Barbatula zhangwuensis, Chen & Zhang & Chen & Freyhof, 2019

Chen, Hao, Zhang, Hui, Chen, Yongxia & Freyhof, Jörg, 2019, A review of the Barbatula loaches (Teleostei: Nemacheilidae) from north-eastern China, with the description of four new species, Zootaxa 4565 (1), pp. 1-36 : 27-33

Barbatula zhangwuensis , new species

( Fig. 29–31 )

Holotype. HU 1609235, 82.3 mm SL; China: Liaoning prov.: Liu River at Ertaizicun of Zhangwu, Liao River drainage, 42°40′N 122°43′E (11); Hao Chen , May 2017.

Paratypes. HU 1609229–31, 3, 73.9.1– 96.6 mm SL; FSJF 4048 , 1 , 85.8 mm SL; the same data as holotype .

Additional material examined. HU 1609244, 1609246–47, 1609253–54, 1609256, 1609264, 1609259–61, 10, 77.4–90.4 mm SL; China: Inner Mongolia: Muxiga River south of Muxiga, upper Liao River drainage, 43°73′N 117°66′E (7); Hao Chen, Aug. 2017.—HU 1609269, 1, 91.8 mm SL; China: Liaoning prov.: Pushi River at Xudianzi of Dandong Kuandian Manchu Autonomous, Yalu River drainage, 40°68′N 124°73′E (14); Hao Chen, Oct. 2016.—HU 1608316, 1, 86.4 mm SL; China: Jilin prov.: Erdaobai River 10 km east of Songjiangzhen, lower Songhua River of the middle Heilongjiang River drainage, 42°58′N 128°19′E (17).

Material used in the molecular genetic analysis. HU 1609185; China: Inner Mongolia: Muxiga River, upper Liao River drainage, 43°73′N 117°66′E (7). (GenBank accession number: MF770521 ).— HU 1609229; China: Liaoning prov.: Liu River, Liao River drainage, 42°40′N 122°43′E (11). (GenBank accession number: MF 770522 ) .— HU 1609269; China: Liaoning prov.: Pushi River, Yalu River drainage, 40°68′N 124°73′E (14). (GenBank accession number: MF 770523 ) .

Diagnosis. Barbatula zhangwuensis is distinguished from all other species of Barbatula in north-eastern China by the dorsal-fin origin situated in front of the middle between the tip of the snout and the caudal-fin base (vs. behind or at middle) and the pelvic-fin origin behind the vertical through the dorsal-fin origin (vs. below or in front).

Barbatula zhangwuensis is further distinguished from the other species of Barbatula in north-eastern China by a combination of characters, none of them unique. It is distinguished by having a pointed snout, head width at posterior margin of operculum 1.6–1.8 times in its width at anterior nostril (vs. blunt, 1.3–1.5 in B. nuda , B.ton, B. gibba i, B. kirinensis , B. pechiliensis , B. emuensis and B. linjiangensis ), widely spaced nostrils (vs. closely set in B. nuda , B. emuensis and B. linjiangensis ), the snout shorter than the postorbital head length (vs. equal in B. nuda and B. toni ), a shallow median incision in the upper lip, its depth is 10–20% of the width of the upper-lip (vs. deep, 50– 60% in B. nuda , B. gibba and B. emuensis ), a blade-shaped lateral expansion of the mental lobe (vs. without in B. nuda , B. toni , B. gibba , B. kirinensis , B. emuensis , B. linjiangensis and B. potaninorum ), the upper jaw completely covered by the upper lip (vs. partly covered in B. nuda , B. kirinensis , B. emuensis and B. linjiangensis ), a slightly convex dorsal profile (vs. convex in B. toni , B. gibba and B. pechiliensis ), 7½ branched dorsal-fin rays (vs. 6½ in B. potaninorum ), scales restricted to the back and flank behind the dorsal-fin origin (vs. scales present anterior to the dorsal-fin origin in B. toni , B. kirinensis , B. emuensis , B. liaoyangensis and B. linjiangensis ).

See Table 3 for the character states shown by the different species of Barbatula found in north-eastern China.

Description. See Figure 29–30 for general appearance and Table 2 for morphometric data. Body elongate, roundish; caudal peduncle compressed. Dorsal profile slightly convex, parallel with ventral profile; caudalpeduncle depth 61–70% of body depth at dorsal-fin origin. Ventral profile between anal-fin base and caudal-fin origin concave. Head wider than deep, head depth 81–90% in its width at posterior margin of operculum. Mouth inferior and arched ( Fig. 31a ). Snout rounded, short and pointed; head width at posterior margin of operculum 1.6– 1.8 times in its width at anterior nostril. Snout shorter than postorbital head length. Eye small, set close to dorsal profile. Anterior and posterior nostril widely spaced, gap between nostrils equal or shorter than width of posterior nostril ( Fig. 31b ). Caudal fin truncate. Caudal-peduncle length 95–100% in HL, caudal-peduncle width 43–49% its depth. Distance between anus and anal-fin origin shorter than eye diameter. Dorsal-fin origin situated in front of middle between tip of snout and caudal-fin base. Pelvic-fin origin behind vertical through dorsal-fin origin. Analfin origin anterior to midpoint between pelvic-fin origin and caudal-fin base.

