Sunday, March 12, 2023

[Ichthyology • 2023] Euchiloglanis nami • A New Species of Euchiloglanis Regan, 1907 (Siluriformes: Sisoridae) from Vietnam


Euchiloglanis nami  
 Tran, Nguyen, Dang, Nguyen & Nguyen, 2023


Abstract
 A new species of sisorid catfish of the genus Euchiloglanis is described from the Gam River, a tributary of the Red River in northern Vietnam. Euchiloglanis nami sp. n. differs from all the species placed in Euchiloglanis and Chimarrichthys by having elongated papilae on the ventral part of maxillary barbell. Euchiloglanis nami is distinguished from E. longibarbatus by having a wider premaxillary tooth band without indentation and the tip of the maxillary barbell reaching pectoral fin origin. The new species differs from E. davidi and E. kishinouyei by the depth of the caudal peduncle equal to 20.26–27.40 % of the caudalpeduncle length. It also differs from E. dorsoarcus by the anal-fin position being closer to the caudal-fin base than to the pelvic fin. From E. phongthoensis, it differs by the distance from the adipose-fin origin to the dorsal-fin insertion close to 50 % of the length of the adipose-fin base. In addition, E. nami differs from E. longus by having a wider premaxillary tooth band without indentation, shorter caudal peduncle (20.7 % SL), higher caudal peduncle depth (5.0 % SL), shorter distance between dorsal-fin insertion to adiposefin origin (14.8 % SL), shorter distance from snout to adipose-fin origin (57.4 % SL), shorter pelvic fins length (15.9 % SL) reaching the anus or a little beyond anus, longer adipose-fin base length (33.2 % SL) and narrower interorbital width (24.6 % SL). The new species is the first record of the genus Euchiloglanis in the Gam-Lo River system and is the third species in the genus from Vietnam. 

Key words: Euchiloglanis nami sp. n., new species, Glyptosterminae, Black River, Gam River

Euchiloglanis nami sp. n., HNUE-F00283, holotype, 142.3 mm SL; Phia Oac-Phia Den National Park; Cao Bang Prov., Vietnam. Dorsal, ventral and lateral views. Scale bar 10 mm.

Euchiloglanis nami sp. n., HNUE-F00283, holotype, 142.3 mm SL; Phia Oac-Phia Den National Park; Cao Bang Prov., Vietnam. Dorsal, ventral and lateral views.   Scale bar 10 mm.
Ventral profile of the head part of the holotype.
Ventral view of premaxillary tooth band of Euchiloglanis nami 
collected from the Gam River of the Red River, northern Vietnam.

Euchiloglanis nami sp. n.
 
Diagnosis. Euchiloglanis nami sp. n. can be distinguished from congeners by the following unique combination of characteristics: D. i, 6; A. i, 4; P. i, 15–16; C. 16; wider premaxillary tooth band without indentation (Fig. 4); elongate and threadlike maxillary barbell with pointed tip reaching to pectoral fin origin; elongated papilae ventral part of maxillary barbell; anal-fin origin closer to caudalfin base than to pelvic-fin insertion; distance from adipose-fin origin to dorsal-fin insertion close to 50% of length of adipose-fin base; depth of caudal peduncle equal to 20.26–27.40% of length of caudal peduncle; shorter dorsal-fin insertion to adipose-fin origin (12.05–15.90% SL); shorter caudal-fin length (11.53–13.42% SL); longer adipose-fin base length (31.81–35.74% SL); adipose fin not connected with caudal-fin base; pelvic fins reaching anus or a little beyond anus; narrower interorbital width (20.97– 29.45% HL).

Etymology. The specific name is in honour of the young ichthyologist and our best friend Mr. Chu Hoang Nam. The species name is a noun in genitive case. 


Hau Duc Tran, Duc Huu Nguyen, Huong Thanh Thi Dang, Huy Quang Nguyen and Nga Thi Nguyen. 2023. A New Species of Euchiloglanis Regan, 1907 (Actinopterygii: Sisoridae) from Vietnam. ACTA ZOOLOGICA BULGARICA [Acta Zool. Bulg.]. in press