Hongiastoma gen. nov.,  Angustistoma gen. nov.,  Scaphostoma gen. nov., S. annamense sp. nov. in Hoang, Jang-Liaw, Pham, Tran, Durand, Nguyen, Pfeiffer et Page, 2025.

Abstract

Molecular data from 35 of the 50 Acrossocheilinae species suggest that the species-level diversity in the subfamily has been overestimated, likely due to inadequate taxon and geographic sampling and reliance on morphological characters that vary intraspecifically. Three new genera, one resurrected genus, two resurrected species, and one new species are diagnosed and described herein. Nine synonyms of three valid species of Acrossocheilinae are recognized from the Yangtze, Xijiang, Song Hong, Annamite, and Mekong ecoregions in East and Southeast Asia. Thirty-two valid and six putative new species are indicated by molecular data and a key to the genera is provided. As more molecular and morphological data become available, additional taxonomic changes in this widespread and generally poorly known subfamily are likely.

Keywords: Angustistoma gen. nov., Cyprinidae, Hongiastoma gen. nov., molecular and morphological systematics, Scaphostoma annamense sp. nov., Scaphostoma gen. nov.

Order: Cypriniformes

Family: Cyprinidae Rafinesque, 1815

Subfamily: Acrossocheilinae Yang [Yang, et al. 2015.]

Hongiastoma Hoàng and Nguyễn, new genus

Type species: Varicorhinus argentatus Nguyễn and Đoàn, 1969. 

Lectotype RIAH 67, 147 mm, Suối Rút, Hòa Bình, Vietnam.

Etymology: The name is from the Vietnamese prefix hong- meaning the Song Hong or Red River where the type species occurs, and the Greek suffix -stoma meaning mouth and referring especially to the horny sharp sheath on the lower lip. Gender neuter.

Angustistoma Hoàng, new genus

Type species: Onychostoma elongatum (Pellegrin and Chevey, 1934): 340. 

Holotype: MNHN 1934-026, 142 mm, Ngòi-Thia—tributary of Red River, Nghĩa-Lộ, Yên-Bái, Vietnam.

Etymology: The name is from the classical Latin prefix angusti- meaning narrow, and the Greek suffix -stoma meaning mouth and referring especially to the horny sharp sheath on the lower lip. Gender neuter.

Scaphostoma Hoàng and Phạm, new genus

Type species: Gymnostomus lepturus (Boulenger, 1900): 961. 

Holotype: BMNH 1899.11.30.21, 159.2 mm, Five-fingers Mountains, Hainan Island, China.

Etymology: The name is from the classical Greek prefix σκαφό (scapho) meaning bow-shaped, and the Greek suffix -stoma meaning mouth and referring especially to the horny sharp sheath on the lower lip. Gender neuter.