Pseudobagrus fui

Cheng, Jian-Li, López, Andrés & Zhang, E, 2009, Pseudobagrus fui Miao, a valid bagrid species from the Yangtze River drainage, South China (Teleostei: Bagridae), Zootaxa 2072, pp. 56-68 : 58-63

Pseudobagrus fui

( Figs. 1–5 ; Table 1 )

Pseudobagrus fui Miao, 1934: 217 (Chinkiang)

Pelteobagrus nitidus (nec Sauvage & Dabry de Thiersant, 1874): Ze, 1989: 238 (Chishui He, a tributary flowing to upper Yangtze River drainage); Li, 1994: 453 (in part: Leshan City in Sichuan Province and Nanchong County in Chongqing City).

Material examined. IHB 992344–56, 992361, (14), 60.7–112.5 mm SL; China: Chongqing City: upper Yangtze River drainage in Mudong Town of Ba’nan County; IHB 2519, (1), 98.4 mm SL, China: Sichuan Province: Min River of upper Yangtze River drainage in Leshan City; IHB 586052–3, 586017, (3), 112.4–124.9 mm SL, China: Sichuan Province: Jialing Jiang of upper Yangtze River drainage in Nanchong City; IHB 200520743, 581038, 584352, 583168–9 (5), 101.9–126.4 mm SL, China: Chongqing City: upper Yangtze River drainage in Mudong Town of Ba’nan County; IHB 586122–4, (3), 84.3–107.5 mm SL, China: Chongqing City: Jialing Jiang of upper Yangtze River drainage in Hechuan County; IHB 5343, (1), 120.5 mm SL, China: Chongqing City: Jialing Jiang of upper Yangtze River drainage in Beibei County; IHB 746490, (1), 117.8 mm SL, China: Sichuan Province: Tuo Jiang of upper Yangtze River drainage in Hushi Town of Luzhou City; IHB uncatalogued, (3), 111.3–133.8 mm SL, no precise data in Chongqing City; IHB 73VI 1493, 79III 0089, (2), 87.4–129.9 mm SL, China: Sichuan Province: Jinsha Jiang of upper Yangtze River drainage in Yibing City; IHB uncatalogued, (3), 104.4–110.5 mm SL, China: Chongqing City: upper Yangtze River drainage in Fuling County; IHB 6650207, (1), 112.5 mm SL, China: Guizhou Province: Wu River of upper Yangtze River drainage in Si’nan County; IHB uncatalogued, (1), 118.1 mm SL, China: Guizhou Province: Chishui He, a tributary of upper Yangtze River drainage in Maotai Town.

Diagnosis. Pseudobagrus fui differs from all other currently recognized congeners by having 27–33 analfin rays (vs. 12–25). It is part of a group of species identified by Ku et al. (2007) as being characterized by having a smooth anterior edge of the pectoral-fin spine and short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui , along with P. nitidus and P. vachelli , is distinguished from all other fork-tailed species of this group of species in having no fewer than 20 (vs. 14–19) branched anal-fin rays, the anal-fin base longer (vs. shorter) than the adipose-fin base and the posterior end of the anal-fin base posterior to (vs. anterior to) the vertical through the posterior end of the adipose-fin base. Pseudobagrus fui is further differentiated from P. nitidus in having a gas bladder without (vs. with) beaded lateral and posterior margins ( Fig. 2 ) and longer anal-fin base (length 30.1–35.9 % of SL vs. 23.6–30.3) and nasal barbel (length 24.2–43.6 % HL vs. 15.2–29.2; see Fig. 5 ), and from P. vachelli in having short maxillary barbels not extending to (vs. extending beyond) the base of the pectoral-fin spine.

Description. Morphometric data taken from 38 specimens (60.7–133.8 mm SL) are provided in Table 1 . See Figure 1a for general body appearance. Head depressed, broad, and covered with thin skin. Supraoccipital process slender, with evenly converging sides and forked tip, twice as long as nuchal plate, its width approximately one-fourth of its length. Nuchal plate triangular, naked, and in contact with supraoccipital process. Snout broadly rounded in dorsal view, longer than eye diameter. Interorbital space wide, and slightly convex. Eye large, elliptical, covered with thick membrane, antero-lateral in head, visible when viewed dorsally, but not ventrally.

