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| Karstsinnectes daxinensis Luo, Zhou & Zhou, in T. Luo, F.-W. Luo, Lan, M.-Y. Xiao, J.-J. Zhou, Liao, N. Xiao et J. Zhou, 2024. |
Abstract
The genus Karstsinnectes of blind fishes known as karst loaches from China was established in 2023 during a revision of the genus Oreonectes (Nemacheilidae). Six species are recorded in this study and some taxonomic progress has been made; however, the lack of genetic data for some species (e.g., K. anophthalmus) may have weakened our current understanding of Karstsinnectes. This study reassessed the phylogeny and evolutionary history of Karstsinnectes by integrating a combination of previously published and newly sequenced mitochondrial genomic data. A phylogenetic tree was developed that was able to divide Karstsinnectes into two clades corresponding to drainages and clarify the phylogenetic position of K. anophthalmus. Divergence times show that Karstsinnectes originated at the Oligocene/Miocene boundary (~22.37 Mya), with the most recent common ancestor occurring in the early Miocene (~18.87 Mya) and interspecific divergence occurring in the late Miocene. Ancestral area reconstruction suggests that the most recent common ancestor of Karstsinnectes most likely inhabited the Hongshui River basin and dispersed into the Zuojiang-Yujiang, Beipanjiang, and Youjiang river basins during the early Miocene (~18.87 Mya), middle Miocene (~12.78 Mya), and late Miocene (~6.71 Mya), respectively. The dispersal under the influence of orogenesis and a monsoon climate drove the speciation and diverse distribution of Karstsinnectes. Such findings are important for conservation considering that Karstsinnectes strictly inhabits deep caves. Additionally, the taxonomic status of the distributed Karstsinnectes population in Leiping Town, Daxin County, Guangxi, China was revised by combining genetic and morphological differences to describe this population as a new species, Karstsinnectes daxinensis Luo, Zhou & Zhou, sp. nov. The definition of the phylogenetic position of K. anophthalmus emphasizes the importance of using type locality material for the identification of cryptic species.
Key Words: Biogeography, blind fishes, Karstsinnectes anophthalmus, phylogeny, taxonomy
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| Lateral, dorsal, ventral views of Karstsinnectes daxinensis sp. nov. In living. |
Karstsinnectes daxinensis Luo, Zhou & Zhou, sp. nov.
Chresonymy: Oreonectes anophthalmus: Wang, 2022 (Leiping Town, Daxin County, Guangxi, China). Karstsinnectes anophthalmus: Luo et al. 2023, 2024; Yu et al. 2023; Ge et al. 2024; Zhao et al. 2024 (Leiping Town, Daxin County, Guangxi, China).
Diagnosis: Karstsinnectes daxinensis sp. nov. can be distinguished from all of the other congeners by the following combination of characters: (1) body naked and without pigmentation; (2) eyes absent; (3) dorsal-fin rays iii-7, pectoral-fin rays i-10–11, pelvic-fin rays i-5, anal-fin rays iii-5, caudal fin truncated with 13–14 branched caudal-fin rays; (4) pelvic fins slightly long, length 9.5–13.2% of SL, tip reaching the anus; (5) high and wide head (depth 6.3–9.8% of SL; wide 10.0–14.8% of SL), narrow mouth (width 6.2–7.9% of SL), long inrostral barbel length (length 7.2–12.7% of SL), and long maxillary barbel length (length 11.3–13.1% of SL).
Etymology: The specific epithet “daxinensis” refers to the type locality of the new species: Leiping Town, Daxin County, Chongzuo City, Guangxi, China. We propose the English common name “Daxin Chinese Karst Loach” and Chinese common name “Dà Xīn Zhōng Huá Kā Qiū (大新中华喀鳅).”
Tao Luo, Fang-Wei Luo, Chang-Ting Lan, Ming-Yuan Xiao, Jia-Jun Zhou, Mei Liao, Ning Xiao and Jiang Zhou. 2024. Evolutionary History of Chinese Karst Loaches (Nemacheilidae, Karstsinnectes): new insights from Mitochondrial-based Genomes and Description of A New Species from Guangxi, China. Zoosystematics and Evolution. 100(4): 1473-1486. DOI: doi.org/10.3897/zse.100.133964