A new species of a small cyprinid fish, Metzia parva sp. nov., is described here based on specimens collected from a tributary of Hongshui-He River in the Pearl River basin at Anyang Town, Du’an County, Guangxi Province, south China. It differs from congeners in having a smaller body with a standard length of 48.3–57.7 mm (vs. 58.3–151.4 mm in other species); a complete lateral line (although some specimens show interruptions on the ventral margin above the anal-fin); 12–14 branched anal-fin rays (vs. 10–11 or 15–20); 10 branched pectoral-fin rays (vs. 11–16); 6 branched pelvic-fin rays (vs. 7–9); a longer caudal peduncle (17.8–21.7% vs. 14.8–17.4% SL); a shorter preanal length (60.9–66.0% vs. 69.0–73.0% SL) and an obviously larger interorbital width (28.4–33.0% vs. 20.2–24.7% of head length). While Metzia parva shares a lateral black stripe from the gill opening to the caudal-fin base with M. formosae, the new species can be distinguished from M. formosae by a deeper head (16.4–19.2% vs. 13.3–15.7% SL) and a longer anal fin (15.4–18.9% vs. 10.0–13.6% SL) in addition to the diagnostic characters above. Kimura's 2-parameter genetic distance between the two species is 6.6% for the barcoding region of the mitochondrial COI gene and 7.3% across the complete mitochondrial genome.
Keywords: Cypriniformes, Cyprinidae, Metzia parva, new species, Guangxi Province, China, Pisces
Distribution. Known from the Cheng-jiang River, a tributary flowing into Hongshui-He River of the Pearl River basin at Anyang Town, Du’an County, Guangxi Province, south China (23°92′N, 108°10′E, 161 meters altitude above sea-level, Fig. 5).
Reproduction. Females contained a large number of eggs. Reproductive system of males not examined closely, and no data are available on reproductive behavior.
Etymology. Metzia parva was named for its small body size with the Latin word parva (gender feminine) meaning small or little.
Luo, W., Sullivan, J.P., Zhao, H.-T. & Peng, Z.-G. 2015. Metzia parva, A New Cyprinid Species (Teleostei: Cypriniformes) from South China. Zootaxa. 3962 (1): 226–234. DOI: 10.11646/zootaxa.3962.1.14