Mouth inferior, small, transverse. Upper jaw protruded, gape narrower than interorbital space. Teeth villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary tooth plates broad, of equal width throughout. Dentary tooth plates arched, broadest at symphysis, narrowing laterally, of same width at symphysis as premaxillary tooth plate. Vomerine tooth plate unpaired, continuous across midline, slightly curved anteriorly, much narrower than premaxillary tooth plate. Gill opening wide, extending from posttemporal to beyond isthmus. Gill rakers 7 (3), 8 (6), 9 (20), 10 (6), or 11 (2).

Barbels in four pairs. Nasal barbel small, thread-like, extending slightly beyond midpoint, but not to posterior margin, of eye. Maxillary barbel slender, extending beyond gill membrane, but not to base of pectoral-fin spine. Mandibular barbels in two pairs, thick, short; inner barbel positioned in transverse row at level of posterior naris, extending slightly beyond anterior margin of eye; outer barbel rooted posterolateral to inner mandibular barbel, longer than eye diameter, just extending to posterior margin of eye.

Dorsal profile rising gradually from snout tip to dorsal-fin origin, then sloping evenly from there to posterior end of adipose-fin base and increasing gradually to dorsal origin of procurrent caudal-fin rays. Ventral surface of head flattened, ventral profile of body straight or slightly convex from pectoral-fin insertion to anal-fin origin, decreasing evenly from posterior end of anal-fin base to origin of ventral procurrent caudalfin rays. Lateral line complete, straight, mid-lateral in position. Vertebrae 5+40–41.

Dorsal fin with spinelet, spine and 7 soft, branched rays, inserted nearer to anal-fin origin than to snout tip. Dorsal-fin origin equidistant to pectoral-fin insertion and ventral to pelvic-fin insertion, closer to anal-fin origin than to snout tip. Spinelet flattened, with long, blunt distal tip. Dorsal-fin spine slender, with smooth anterior margin, distally slightly serrated posterior margin, longer than pectoral-fin spine, its length 1.0– 1.3 in HL. First dorsal-fin soft ray longest, surpassing tip of last ray. Distal margin of dorsal fin rays nearly straight. Nuchal plate triangular, with a pointed tip anteriorly.

Adipose fin inserted behind vertical through anal-fin origin, with convex distal margin for its entire length and a deeply incised posterior part to form rounded apex. Adipose-fin base short, equal to or slightly longer than half of anal-fin base length.

Pectoral fin with a spine and 7–8 soft, branched rays, inserted slightly anterior to vertical through posteriormost point of opercle, extending for three-fifths of distance to base of pelvic-fin spine. Pectoral-fin spine very stout, sharply pointed at tip, shorter than dorsal-fin spine, with a smooth anterior margin and 9–14 (mean 11.2) strong serrations along posterior margin. Pectoral-fin margin straight anteriorly, convex posteriorly. Cleithral process triangular with a sharp pointed tip, extending for half length of pectoral-fin spine.

Pelvic fin with 1 unbranched and 5 soft, branched rays, inserted slightly closer to vertical through posterior end of anal-fin base than to tip of snout, its origin anterior to vertical through depressed tip of dorsal fin. Tip of depressed pelvic fin extending beyond anal-fin origin. Pelvic-fin distal margin convex. Anus and urogenital opening nearer to anal-fin origin than to posterior end of pelvic-fin base.

Anal fin long, with 27–33 branched rays [27(1), 28 (8), 29 (4), 30 (13), 31 (4), 32 (6), 33 (2)], inserted anterior to adipose-fin origin. Anal-fin origin nearer to caudal-fin base than to tip of snout. Distal margin of anal fin convex; anterior rays shortest.

Caudal fin with 8+9 principal rays, deeply forked, middle rays less than half of longest rays; both lobes slightly pointed, with upper lobe slightly longer than lower one; procurrent rays extending anterior to fin base. Least depth of caudal peduncle behind posterior end of anal-fin base.

