Claea wulongensis ( Chen, Sheraliev, Shu & Peng, 2021 )

Zhang, Chu-Yi, Luo, Pan, Huang, Feng & Zhang, E., 2024, Revision of the loach genus Claea Kottelat, 2010 (Teleostei: Nemacheilidae) in China, with a description of a new species from the Chang-Jiang basin, Zootaxa 5543 (3), pp. 404-422 : 417-418

Claea wulongensis ( Chen, Sheraliev, Shu & Peng, 2021)

( Figure 7 )

Triplophysa wulongensis Chen, Sheraliev, Shu & Peng, 2021:183 (type locality: China: Chongqing: Wulong County: a subterranean pool in Furong Cave ).

Specimens examined. SWU2019051309 , holotype, 64.0 mm SL; China: Chongqing City: Wulong County: subterranean pool in Furong Cave . SWU2019051301–2019051308 , eight paratypes specimens, 49.0– 67.2 mm SL; other data same as holotype .

Diagnosis. Claea wulongensis is distinguished from two generic species by the presence of a wider interorbital space (width 38.5–43.1% of HL vs. 20.0– 33.8 in C. dabryi , and 30.3–36.3 in C. minibarba ; Figure 3a ). It, along with C. minibarba , is distinct from C. dabryi in having shorter outer rostral barbels extending away from (vs. beyond) the anterior margin of eye and shorter maxillary barbels extending to the anterior margin of eye (vs. beyond the posterior edge of eye). This species is further distinct from C. minibarba in having a lower count of vertebrae (4+38–39 vs. 4+41–43), a shallower body (depth 9.3–13.6% of SLvs. 14.7–17.6; Figure 3b ), and a shallower caudal peduncle (depth 7.6–9.4% of SL vs. 9.5–11.7; Figure 3e ).

Distribution. Known only from a pool in Furong Cave, connected to the Wu-Jiang near Wulong.

Discussion. Despite the generic recognition of Claea in the Nemacheilidae ( Kottelat 2012a; Tan & Armbruster 2018), its phylogenetic position within this family remains undetermined. Oreias (so far replaced by Claea ) was rendered synonymous to Schistura ( Zhu 1989) ; however, this synonymization was refuted as its type species possesses has no pelvic axillary lobe, a character diagnostic for Schistura ( Prokofiev 2009) . In the revision of loaches of the world by Bănărescu and Nalbant (1995), Oreias was considered to bear a closer relationship with Homatula , Longischistura McClelland, Nun Bănărescu & Nalbant , Paracobitis Bleeker , Physoschistura Bănărescu & Nalbant , Schistura , and Sectoria Kottelat for having a similar body color pattern, a processus dentiformis on the upper jaw, and no sexual dimorphism in breeding tubercles. Moreover, Liu et al.’s (2012) molecular phylogenetic analysis of the Nemacheilidae revealed that the type species of Claea (under the name of Schistura ) was clustered with analysed species of Triplophysa . The same finding was also repeated in Chen et al.’s (2019) molecular phylogenetic analysis. However, their species identification of Claea was not free from question. Therefore, their molecular evidence for the closer relationship of this genus with Triplophysa was not conclusive (see elobration below).

Our molecular phylogenetic analysis unveiled that Claea was more closely allied to Triplophysa than Homatula or Schistura in the cyt b gene-based BI tree ( Figure 1 ). In Liu et al.’s (2012) phylogenetic analysis based on concatenated mitochondrial and nuclear sequences, Triplophysa gundriseri was demonstrated to be closely related to Schistura dabryi from the Tuo-Jiang of the upper Chang-Jiang basin. The recognition of their samples under the name of S. dabryi was unlikely under molecular scrutiny of our analysis due to no use of the cyt b gene as markers of their phylogenetic inference. The species, identified by Liu et al. (2012) as S. dabryi , may be a misidentified member of Triplophysa , given its closer relationship with T. gundriseri . Currently, T. gundriseri is confined to the Tesiin River and Lake Sangiin-Nurr of Mongolia and the Uvs-Nuur Lake basin of Tuva Republic of Russia (Kottelat 2006). It is here posited to be more closely allied to species of Sbuclade 2 than Subclade 1. Despite the only use of the cyt b gene, more species of Triplophysa were sampled in our molecular analysis than in two studies aforementioned. Further research will confirm that the result of our analysis is reliable.

It is worth mentioning that sampled species of Triplophysa , detected to nest with species of Claea in our molecular phylogenetic analysis ( Figure 1 ), are troglobitic and found in Southwest China (primarily Yunnan, Guangxi and Guizhou Provinces), with the largest continuous distribution of karst landforms in China, or even in the world. Habitats of these species are quite distinct from those of epigean congeneric species. Whether or not these subterranean species represent a distinct genus from Triplophysa require further in-depth research.

