Taxonomic revision of the Southeast Asian brook barb genus Poropuntius Smith, 1931 (Teleostei, Cyprinidae) with description of a new species from Vietnam Author Hoang, Huy Duc 0000-0001-6528-193X Department of Ecology and Evolutionary Biology, University of Science, Ho Chi Minh City, Vietnam & Vietnam National University, Ho Chi Minh City, Vietnam Author Pham, Hung Manh 0000-0003-3186-818X Department of Ecology and Evolutionary Biology, University of Science, Ho Chi Minh City, Vietnam & Vietnam National University, Ho Chi Minh City, Vietnam Author Tran, Ngan Trong 0000-0001-7254-2835 Department of Ecology and Evolutionary Biology, University of Science, Ho Chi Minh City, Vietnam & Vietnam National University, Ho Chi Minh City, Vietnam Author Durand, Jean-Dominique 0000-0002-0261-0377 IRD, MARBEC (University of Montpellier, CNRS, Ifremer, IRD), Montpellier, France Author Wu, Ling https://orcid.org/0009-0001-5700-1616 Southeast Asia Wildlife Biodiversity Research Group, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650223, China & Southeast Asia Biodiversity Research Institute, Chinese Academy of Science, Yezin, Nay Pyi Taw 05282, Myanmar Author Pfeiffer, John 0000-0001-5368-0589 Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, 10 th and Constitution Avenue NW, Washington, DC 20560, USA Author Chen, Xiao-Yong 0000-0002-0924-5560 Southeast Asia Wildlife Biodiversity Research Group, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650223, China & Southeast Asia Biodiversity Research Institute, Chinese Academy of Science, Yezin, Nay Pyi Taw 05282, Myanmar Author Page, Lawrence M. 0000-0002-8823-0729 Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, FL 32611, USA text ZooKeys 2024 2024-06-06 1204 199 222 journal article 298187 10.3897/zookeys.1204.120873 57bd1d90-6de1-40c8-98a7-acac50ba37d2 34FB4522-549E-48D1-9E88-B9165112E9CC Poropuntius alloiopleurus (Vaillant, 1893) Barbus alloiopleurus Vaillant, 1893: 201 . Type locality: Vietnam , Tonkin , Black River . Holotype : MNHN 1892-0261 . Barbodes ( Barbodes ) huangchuchieni rhomboides Wu & Lin, in Wu et al. 1977: 248 , pl. 7–8. Type locality: China , Yunnan , Yuanjiang River . Syntypes (15): KIZ 645614 -15, 645617-19 , 645622 , 645624 , 6440093 , 6440392 , 6440461 , 6440564 , 6450172 , 6450191 , 6450207 , 6450322 . Poropuntius baolacensis (Nguyen, in Nguy ễn and Ngô 2001): 387 , fig. 189. Type locality: Vietnam , Cao Bang Province , Nho Que , Bao Lac [ 22 ° 56 ' 60 " N , 105 ° 40 ' 00 " E ], Song Hong River drainage. Holotype : VNCNTTS H. 01.72.13.01 . Poropuntius brevispinus ( Nguy ễn & Đoàn , 1969) : 12 , fig. 7. Type locality: Vietnam , Hoa Binh Province , Suoi Rut stream . Syntypes (3): NCNTTSI H. 01.72.10.01 - 03 . Acrossocheilus macrophthalmus Nguyen, in Nguy ễn and Ngô 2001: 390 , fig. 191. Type locality: Vietnam , Hoa Binh Province , Da Bac District , Da River at Thac Bo . Holotype : NCNTTSI H. 01.72.14.01 . Acrossocheilus xamensis Kottelat, 2000: 38 , fig. 1. Type locality: Laos , Houaphan Province , Houay Tangoua , small stream entering Nam Xam in Ban Houay Tangoua , 20 ° 09 ' 24 " N , 104 ° 32 ' 50 " E . Holotype : ZRC 45297 . Notes. Specimens of Poropuntius alloiopleurus (Fig. 3 C ) were recovered in a clade including topotypic material of Acrossocheilus macrophthalmus , A. xamensis , Barbodes huangchuchieni rhomboides , Poropuntius baolacensis , and P. brevispinus and was sister to a clade including P. heterolepidotus , P. huangchuchieni , and P. laoensis (Fig. 2 A ). Kottelat (2000) noted that Acrossocheilus xamensis resembles Poropuntius but lacks the branched lateral-line canals diagnostic of Poropuntius . Our 12 specimens of P. alloiopleurus are missing branched lateral-line canals; branched canals are variable within Poropuntius and do not distinguish Poropuntius from Acrossocheilus . A paratype of A. xamensis exhibits the typical caudal-fin characteristic of Poropuntius , a dark marginal stripe along the lower lobe ( Kottelat 2000 , fig. 1). According to Nguy ễn (2001) , A. macrophthalmus resembles P. alloiopleurus but has an eye diameter longer than the snout. Our 12 specimens of P. alloiopleurus have eye diameters that are shorter or longer than the snout. Nguy ễn and Ngô (2001) distinguished P. baolacensis from P. brevispinus in having 28–30 vs 18–22 serrae along the posterior margin of the last simple dorsal-fin ray. Our 12 specimens of P. alloiopleurus have 20–29 serrae on the last dorsal-fin ray, partially overlapping the serrae counts given to distinguish P. baolacensis and P. brevispinus . Distribution. Poropuntius alloiopleurus is found in the Song Hong ecoregion.