Claea Kottelat, 2011

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 : 411-413

Claea Kottelat, 2011

Oreias Sauvage, 1874: 334

(type species: Oreias dabryi Sauvage, 1874 , by monotypy; preoccupied by Oreias Kaup, 1829 in Aves and Oreias Temminck in Temminck & Laugier, 1839 in Aves). Gender feminine.

Claea Kottelat, 2011: 384 (replacement name for Oreias Sauvage 1874: 334 ). Gender feminine.

Diagnosis

Claea is distinguished from all other nemacheilid genera by having a combination of the following characters: no sexual dimorphism in breeding tubercles ( Figure 4 ), no nasal barbel; anterior and posterior nostrils set closely ( Figure 4a ); no adipose crests along dorsal and ventral midlines of caudal peduncle ( Figure 5 ); a median processus dentiformis on upper jaw ( Figure 6 ); no pelvic axillary lobe ( Figure 5 ); no black vertical bar on caudal-fin base; pelvic fins inserted slightly in front of dorsal fin ( Figure 5 ); and an unscaled body.

None of the aforementioned characters is unique to Claea . Pelvic fins inserted anterior to the dorsal-fin origin are shared with Aborichthys Chaudhuri , Draconectes Kottelat , Dzihunia Prokofiev , Lefua , and Turcinoemacheilus Bănărescu & Nalbant , and with some species of Barbatula , Indoreonectes Rita & Bănărescu , Oreonectes Günther , Schistura , Triplophysa and Troglonectes Zhang, Zhao & Tang. Among these genera, Claea shares an unscaled body with Draconectes and Trucinoemacheilulus, and with some species of Oreonectes , Triplophysa , and Troglonectes . It is distinct from Draconectes in having a furrowed (vs. smooth) lips, and lacking dorsal and ventral midline crests on the caudal peduncle (vs. present), pores of the lateral line system on the body and head situated at the tip of small papillae (vs. present), and a row of papillae along each side of the dorsal-fin base (vs. present); from Oreonectes and Troglonectes in possessing anterior and posterior nostrils set closely (vs. set separately), a complete (vs. incomplete or no) lateral line, no nasal barbel (vs. present), a moderately forked (vs. rounded or truncate in Oreonectes ) caudal fin, no adipose crest along dorsal and ventral midlines of the caudal peduncle (vs. present in Troglonectes ); from Triplophysa in having no sexual dimorphism in breeding tubercles in each side of the head and dorsal surfaces of pectoral fins in males (vs. present), and a median processus dentiformis on the upper jaw (vs. absent), and from Turcinoemacheilus in having a median processus dentiformis on the upper jaw (vs. absent), furrowed (vs. smooth) lips, a complete (vs. incomplete) lateral line, and an anus located closer to the pelvic-fin insertion than to the anal-fin origin (vs. the anal-fin origin than to the pelvic-fin insertion). The data here utilized for Aborichthys are from Singh and Kosygin (2022), Barbatula from Cao and Zhang (2008), Draconectes from Kottelat (2012b), Dzihunia from Prokofiev (2001), Indoreonectes from Kumkar et al. (2021), Lefua from Hosoya et al. (2018), Oreonectes from Huang et al. (2020), Turcinoemacheilus from Esmaeili et al. (2014), and Troglonectes from Li et al. (2023)

Remarks

Claea is here viewed as a valid genus distinct from Triplophysa despite their closer relationship unveiled in our molecular phylogenetic analysis ( Figure 1 ). The current generic definition of Triplophysa includes around 160 valid species widely distributed in Central Asia, from Afghanistan and Baluchistan through the high Asian region to the Balkhash and Uvs-Nuur lakes, Outer Mongolia and China. It is apparent that a generic reclassification of Triplophysa is urgently needed to align with phylogeny. This is absolutely a great challenge so far confronting ichthyologists around the world, and can not be finished in the near future. Thus, it is provisional to treat Claea as a genus distinct from Triplophysa . Both, as conventionally delineated, mainly differ in the presence or absence of a processus dentiformis on the upper jaw and sexual dimorphism in breeding tubercles on the lateral head and dorsal surfaces of pectoral fins (see the generic diagnosis above).

The current generic diagnosis of Triplophysa by Bănărescu and Nalbant (1995) and Prokofiev (2004) is largely grounded on characters related to sexual dimorphism, thus rendering very difficult to determine the generic placement of females, immature and non-breeding males ( Deng et al. 2022). It is not surprising to find in this analysis that C. wulongensis was originally misidentified in Triplophysa . Although its specific status was established using an integrative taxonomic approach ( Chen et al. 2021), the molecular analysis had limitations in terms of sampling, focusing only on a few species of Triplophysa and lacking representation from other nemacheilid genera such as Claea . Furthermore, the analysis’ reliance on molecular data led to the oversight of critical diagnostic features related to jaw shape and sexual dimorphism. The original description of C. wulongensis failed to mention a processus dentiformis on the upper jaw and mistakenly attributed sexual dimorphism in head and pectoral fins to the breeding season ( Chen et al. 2021). Closer examination indicated that C. wulongensis possesses a median dentiform process on the upper jaw ( Figure 6b ), and lacks sexual dimorphism in breeding tubercles and pelvic axillary lobes ( Figure 7 ), characteristics that align it more with Claea than Homatula or Schistura . This generic reassignment to Claea was further corroborated by our cyt b gene-based phylogenetic analysis (see Figure 1 ).

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 4. Lateral view of head (a) and dorsal view of pectoral fin (b) of Claea minibarba sp. nov.: IHB 202204288316, holotype, 63.7 mm SL.

FIGURE 5. Lateral view of body in Claea dabryi: IHB 3514, 77.7 mm SL, South China: Sichuan Province: Ebian County: Dadu-He.

FIGURE 6. Ventral view of head for: (a)Claea minibarba sp. nov., IHB 202204288316, holotype, 63.7 mm SL and (b) C. wulongensis, SWU 2019051309, holotype, 64.0 mm SL.

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