Euchiloglanis longus, Zhou, Wei, Li, Xu & Thomson, Alfred W., 2011

Zhou, Wei, Li, Xu & Thomson, Alfred W., 2011, Two new species of the Glyptosternine catfish genus Euchiloglanis (Teleostei: Sisoridae) from southwest China with redescriptions of E. davidi and E. kishinouyei, Zootaxa 2871, pp. 1-18 : 13-15

Euchiloglanis longus , n. sp.

( Fig. 2 D, Fig. 3 D, Fig. 7 )

Holotype. SWFC 200311007, 154.9 mm TL, 135.2 mm SL; Mola, 24°26’54.07’’ N, 100°49’58.77’’ E, a small tributary of Chuanhe, upper Lixian-Jiang, a tributary of Red River, Jingdong Co., Yunnan Prov.; Q Wang, 1 Nov. 2003.

Paratypes. UF 177383, 2 ex. 140.0–151.0 mm TL, 126.7–135.2 mm SL and SWFC 200311001-06, 200311008-18, 200311023, 18 ex., 94.0–249.0 mm TL, 79.9–221.9 mm SL; data as for holotype. SWFC 200412001-13, 13 ex., 66.0– 217.3 mm TL, 59.1–191.5 mm SL; Guoqing, 22°37’27.98’’ N, 101°53’00.08’’ E, Jianma-He, a small tributary of the Lixian-Jiang, Red River basin, Jiangcheng Co., Yunnan Prov.; Y Yang and W Zhou, 8 Dec. 2004.

Diagnosis. Euchiloglanis longus differs from E. longibarbatus n. sp. by having a pointed maxillary barbel, not elongated as a thread, with the tip only reaching to the gill opening ( Fig. 2 D) (vs. the maxillary barbel elongated as a thread, with the tip reaching beyond the gill opening, Fig. 2 C). Euchiloglanis longus differs from E. kishinouyei and E. longibarbatus n. sp. by having one median indentation in the premaxillary tooth band ( Fig. 3 D) (vs. indentations absent in E. kishinouyei , Fig. 3 B and E. longibarbatus n. sp. with three indentations in the premaxillary tooth band, one in the middle and two on the sides, Fig. 3 C). Euchiloglanis longus differs from E. davidi by having the length of the pectoral fin equal to 78.4–89.5% (vs. 90.5–117.1%) of the distance between the insertions of the pectoral and pelvic fins and from E. kishinouyei and E. longibarbatus n. sp. by having the distance between the insertion of the pelvic fin and the anus equal to 108.9–140.6% (vs. 81.5–97.5 and 75.5–92.2%, respectively) of the distance between the insertions of the pectoral and pelvic fins. Euchiloglanis longus differs from E. davidi , E. kishinouyei and E. longibarbatus n. sp. by having the depth of the caudal peduncle equal to 14.1–27.0% of the caudal-peduncle length (vs. 29.3–46.2, 28.2–34.3, and 26.8–44.5%, respectively) ( Tables 1 and 3). Euchiloglanis longus differs from E. dorsoarcus by having the anal-fin origin closer to the caudal-fin base than to the pelvic-fin origin (vs. the anal-fin origin closer to the pelvic-fin origin than to the caudal-fin base), and from E. phongthoensis by having the distance from the adipose-fin origin to the dorsal-fin insertion about 50% of the length of the adipose-fin base (vs. equal to the length of the adipose-fin base).

Description. Morphometric and meristic data are given in Table 3. Head compressed and snout broadly rounded when viewed dorsally. Eyes small and embedded in skin, located on dorsal surface of head; distance from pupil to tip of snout longer than to dorsal corner of gill opening. Barbels flattened, in four pairs. Nasal barbel with small flap of thin skin fringing posterior margin, not reaching or reaching only to anterior margin of orbital. Maxillary barbel with small flap of thin skin, not elongated as a thread ( Fig. 2 D), reaching gill opening. Origin of inner mandibular barbel close to ventromedial line. Outer mandibular barbel almost reaching pectoral-fin origin.