The type locality of C. dabryi is Dengchigou, Baoxing County, Sichuan Province, in the Qingyi-Jiang flowing into the Min-Jiang of the upper Chang-Jiang basin ( Kottelat 2012a). The holotype (MNHN 6276, photograph examined) is broken or in bad condition, and thus of very limited taxonomic use for its identification. In light of Sauvage’s (1874) original description, C. dabryi has small eyes located in the middle of head, a flat interorbital space, with its width nearly twice the diameter of eye; pelvic fins inserted slightly in front of the dorsal-fin orgin; anal-fin origin almost equidistant from the ventral fin and caudal-fin base; and upper portion of body yellowish, mottled with dark green blotches. These characters are shared with a specimen reported and figured by Guo et al. (2021) as C. dabryi from the Dachuan-He (a part of the Qingyi-Jiang) in Lushan County, about 20 km from Baoxing County (the type locality of the species) of Sichuan Province, and can thus be considered as topotypical; two pictures (Figure 150–1 and 150–2 on Page 505) of the specimen exhibit that C. dabryi has pelvic fins inserted slightly in front of the dorsal fin, no pelvic axillary lobe, no nasal barbels, and no sexual dimorphism in breeding tubercles, and (anterior and posterior) nostrils set closely. A median processus dentiformis on the upper jaw is illustrated in the other picture (Figure 150–7 on Page 507) for this species. Guo et al.’s (2021) description, predicated on 20 specimens (including those collected from Baoxing County, the type locality of the species) of the upper Chang-Jiang basin, recorded this species with a depressed head (depth 44.4–55.6% of HL), a shallow body (depth 13.2–16.7% of SL), long maxillary barbels (length 30.4–35.0% of HL), long outer rostral barbels (length 32.6–35.0% of HL), and 4+38-42 vertebrae. Despite no accessibility to topotypical specimens, primary diagnostic characters provided in this study for C. dabryi largely agree with its original description, and also the data given by Guo et al. (2021) for this species.

Schistura niulanjiangensis , a species originally described from the Niulan-Jiang discharging into the Jinsha-Jiang of the upper Chang-Jiang basin ( Chen et al. 2006), is excluded from Claea in this study. It was transferred to this genus, but without detailed explanation ( Kottelat 2012a). Our photographic examination on the holotype ( Figure 12 , upper) indicated that this species, as stated in its original description, possesses no processus dentiformis on the upper jaw, pelvic axillary lobes present, and pelvic fins inserted slightly behind the dorsal-fin origin, three characters not placing it in Claea . Schistura niulanjiangensis is indeed a species of Triplophysa in terms of unpublished molecular data (Feng Lin, personal communication). One paratype ( Figure 12 , lower) of S. niulanjiangensis has pelvic fins inserted slightly in front of the dorsal-fin orgin as found in Claea , but not conforming to its original description. It can not be assigned to this genus due to no processus dentiformis on the upper jaw, and the presence of pelvic anxillary lobes. The generic classification and specific status of this paratype need to be determined in the future when more specimens are available.

Claea has its representative in the Niulan-Jiang. Three specimens, collected by Chun-Yun Lei (Yunnan Fisheries Science Research Institute ) from the type locality of S. niulanjiangensis , were initially recognized as this species. Our careful examination affirmed that these three specimens indeed represent an unidentified species of Claea . The formal description of this unidentified species, however, is hindered by the paucity of available specimens.

Figures

FIGURE 1. Bayesian Inference tree generated from the cyt b gene for sampled species of the Nemacheilidae. Nodal numbers are posterior probability values greater than 50%.

FIGURE 3. Relationship between interorbital width and head length (a); body depth and standard length(b); outer rostral-barbel length and head length (c); maxillary-barbel length and head length (d); caudal-peduncle depth and standard length (e) for Claea dabryi (blue square), C. minibarba sp. nov. (red circle), and C. wulongensis (green triangle).

FIGURE 7. Lateral view of body in Claea wulongensis: SWU 2019051309, holotype, 64.0 mm SL, Southwest China: Chongqing: Wulong County: Wu-Jiang.

FIGURE 12. Lateral view of body in “Claea” niulanjiangensis (upper), holotype, Qujing Aquaculture Station 9206085, 84.0 mm SL, and Claea sp. (lower) from the Niulan-Jiang of the upper Chang-Jiang mainstream (Photographed by Wei-Ning Mao and Zong-Min Lu).