Lateral line complete, reaching to caudal-fin base. Scales only sparsely scattered on back and flank behind dorsal-fin origin, densely set on caudal peduncle. Scales on caudal peduncle with small focal zone and 27–30 radial grooves ( Fig. 31c ). Anterior nostril with short tube, posterior tube shorter or without. Width of anterior nostril smaller than width of posterior nostril ( Fig. 31b ). Upper jaw unexposed, completely covered by upper lip. Upper lip with very shallow median incision, its depth 10–20% of width of upper lip. Lower lip widely separate in middle. Mental lobe with blade-shaped lateral expansion. Interspace between mental lobes narrow, exposing small part of lower jaw. Lower jaw with elongated club-shaped protrusion, formed by produced antero-ventral angles of symphyseal tip of dentary. Lower lip with short lateral expansion, its length is 50–70% of width of upper-lip ( Fig. 31a ). Maxillary barbel usually reaching to posterior eye margin, inner rostral barbel usually reaching to anterior margin of posterior nostril, outer rostral barbel usually reaching to posterior half to middle of snout. In few individuals, barbels slightly shorter.

Dorsal fin with 4 unbranched and 7½ branched rays. Anal fin with 2 unbranched and 5½ branched rays. Caudal fin with 7–8+8 branched rays. Pectoral fin with 1 unbranched and 10–11 branched rays. Pelvic fin with 1 unbranched and 6–7 branched rays. Infraorbital canal confluent with occipital canal, not confluent with supraorbital canal. Infraorbital canal with 12–14 pores, supraorbital with 8–9, occipital with 3, mandibular and preopercular with 13–14 pores. Intestine Z-shaped, anterior margin of zigzag loop not touching U-shaped stomach.

Colouration in alcohol. Background colour pale yellow with dark-brown pattern. Back with 10–14 large, dark-brown bars. Interspaces between the bars narrower than width of them. Flank with large cloud-like mottling. Caudal fin hyaline with 4–5 dark-brown bands formed by spots. Dorsal fin hyaline with 3–5 dark-brown bands formed by spots. Pectoral and pelvic fins hyaline without pigmentation.

Sexual dimorphism. Males have a longer pectoral-fin than females (pectoral-fin length 17–19% SL vs. 12– 16% in female) and the 2nd–7rd branched pectoral-fin rays are thickened in males (vs. not in female).

Distribution. Known from the Muxiga and Liu Rivers, tributaries of the Liao River, the Pushi River, a tributary of the Yalu River and the Erdaobai River. The Yalu River forms the border between China and North Korea and we expect B. zhangwuensis also to occur in North Korea. See Figure 2 for details.

Etymology. The name of the species is derived from its type locality in the Chinese Zhangwu. An adjective.

Remarks. With five species of Barbatula found in the Liao River drainage, there is a surprising diversity of loaches in such a relatively small river. However, no more than two species seem to occur in syntopy. We found B. pechiliensis and B. toni together in the Yin River in the upper reaches of the West Liao River, and B. liaoyangensis and B. nuda together in the Taizi River in the lower reaches of the Liao River. Only B. zhangwuensis was found in the Muxiga River, one of the tributaries of the upper West Liao River and in the Liu River in the middle Liao River drainage.

Four Barbatula species have been found in the Heilongjiang River drainage so far. These are B. toni , B. emuensis , B. kirinensis and B. zhangwuensis . Barbatula kirinensis and B. emuensis are found in sympatry in the Zhu’Erduo River in the upper Mudan River and B. zhangwuensis and B. emuensis co-occur in sympatry in the Erdaobai River in the lower Songhua River of the middle Heilongjiang River drainage. Only B. toni is widely distributed in the upper and lower Heilongjiang River ( Fig. 3 ).

Three species of Barbatula , B. emuensis , B. linjiangensis and B. zhangwuensis , are found in the Yalu River drainage. We found all three species at one of our four sampling sites in the Yalu River drainage, in the Pushi River. While in the Ai River and the main stem of the Yalu River (in Linjiang City) we found only B. linjiangensis and in the Hun River we found only B. emuensis .

Figures

FIGURE 2. Map showing the collection sites. Details for each number are listed in material examined.

FIGURE 3. Bayesian tree inferred from mitochondrial cytochrome b gene sequences. Clade credibility values were given for nodes with bootstrap support for ML (below branch) and posterior probability for Bayesian inferences (above branch).

FIGURE 29. Barbatula zhangwuensis, from the top: HU1609235, holotype, 82.3 mm SL; HU1609231, paratype, 96.6 mm SL; HU1609264, 90.4 mm SL; China: Liaoning prov.: Liao River drainage.

FIGURE 30. Barbatula zhangwuensis, from the top: HU1609260, 77.4 mm SL; HU1609231, paratype, 96.6 mm SL; HU1609264, 90.4 mm SL; China: Liaoning prov.: Liao River drainage.

FIGURE 31. Barbatula zhangwuensis, HU1609235, holotype, 82.3 mm SL; China: Liaoning prov.: Liao River drainage. Scale bars: a–b = 1 mm, c = 0.1 mm.