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| [A] Bashimyzon damingshanensis (Xiu & Yang, 2017) [B] Bashimyzon cheni Gong & Zhang, 2024 |
Abstract
Bashimyzon, new genus, is here established for Erromyzon damingshanensis, and a new species of the genus is described from the You-Jiang of the Pearl River (=Zhu-Jiang in mandarin Chinese) basin in Guangxi Province, South China. This new genus has a small gill opening above the pectoral-fin base and short pectoral fins extending backwards short of pelvic-fin insertions, both characters combined to separate it from all currently-recognized gastromyzontid genera except Erromyzon and Protomyzon, but differs from the two genera in having a larger gap between the posterior edge of eye and the vertical through the pectoral-fin insertion and very small fleshy lobes posterior to the maxillary-barbel bases. It is further distinct from its most similar genus Erromyzon in having a relatively larger gill opening, fewer branched pectoral-fin rays folded against body, and more posteriorly placed pectoral fins with a shorter fin base. Bashimyzon cheni, new species, and B. damingshanensis, the single congeneric species, differ in number of lateral-line pored scales, body coloration, and cephalic contour, and also in substantial genetic divergence.
Key Words: Bashimyzon, new genus, new species, taxonomy, Zhu-Jiang basin
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| Lateral view of freshly captured individual of A. Bashimyzon damingshanensis, IHB 202109064259, topotype, 30.8 mm SL; China: Guangxi Province: Shanglin County: Qingshui-He at Naxue Village of Dafeng Town; and B. B. cheni, IHB 202109064273, holotype, 28.3 mm SL; China: Guangxi Province: Mashan County: Wuming-He at Xinyang Village of Gulin Town. |
Bashimyzon gen. nov.
Type species: Erromyzon damingshanensis Xiu & Yang, 2017: 893
(type locality: Qingshui-He, tributary to Hongshui-He of Zhu-Jiang basin, in Shanglin County, Guangxi Province)
(type locality: Qingshui-He, tributary to Hongshui-He of Zhu-Jiang basin, in Shanglin County, Guangxi Province)
Diagnosis: Bashimyzon is distinct from all currently identified gastromyzontid genera except Erromyzon and Protomyzon in the presence of a gill opening restricted above pectoral-fin base (vs. gill opening elongate, extending downwards to or beyond the pectoral-fin insertion to the ventral surface of head), and pectoral fins backwards extending away from (vs. close to or beyond) pelvic-fin insertions. This new genus is separated from ....
Etymology: The generic name is derived from Bashi (岜是), the local name of the Damingshan Mountain in Zhuang nationality language, and myzon, a common suffix used in the Balitoridae. Gender masculine. The Chinese common generic name is here suggested as “岜是鳅属”.
Bashimyzon cheni sp. nov.
Diagnosis: Bashimyzon cheni is clearly distinguished from the single congeneric species B. damingshanensis in having 8–9 teardrop-shaped black blotches wider than interspaces, with the majority portion of each blotch located above the lateral line on the flank (vs. 12 irregular black bars narrower than interspaces, and located along the lateral line on the flank; see Figs 5, 6); fewer rows of blackish spots across dorsal-fin rays (3 vs. 4); fewer lateral-line pored scales (84–86 vs. 88–95); a gradual (vs. abrupt) upward dorsal profile of head in front of nostrils (Fig. 8A); a deeply (vs. slightly) curved rostral groove, or the greater (vs. less) distance from the median point of the distal margin of the upper lip to the anterior-most tip of the snout than half of the mouth width (Fig. 8B), a distinct (vs. indistinct) incision on both side of the fleshy pad of the lower lip (Figs 2B, 7).
Etymology: The specific epithet is named after Prof. Chen Yi-Yu, a Chinese Academician, in honor for his great contribution to Chinese freshwater fish research. In particular, he discovered and named the type species of Erromyzon and Yaoshania, which are two close relatives of the genus under description. The Chinese common specific name “陈氏岜是鳅” is here suggested.
Xiong Gong and E. Zhang. 2024. Bashimyzon cheni, A New Genus and Species of Sucker Loach (Teleostei, Gastromyzontidae) from South China. Zoosystematics and Evolution. 100(1): 309-324. DOI: 10.3897/zse.100.116535
