Thursday, November 30, 2023

[Ichthyology • 2023] Balitora anlongensis • the First Cavefish Species of the Genus Balitora (Cypriniformes: Balitoridae) from Guizhou Province, southwest China

Balitora anlongensis Luo, Chen, Zhao, Yu, Lan & Zhou,

in Luo, Chen, Zhao, Yu, Lan, Zhou, Xiao et Zhou, 2023.

This work describes a new species, Balitora anlongensis sp. nov., collected from a cave at Xinglong Town, Anlong County, Guzihou, China. Phylogenetic trees reconstructed based on two mitochondrial and three nuclear genes show that the new species represents an independent evolutionary lineage with large genetic differences, 7.1%–12.0% in mitochondrial gene cytochrome b and 9.2%–12.1% in cytochrome oxidase subunit 1, from congeners. Morphologically, the new species can be distinguished from the 18 species currently assigned to the genus Balitora by a combination of characters, most clearly by having two pairs of maxillary barbels; 8½ branched dorsal-fin rays; 5½ branched anal-fin rays; pectoral fin not reaching pelvic fin origin; dorsal-fin origin in front of pelvic fin origin; eye small (eye diameter approximately equal to outer maxillary barbel length); and fins lacking pigment in live fish. The new species represents the first record of Balitora inhabiting caves in China and increases the number of species in the genus Balitora in its present concept from 18 to 19. The study suggests that more evidence is needed to further clarify the taxonomic composition of the genus Balitora.

Key words: Nanpanjiang River, stone loach, taxonomy, phylogeny
Morphological characters of holotype GZNU20230215007 of Balitora anlongensis sp. nov. in preservative (10% formalin)
A lateral view B dorsal view C ventral view D ventral side view of head, and E dorsal side view of head. Photos from Tao Luo. Abbreviations: M, maxillary barbels; AN, anterior nostril.

Balitora anlongensis sp. nov. in life, paratypes GZNU20230106001 (photos A and B) and GZNU20230215014 (photo C)
A right-side view B ventral side view, and C dorsal view.
Photographs A, B were shot indoors at ~ 9:00 p.m. Photo C was taken in the cave at ~ 15:00 noon.

 Balitora anlongensis Luo, Chen, Zhao, Yu, Lan & Zhou, sp. nov.

Diagnosis: Balitora anlongensis sp. nov. can be distinguished from other congeners by the following combination of characters: (1) two pairs of maxillary barbels; (2) dorsal fin rays iii, 8½; (3) pectoral fin viii, 11; (4) pelvic fin rays ii, 9; (5) anal fin rays iii, 5½; (6) lateral-line scales 66–68; (7) tip of pectoral fin not reaching to the pelvic fin origin; (8) dorsal fin origin anterior to the pelvic fin origin; (9) tip of the pelvic fin reaching to the anus; (10) eyes small, eye diameter equal to outer maxillary barbel length; (11) six to seven indistinctly separated transversely oval blotches on the dorsal side; and (12) each fin transparent and unpigmented in life.

Etymology: The specific epithet “anlongensis” is in reference to the type locality of the new species: NaNao Village, Xinglong Town, Anlong County, Guizhou Province, China. We propose the common English name “Anlong stone loach” and the Chinese name “ān lóng Pá Qīu (安龙爬鳅)”.

 Tao Luo, Zhi-Xia Chen, Xin-Rui Zhao, Jing Yu, Chang-Ting Lan, Jia-Jun Zhou, Ning Xiao and Jiang Zhou. 2023. Balitora anlongensis, the First Cavefish Species of the Genus Balitora (Teleostei, Balitoridae) from Guizhou Province, southwest China. ZooKeys. 1185: 21-42. DOI: 10.3897/zookeys.1185.108545