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| Vanmanenia duci Dang, Duong, Li, Nguyen & Tran, 2024 |
Abstract
Recent ichthyofauna surveys in Phia Oac-Phia Den National Park, Vietnam, yielded 16 specimens of loach representing the genus Vanmanenia. These specimens were uniform in morphology and distinct from known species, leading to the designation of a new species, Vanmanenia duci sp. nov. This species is distinguished from congeners by the following combination of characters: pectoral fin: I, 15; pelvic fin: I, 8; lateral line scales 77–83; the distance from the anus to the posterior insertion of the pelvic fin being greater than from the anus to the anal fin origin; a lateral black stripe from the gill opening to the caudal fin base; a black spot at the caudal fin origin equal to the eye diameter; and a lower lip with three large papillae, with the middle one being larger. The new species differs from Vanmanenia caldwelli (Nichols, 1925) by its mouth soft-tissue structures and lower morphometric values and from Vanmanenia ventrosquamata (Mai, 1978) and Vanmanenia caobangensis Nguyen, 2005 by having more lateral line scales and lower body depth. Additionally, Vanmanenia duci sp. nov. has a larger eye and wider interorbital space compared to other species in Vietnam. This species is found in the Red River basin in Vietnam and the Bang Giang River flowing into China, indicating high potential for freshwater fish diversity in these river systems.
Keywords: Bang Giang River, Gam River, new species, northern Vietnam, taxonomy, Vanmanenia
Family Gastromyzontidae
Genus Vanmanenia Hora, 1932
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| Vanmanenia duci sp. nov., HNUE-F00293, SL = 47.6 mm in Phia Oac-Phia Den National Park, Cao Bang Province, northern Vietnam. |
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| Aquarium photograph of Vanmanenia duci sp. nov. (HNUE-F00293, 47.6 mm SL) from northern Vietnam. |
Vanmanenia duci sp. nov.
Diagnosis: Vanmanenia duci sp. nov. can be distinguished from congeners by following combination of characters: pectoral fin rays: I, 15; pelvic fin rays: I, 8; lateral line scales: 77–83; anus farther posterior insertion of pelvic fin than to anal fin origin, caudal peduncle depth approximately as caudal peduncle length (8.2%–8.5%), distance from pelvic fin to pectoral fin (39.1%) larger than distance from pelvic fin to anal fin (29.8%). It has a broad midlateral black stripe running from behind head to caudal-peduncle base. Black dotted stripe stretching from base of pectoral fin to posterior end of anal fin. Lower lip with three large papillae; median wider than two lateral ones. Rostral fold divided into three triangular lobules of same size. Distinct black dot at base of pelvic and pectoral fins, and fleshy black protrusion in pelvic fin base.
Etymology: The specific name is in honor of Vietnamese ichthyologist, Prof. Nguyen Huu Duc, who had spent his whole life studying freshwater fishes in Vietnam.
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| Habitat of Vanmanenia duci sp. nov., in the Gam River (DO.02) and Bang Giang River (DO.05, DO.07) in Phia Oac-Phia Den National Park, northern Vietnam. |
Huong Thi Thanh Dang, Huyen Thi Duong, Fan Li, Huy Quang Nguyen and Hau Duc Tran. 2024. A New loach Species of the Genus Vanmanenia (Actinopterygii: Cypriniformes: Gastromyzontidae) from hill streams of Vietnam. Acta Ichthyologica et Piscatoria. 54: 177-187. DOI: doi.org/10.3897/aiep.54.121328