Mouth inferior and transverse. Anterior margin of premaxillary tooth band exposed when mouth closed. Oral teeth conical and pointed, arranged irregularly and embedded in skin. Premaxillary tooth band crescent-shaped with a median indentation, depth of which increases slightly with growth. Lateral edges of premaxillary tooth band extend posteriorly ( Fig. 3 D). Gill opening extends from posttemporal region to base of first pectoral-fin element. Post-labial groove interrupted, ending at base of inner mandibular barbel. Lower lip connected to base of maxillary barbel by skin flap, without sulcus between them.

Dorsal profile rising gradually from tip of snout to origin of dorsal fin, then gradually sloping ventrally to end of caudal peduncle. Body gradually compressed behind origin of adipose fin. Surface of abdomen flattened. Body more slender with growth. Oral region and anterior part of abdomen with dense papillae gradually decreasing posteriorly.

Dorsal fin located at point through anterior third of body. Distance from dorsal-fin origin to tip of snout longer than distance from dorsal-fin origin to adipose-fin origin. Dorsal fin without spine, distal margin truncate. Tip of last dorsal-fin ray extending beyond vertical through pelvic-fin insertion when depressed. Adipose fin not connected with caudal-fin base, posterior margin concave, free. Origin of adipose fin anterior to or opposite vertical through tip of pelvic-fin rays. Adipose-fin base shorter than predorsal length. Distance from anal-fin origin to base of caudal fin shorter than distance from anal-fin origin to pelvic-fin origin. Pectoral fin not extending to pelvic-fin origin. Distance from pelvic-fin origin to anal-fin origin longer than distance from pelvic-fin origin to pectoral-fin origin. Pelvic fin reaching beyond anus. Anus close to pelvic-fin insertion, located at one-third distance from pelvic-fin insertion to anal-fin origin. Caudal fin truncate. Lateral line completed, mid-lateral and distinct.

Holotype Paratypes

Locality Yunnan: Jingdong Yunnan: Jingdong, Jiangcheng Number specimens 33

Dorsal-fin rays i, 5 i, 5–6

Pectoral-fin rays i, 15 i, 14–16

Pelvic-fin rays i, 5 i, 5

Anal-fin rays i, 4 i, 4

Branched caudal-fin rays 7+8 7+8

in % of standard length mean range SD Predorsal length 34.5 33.8 28.4–41.8 2.41 Dorsal-fin base length 9.8 10.4 8.0–13.2 1.33 Body depth 10.2 10.6 7.2–14.3 1.52 Head length 22.7 22.5 16.7–26.4 2.51 Maximum head width 19.4 19.1 16.6–22.2 1.50 Caudal peduncle length 24.5 22.3 18.4–26.1 1.68 Caudal peduncle depth 4.6 4.5 3.4–5.5 0.55 Dorsal-fin insertion to adipose-fin origin 16.8 19.4 15.6–23.4 2.10 Snout to adipose-fin origin 60.7 61.5 57.4–66.3 2.59 Dorsal-fin length 17.3 18.4 15.3–29.4 2.66 Pectoral-fin length 23.7 23.0 19.5–26.3 1.74 Pelvic-fin length 17.4 16.6 13.5–19.9 1.47 Anal-fin length 14.5 13.8 11.8–17.33 1.15 Anal-fin base length 6.8 7.0 5.3–13.0 1.43 Caudal-fin length 14.4 14.3 11.0–19.1 2.25 Adipose-fin base length 28.4 30.0 24.7–63.0 6.46 in % of head length

Snout length 49.5 52.2 30.8–65.3 6.40 Eye diameter 8.5 7.4 5.5–12.0 1.40 Interorbital width 25.1 28.3 23.0–38.7 3.68 in % of Pt-Pl length

Pectoral-fin length 91.7 89.0 78.5–103.3 5.22 Pl-A length 119.4 124.6 97.8–148.6 10.29 in % of Pl-A length

