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| Bagarius protos & B. dolichonema Zeng & Chen, in Zeng, Pu, Lei, Oo et Chen, 2025. |
Abstract
The genus Bagarius is a group of large, benthic, predatory catfishes found in South and Southeast Asia. Two new species of Bagarius, B. protos Zeng & Chen, sp. nov., and B. dolichonema Zeng & Chen, sp. nov., are described from the Salween River Basin, Yunnan Province, China, and Irrawaddy River Basin, Myanmar, respectively. Bagarius protos and B. dolichonema both differ from B. vegrandis and B. suchus in their large size and the adipose-fin origin being nearly vertical to the anal-fin origin. Bagarius protos most closely resembles B. lica and B. rutilus in overall morphology but can be distinguished from B. lica by the absence of the brow ridge formed by the lateral margin of the frontal and from B. rutilus by the dark yellow (instead of orange) coloration of the fins in life. It further differs from two other congeners in its short filamentous extensions of the pectoral-fin spine. Bagarius dolichonema is morphologically and genetically most similar to B. bagarius; it can be distinguished from B. bagarius by strong dorsal spines slightly flattened immediately anterior to the adipose fin, distally slender neural spines of the 4th–6th vertebrae, and shorter filamentous extensions of the pectoral-fin spine. This new species further differs from three other congeners by its longer filamentous extensions of the pectoral-fin spine and weak notches in the anterodorsal margin of the first dorsal pterygiophores. Molecular phylogeny based on the cytochrome c oxidase subunit I (COI) gene also confirms the validity of these two new species. The estimated K2P genetic distances between B. protos and congenerics range from 8.0% to 12.6%, and between B. dolichonema and congenerics range from 5.7% to 12.1%.
Key Words: Cryptic species, phylogeny, Southeast Asia, taxonomy
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| Living specimens of Bagarius protos sp. nov., paratype. KIZ202410548, 324 mm SL. |
Bagarius protos Zeng & Chen, sp. nov.
Diagnosis. Bagarius protos can be distinguished from congeners by having the following combination of characteristics: eye small (5–8% HL), lateral margin of frontal straight, not forming brow ridge, strongly notched in antero-dorsal margin of the first dorsal-fin pterygiophore, dorsal spine strong (width 10.6–14.4 times its length), filamentous extensions of pectoral-fin spine reaching posterior of anal-fin base, neural spines of 4th–6th vertebrae immediately anterior to adipose fin distally slender, adipose-fin origin at vertical through or very slightly posterior to anal-fin origin, caudal peduncle deep (4.2–5.1% SL).
Etymology. The epithet name “protos” consists of the Greek “protos,” meaning original (at first), referring to the species being in the most primitive position in the phylogenetic tree of genus Bagarius. The suggested common name in Chinese is 原魾 (Pinyin: yuan pi).
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| Fresh specimens of Bagarius dolichonema sp. nov., paratype, KIZ2024010542, 193.9 mm SL, photo by Tao Qin. |
Diagnosis. Bagarius dolichonema can be distinguished from congeners by the following combination of characteristics: lateral margin of frontal straight, not forming brow ridge, dorsal spine strong (width 9.9–14.1 times its length), weakly notched antero-dorsal margin on pterygiophore of first dorsal-fin, filamentous extensions of pectoral-fin spine beyond posterior of pelvic-fin base and some reaching anus, neural spines of 4th–6th vertebrae immediately anterior to adipose fin distally slightly flattened, adipose-fin origin at vertical through or very slightly posterior to anal-fin origin, caudal peduncle slender (3.8–4.6% SL).
Etymology. The epithet name “dolichonema” comes from the Greek adjective “dolikhos,” meaning long, and the noun “nēma,” meaning thread or yarn, which refers to the length of filamentous extensions with pectoral-fin spines and caudal fins that are the longest in congeners except for B. bagarius. The suggested common name in Chinese is 长丝魾 (Pinyin: chang si pi).
Yu-Yang Zeng, Xin-Rui Pu, Hao-Tian Lei, Thaung Naing Oo and Xiao-Yong Chen. 2025. A Taxonomic Review of Bagarius Catfish (Siluriformes, Sisoridae) in the Salween and Irrawaddy Rivers, with Descriptions of Two New Species from China and Myanmar. Zoosystematics and Evolution. 101(3): 1123-1136. DOI: doi.org/10.3897/zse.101.145776
