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| (Oreonectes I) = Karstsinnectes Zhou, Luo, Wang, Zhou & Xiao gen. nov., in Luo, Yang, Wu, Wang, J.-J. Zhou, Deng, Xiao et J. Zhou, 2023. |
Cave loaches within the family Nemacheilidae are among the most diverse group of cavefish in southwestern China. Although certain species have been included in previous phylogenetic studies, the intergeneric and interspecific relationships of Chinese cave loaches in Nemacheilidae remain poorly investigated due to insufficient sampling. In this study, a total of 45 samples from 37 recognized species and two unidentified species of cave loaches were collected, accounting for 87.5% of the eight recognized genera of cave loaches within the family Nemacheilidae in China. The complete mitochondrial genome (mitogenome) and seven nuclear genes were sequenced, and the phylogenetic tree of Chinese cave loaches was reconstructed. Both Bayesian inference and maximum-likelihood analyses resolved the phylogenetic relationships at the generic and species levels, suggesting the effectiveness of this multilocus marker system in determining phylogenetic relationships in Chinese cave loaches. Phylogenetic analysis not only confirmed previous taxonomic hypotheses based on morphological data but also provided new insights into the relationships of many cave loaches at the genus and species levels as well as suggestions for the current taxonomy of cave loaches within the family Nemacheilidae.
The karst regions of southwestern China are considered the center of Chinese cavefish biodiversity, boasting the most concentrated distribution of cavefish in the world. However, many cavefish species in the region remain poorly known and highly threatened (IUCN, 2022). Nemacheilidae, which contains approximately 22 genera and 269 species, constitutes one of the largest and most diverse families, second only to Cyprinidae in terms of diversity (Zhang et al., 2020). These cave loaches, which include both stygophilic and stygobitic species, are restricted in their distribution to the karst regions of southwestern China and exhibit highly specialized morphologies (Lan et al., 2013; Li, 2018). This has led to inadequately resolved taxonomies and enigmatic phylogenetic relationships among cave groups. The presence of both subterranean and surface-dwelling phenotypes among these genera, as well as the influence of convergent evolution, make it challenging to distinguish them based on morphological characteristics alone. The classification of Chinese cave loaches has been the subject of debate, ...
Karstsinnectes Zhou, Luo, Wang, Zhou & Xiao, gen. nov.
Type species: Oreonectes anophthalmus Zheng, 1981.
Diagnosis: (1) body naked, scaleless, and body color pattern absent; (2) eyes absent; (3) lips with furrows but no papillae; (4) anterior and posterior nostrils slightly separated, anterior nostril tube long, without elongated short barbel-like tip; (5) without longitudinal stripe; (6) dorsal fin with 7 branched rays, dorsal-fin origin slight posterior to ventral-fin origin; (7) caudal fin forked or rounded, caudal peduncle with adipose crests; (8) cheeks scaleless; (9) lateral line and cephalic lateral-line canals present; (10) bony capsule of swim bladder open posteriorly.
Etymology: The genus name Karstsinnectes is a combination of words. Karst is an English word meaning an area of water-eroded limestone; sin is an abbreviation of the Greek word Sino, refers to Chinese; nectes, a Greek word meaning swimmer. We suggest its English common name “Chinese Karst Loach Genus” and Chinese common name “Zhōng Huá Kā Qiū Shǔ (中华喀鳅属)”.
Distribution: Currently, this genus includes four species, i.e., Karstsinnectes acridorsalis (Lan, 2013) comb. nov., Karstsinnectes anophthalmus (Zheng, 1981) comb. nov., Karstsinnectes hyalinus (Lan, Yang & Chen,1996) comb. nov., and Karstsinnectes parvus (Zhu & Zhu, 2014) comb. nov., all of which distributed in the Hongshuihe, Zuojiang, and Youjiang river basins in Guangxi, China.
Tao Luo, Qin Yang, Li Wu, Ya-Li Wang, Jia-Jun Zhou, Huai-Qing Deng, Ning Xiao, Jiang Zhou. 2023. Phylogenetic Relationships of Nemacheilidae Cavefish (Heminoemacheilus, Oreonectes, Yunnanilus, Paranemachilus, and Troglonectes) revealed by Analysis of Mitochondrial Genome and Seven Nuclear Genes. Zoological Research. 44(4): 693-697. DOI: 10.24272/j.issn.2095-8137.2022.266