Pelvic-fin length 56.2 51.5 43.1–68.4 5.35 in % of length of caudal peduncle

Caudal-peduncle depth 18.7 20.6 14.1–27.0 3.36 Coloration in fresh specimens. According to collecting records, gray-black dorsal surface, milk-white venter. A pair of small yellow spots on each side of supraoccipital region. A small, oval, yellow spot at dorsal-fin origin and a pair of small yellow patches on each side of dorsal-fin origin and dorsal-fin insertion. Middle of dorsal fin with a yellow band, becoming narrower with growth. Origin and insertion of adipose fin each with narrow yellow patch. Upper and lower edges of caudal fin each with narrow yellow patch. Pectoral and pelvic fins dark gray with lighter color around distal edges. Pelvic-fin origin and the first unbranched fin ray with distinct light yellow patches. Caudal fin gray-black with small yellow patch in middle.

Distribution. Known only from the Lixian-Jiang, the upper Black River (Song Da), a tributary of Red River ( Fig. 4 ).

Habitat and ecology. The landscapes of two localities where types collected are streams in valleys. The river beds are narrow and shallow, about 10 m wide and 0.5–1 m deep with cobblestones, gravels and rock substrate. The current is rapid and the water is clear. Euchiloglanis longus lies and creeps on the substrate with it’s flatten oral region to anterior part of abdomen. Sometimes it quickly moves by swinging its slender caudal peduncle. According to villagers, Euchiloglanis longus mainly scrapes lichen growing on surface of cobblestones and gravels, feed on pieces of aquatic plants and organic scraps. Adults spawn in apertures of the river bottom in May to June and the eggs are viscous.

Etymology. From the Latin adjective longus , meaning long, referring to the long body and long caudal peduncle.

Figures

FIGURE 2. Ventral view of maxillary barbel. A, B & D, maxillary barbel pointed, not elongated as a thread [A, Euchiloglanis davidi, topotype, SWFC 200204018, 111.0 mm SL, Muping, Baoxing Co., Sichuan Prov., China; B, E. kishinouyei, topotype, SWFC 200505071, 124.4 mm SL, Guankou, Dujiangyan City (formerly Kwan-hsien or Guanxian Co.), Sichuan Prov., China; D, E. longus, SWFC 200311007, holotype, 135.2 mm SL, Mola, Jingdong Co., Yunnan Prov., China]; C, maxillary barbel slen- der, pointed, elongated as a thread (E. longibarbatus, SWFC 200505059, paratype, 175.2 mm SL, Sigongli, Yajiang Co., Sichuan Prov., China).

FIGURE 3. Ventral view of premaxillary tooth band. A & D, premaxillary band with a median indentation (A, Euchiloglanis davidi, SWFC 200204018, 111.0 mm SL, Muping, Baoxing Co., Sichuan Prov., China; D, E. longus, SWFC 200311001, paratypes, 221.9 mm SL, Mola, Jingdong Co., Yunnan Prov., China); B, premaxillary band without indentation (E. kishinouyei, SWFC 200505071, topotype, 124.4 mm SL, Guankou, Dujiangyan City [formerly Kwan-hsien or Guanxian Co.], Sichuan Prov., China); C, premaxillary band with three indentations (E. longibarbatus, SWFC 200505059, paratype, 175.2 mm SL, Sigongli, Yajiang Co., Sichuan Prov., China).

FIGURE 4. Collecting localities of examined specimens of Euchiloglanis. A symbol may represent several adjacent localities. 1, Min-Jiang, upper tributary of Yangtze River; 2, Qingyi-Jiang, branch of Dadu-He; 3, Dadu-He, branch of Min-Jiang; 4, Yalong-Jiang, upper tributary of Yangtze River; 5, Jinsha-Jiang, upper Yangtze River; 6, Jaling-Jiang, branch of Yangtze River; 7, Wu-Jang, branch of Yangtze River; 8, Yuan-Jiang, the upper Red River; 9, Lixian-Jiang, branch of Red River; 10, Mekong River; 11, Salween River.

FIGURE 7. Euchiloglanis longus, SWFC 200311007, holotype, 135.2 mm SL; Mola, Jingdong Co., Yunnan Prov., China. Dorsal, lateral and ventral views. Scale bar = 10 mm.