern of dark longitudinal stripes on the sides of the body separated by pale interspaces (vs. dark or silvery bodies without stripes) and a dark ovoid spot at the base of the caudal fin (vs. absent).
Two other congeners from the Brahmaputra River drainage (M. dibrugarensis and M. prabini) also possess dark longitudinal stripes as well as dark tympanic and peduncular spots. However, the color pattern of both M. dibrugarensis and M. prabini differ markedly from that of M. celator sp. nov. in having a middle stripe that is distinctly darker than the upper and lower stripes (vs. all three stripes of equal intensity). Mystus celator sp. nov. further differs from M. prabini in having a shorter adipose fin that does not contact (vs. contacting) the base of the last dorsal-fin ray (length of adipose-fin base 18.0–23.3% SL vs. 38.1–45.1), fewer vertebrae (35–36 vs. 39–40) and more rakers on the first branchial arch (25–30 vs. 10–12).
Although the distributions of M. celator sp. nov. and M. pulcher overlap, they have not been observed together at a single site. No habitat differences were observed.
We thank the following for making material available for study: D. Catania (CAS), S. Kullander (NRM), D. Nelson (UMMZ), L. Parenti (USNM) and K. Lim (ZRC). Thanks are also due to L. Kosygin (ZSI) for providing photographs of the type series of Mystus pulcher for study, and to Kevin Conway for providing the scanned image in Fig.
Comparative material
Mystus cineraceus: NRM 41017 (holotype), 103.0 mm SL; NRM 40977 (9 paratypes), 50.1–88.6 mm SL; NRM 41015 (5 paratypes), 54.7–90.3 mm SL; UMMZ 248754 (2 paratypes), 76.0–89.7 mm SL; Myanmar, Kachin state, lower 300 m of Nant Yen Khan Chaung, affluent of Lake Indawgyi, little S of Lonton Village, 25°6′0″N 96°16′59″E. NRM 40708 (4 paratypes), 67.5–89.2 mm SL; Myanmar, Kachin state, Myitkyina market, 25°23′N 97°24′E.
Mystus dibrugarensis: Data from
Mystus falcarius: CAS 89001, holotype, 170.2 mm SL; Myanmar: Kachin State, Myitkyina market. BMNH 1891.11.30.210–219 (13 paratypes), 96.0–139.6 mm SL; Myanmar: Sittaung River and adjacent streams from Taungoo to about 240 km S. CAS 79033 (2 paratypes), 118.8–124.8 mm SL; Myanmar: Yangon market. CAS 89000 (4 paratypes), 92.2–125.8 mm SL; USNM 344668 (6 paratypes), 74.8–99.0 mm SL; Myanmar: Sagaing Division, Pinda River in vicinity of Pinda Village, 23°10'59"N 94°5'37"E. CAS 92932 (1 paratype), 101.6 mm SL; Myanmar: Taninthayi Division, Tenasserim River backwater, midway between Htee-tah and Baowashung. CAS 96569 (1 paratype), 190.4 mm SL; Myanmar: Taninthayi Division, Tenasserim River and tributaries midway between Htee-tah and Baowashung. USNM 343550 (1 paratype), 80.1 mm SL; Myanmar: Bago Division, Sittaung River at Taungoo. NRM 53823 (1), 144.9 mm SL; Myanmar: Yangon, Insein market.
Mystus gulio: CAS 88628 (12), 74.5–111.3 mm SL; Myanmar: Bago Division, Bago market. USNM 343552 (5), 78.0–104.5 mm SL; Myanmar: Yangon Region, Thanlyin market, most probably from Bago River.
Mystus leucophasis: USNM 44752 (1), 158.2 mm SL; USNM 44798 (1), 83.6 mm SL; Myanmar: Mandalay. USNM 34469 (2), 149.7–174.6 mm SL; Myanmar: Sagaing Division, Kalemyo fish markets.
Mystus ngasep: Data from
Mystus prabini: Data from
Mystus pulcher: ZSI F4716/1, lectotype, 52.8 mm SL; ZSI F4717/1, paralectotype, 51.7 mm SL; Myanmar: Bhamo. CMK 26828 (3), 52.0–62.8 mm SL; Myanmar: Sagaing Division, oxbow lake of Irrawaddy River, about 37 km downriver of Shwegu, 24°17′11″N 96°28′30″E. CMK 27151 (1), 57.7 mm SL; Myanmar: Sagaing Division, Irrawaddy River upstream of Hti Chaint, Sa Khan Kyaut Maw Inn, 23°46′23″N 96°10′22″E. CMK 27210 (5), 29.6–69.9 mm SL; Myanmar: Sagaing Division, Irrawaddy River near Hti Kone village, about 55 km N of Mandalay, newly flooded side arm, 22°26′41″N 96°0′18″E. CMK 26894 (4), 34.9–49.3 mm SL; Myanmar: Sagaing Division, Irrawaddy River at Pha Ya Kyun village, opposite Mandalay, 21°56′24″N 96°2′4″E. CMK 28190 (4), 56.6–79.0 mm SL; Myanmar: Bago Division, Bago Division, Watt Kya Chaung at Watt Kya Village, small tributary of Bago River, 17°37′18″N 96°14′45″E. USNM 343556 (11), 55.6–61.1 mm SL; Myanmar: Yangon Region, Thanlyin market, most probably from Bago River.
Mystus rufescens: USNM 344671 (2), 73.3–85.0 mm SL; Myanmar: Kachin State, Nan Kwe stream, approximately 10 miles SW of Myitkyina along main N–S road at town of Nan Kwe. CAS 81544 (9), 90.5–123.0 mm SL; CAS 88608 (2), 67.0–85.9 mm SL; ZRC 50646 (1), 70.7 mm SL; Myanmar: Mandalay market. USNM 346162 (1), 121.5 mm SL; Myanmar: Sagaing Division, Kanbalu township, Chatthin Wildlife Sanctuary, Kye-In (lake). CAS 88616 (1), 79.0 mm SL; Myanmar: Bago division, Bago market. CMK 17783 (4), 65.2–89.0 mm SL; Myanmar: Kayin State, stream “Chon Son” between Kyondaw and Phadaw, about 20 km NW of Payathouzu (at border with Thailand), 15˚25′N 98˚15′E. NRM 39913 (1), 104.6 mm SL; Myanmar: Pagan market.