Bagarius protos Zeng & Chen, 2025

Zeng, Yu-Yang, Pu, Xin-Rui, Lei, Hao-Tian, Oo, Thaung Naing & Chen, Xiao-Yong, 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), pp. 1123-1136 : 1123-1136

Bagarius protos Zeng & Chen sp. nov.

Figs 1 , 2 , Table 2

Bagarius yarrelli : Chu et al. 1990: 194–195 (Nujiang River, Yunnan, China, in part); Chu 1999: 117–118 (Nujiang River, Yunnan, China, in part); Chen 2013: 319 (Nujiang River, Nantinghe River, Yunnan, China, in part).

Bagarius sp. ‘Salween’ Ng & Kottelat, 2021: 141 (Salween River).

Type material.

Holotype. • KIZ 2024000178 , 319 mm SL; Sanjiangkou [三江口], Salween River [怒江], Longling County [龙陵县], Baoshan City [保山市], Yunnan Province [云南省], China, 24°25'05"N, 98°58'31"E; leg. Yu-Yang Zeng, Ling Wu & Cai-Xin Liu, May 2024.

Paratypes. • KIZ 2024000179 , 1 ex, 372 mm SL, other information same as holotype ; • KIZ 202400180 -181, 2 ex, 391–398 mm SL; Bizhai Township [碧寨乡], Salween River , Longling County, Baoshan City, Yunnan Province, China, 24°27'39"N, 99°00'48"E; leg. Yu-Yang Zeng, Ling Wu, Tao Qin & Jian-Bing Lvy, April 2024 ; • KIZ 2002009301 -9302, 2 ex, 393–403 mm SL, Daxueshan Township [大雪山乡], Nanting River [南汀河], Yongde County [永德县], Lincang City [临沧市], Yunnan Province, China, 24°01'02"N, 99°45'23"E, leg. Xiao-Yong Chen, 2002 ; • KIZ 2004015367 , 1 ex, 282.6 mm SL, Baihua Village [白花村], Salween River , Longyang District [隆阳区], Baoshan City, Yunnan Province, China, 24°50'05"N, 98°53'50"E leg. Zai-Yun Li, September 2004 ; • KIZ 2004015368 , 1 ex, 261.2 mm SL, Hongqiqiao Bridge [红旗桥], Salween River , Longyang District, Baoshan City, Yunnan Province, China, 24°43'58"N, 98°58'16"E, leg. Zai-Yun Li, September 2004 ; • KIZ 2004015372 , 1 ex, 289.9 mm SL, Sanjiangkou , Salween River , Longling County, Baoshan City, Yunnan Province, China, 24°25'05"N, 98°58'31"E, leg. Zai-Yun Li, September 2004 ; • KIZ 202410548 , 1 ex, 324 mm SL, Hehai Village [贺海村], Nanting River [南汀河], Gengma County [耿马县], Lincang City [临沧市], Yunnan Province, China, 23°34'27"N, 99°03'57"E, leg. Yu-yang Zeng, 2024 .

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 4 th – 6 th 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).

Description.

Morphometric data are shown in Table 2 . Head depressed, body subcylindrical, slightly compressed laterally at origin of anal fin. Dorsal profile rising uniformly from tip of snout to origin of dorsal fin, body depth at maximum at the origin of the dorsal fin, then sloping gently ventrally from origin of dorsal fin to end of caudal peduncle. Ventral profile flattened to base of anal fin, and then sloping gently dorsally from anal-fin base to caudal-fin base. Anus and urogenital openings located approximately 1 / 2 to 2 / 3 distance between end of pelvic-fin base and origin of anal-fin ray. Skin keratinized, with tubercles of various sizes on both sides of body; larger tubercles sparsely placed longitudinally along dorsal surface of head and dorsum. Lateral line complete, situated in midline of body. Vertebrae 23 + 20 = 43 * (4).

Head depressed and wide. Snout long, about half of head length. Anterior and posterior nares adjacent and separated. Gill opening broad, extending to isthmus. Dorsal surface of head covered by thick skin and ovoid tubercles. Eye small and ovoid; lateral margin of frontal not forming brow ridge.

Barbels in four pairs, including a pair of maxillary barbels, one pair of nasal barbels, and two pairs of mandibular barbels. Maxillary barbel subtended by large skin flap along posterior edge of proximal half of barbel; extending to middle of pectoral-fin base. Nasal barbel short, extending to posterior margin of posterior nares. Outer mandibular barbel extending beyond vertical line through eye. Inner mandibular barbel about 2 / 3 length of outer mandibular barbel.

Mouth inferior, with premaxillary dental bands partially exposed when mouth closed. Oral teeth cone-shaped, varying in size, and irregularly aligned on all tooth-bearing surfaces. Premaxillary teeth form a broad semilunar band, interrupted at midline.

Dorsal fin located at midpoint of body, with 6 branched fin rays; dorsal spine straight and strong, with smooth anterior and posterior margins, width 10.6–14.4 times its length. Adipose fin triangular, origin at vertical through or very slightly posterior to anal-fin origin. Caudal fin strongly forked, upper lobe longer than lower lobe, with i, 7, 8, i principal rays. Anal fin with iii or iv unbranched rays, 8–9 branched rays, anterior margin straight, posterior margin slightly concave. Position of pelvic-fin origin not settled, anterior, vertical, or posterior to posterior end of dorsal-fin base. Pelvic fin with i, 5 rays; tip of adpressed fin beyond anus, rarely reaching anal-fin origin. Pectoral fin with I, 11, I, 12, I, 13 rays; posterior margin slightly concave. Pectoral-fin spine with filamentous extensions comparatively short, reaching anterior pelvic-fin base. Spine with smooth anterior margins and serrated posterior margins.

Coloration.

In 75 % ethanol: dorsal and ventral surfaces of head and body gray, ventral surfaces light yellow. Long-term preserved specimens dark yellow overall. Three dark brown saddles below dorsal fin, below adipose fin, and on posterior half of caudal peduncle extending to base of caudal fin, respectively. Dorsal fin ash gray, dorsal-fin base brown. Pectoral fins gray with light posterior margins. Pelvic fin gray with an inconspicuous brown band. Anal fin ash gray, with brown base and a brown band. Caudal fin light gray. Head, body, and each fin with irregularly scattered small dark spots. The gray parts in 75 % ethanol show grayish yellow when alive.

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).

Distribution and ecology.

The new species is distributed in the mainstream of the Nujiang River and the Nanting River in China (Figs 3 , 8 ), also expected to occur on the Salween River in Myanmar and Thailand.

Notes on habits.

Bagarius protos used to be a local high-value food fish that lived in the mainstream of the Nujiang River. According to the locals, it can grow to over 100 kg. Local people used to catch B. protos by longline fishing, using Corydalidae larva or loach as bait and thick nylon rope as a line, tying one end to a boulder, and harvesting it on the next day. Even large individuals of B. protos over 10 kg are still attracted by Corydalidae larvae, showing the preference of B. protos for this prey.

Figures

Figure 1. Lateral (A), dorsal (B), and ventral (C) views of Bagarius protos sp. nov., KIZ 2024000178, holotype, 319 mm SL.

Figure 2. Living specimens of Bagarius protos sp. nov., paratype. KIZ 202410548, 324 mm SL.

Figure 3. Habitat of Bagarius protos, Bizhai Township, Longling County, Yunnan Province. Photo by Shu-Sen Shu.

Figure 8. Map showing collection localities of Bagarius protos and B. dolichonema.