Coloration in formalin. Dorsal and lateral surfaces of head brown, and ventral surfaces yellow white. Neurocranium and opercle brown, preopercular region yellow white in smaller individuals, fading to more uniform brown in large individuals. Ground color of body yellow white, with a median dorsal brown stripe extending from anterior tip of nuchal plate to caudal- fin base and three brown rectangular blotches on lateral surfaces just above horizontal through distal tip of cleithral process arranged serially to form interrupted band running from posterior to pectoral fin insertion to caudal-fin base. First blotch beginning at anterior tip of nuchal plate and ending anterior to posterior base of pelvic fin, second blotch above anal fin and spanning roughly adipose-fin base and third blotch extending entire caudal peduncle length. Adipose fin brown, with a yellow anterodorsal margin and a slightly hyaline posterodorsal margin. Dorsal fin grayish brown for anterior two-thirds, rest of fin hyaline. Anal fin grayish and caudal fin with brown procurrent rays. Pectoral and pelvic fins grayish, except for hyaline first and last rays.

Distribution and conservation status. Pseudobagrus fui is so far known from the Yangtze River drainage, South China. The type locality is Chinkiang (now Zhenjiang), in the lower Yangtze River drainage of Jiangsu Province. It was reported as P. nitidus by Ze (1989) from the Chishui He of the upper Yangtze River drainage in Guizhou Province, and by Li (1994) from the upper Yangtze River drainage in Sichuan Province. The material we examined was collected from the main stem of the upper Yangtze River in Ba’nan and Fuling counties, Chongqing City; the Min River of the upper Yangtze River drainage in Jiading City, Sichuan Province; Jialing River of the upper Yangtze River drainage in Nanchong City, Sichuan Province, and Hechuan and Beibei counties, Chongqing City; Tuo River of the upper Yangtze River in Hushi Town of Luzhou City, Sichuan Province; Jinsha River of the upper Yangtze River in Yibing City, Sichuan Province; and also from Wu River of the upper Yangtze River in Si’nan County and Maotai Town, Guizhou Province ( Fig. 3 ).

Although P. f u i still survives in the Yangtze River drainage, its geographic range and population size seem to have decreased over time. Since its description by Miao (1934), no additional material of P. f u i has been secured from the type locality, the lower Yangtze River drainage in Zhenjiang City. In a recent monograph on freshwater fishes of Jiangsu Province, Ni and Wu (2007) did not document this species. Despite the persistence of P. f u i in the upper Yangtze River drainage, it exhibits a pronounced decline in population size during the past 20 years. This is clearly evidenced in the number of museum specimens of this species. Most museum specimens, if not all, were collected from the main stream of the upper Yangtze River and its tributaries during 1989–1999, and only a single specimen was collected from the main stream of the upper Yangtze River at Chongqing City in 2005.

Figures

FIGURE 2. Ventral view of gas bladder in: a. Pseudobagrus fui: IHB 5343, 120.5 mm SL, China, Chongqing City: upper Yangtze River drainage in Ba’nan County; b. P. nitidus: IHB 73 X 1628, 140.3 mm SL, China, Hunan Province: Dongting Lake linked to middle Yangtze River drainage in Yueyang City.

FIGURE 3. Map showing distribution of Pseudobagrus fui in China. Circles (localities of examined materials of P. f u i), triangle (type locality of the lost holotype), and the Yangtze River drainage (1) is identified by number.

FIGURE 5. Relationship between anal-fin base length and SL (a); and between nasal barbel length and HL (b) in P. fu i (●) and P. nitidus (Ο).

FIGURE 1. a. Pseudobagrus fui, IHB 992356, 103.0 mm SL, China, Chongqing City, upper Yangtze River drainage in Ba’nan County; b. P. nitidus, IHB 73 X 1850, 100.8 mm SL, China, Hu’nan Province, Dongting Lake linked to middle Yangtze River drainage in Yueyang City.

FIGURE 4. Scatterplot of the second and third principal components (PC 2 and PC 3) extracted from 31 morphometric characters of Pseudobagrus fui (●) and P. nitidus (Ο).

Tables

TABLE 1. Morphometric data for Pseudobagrus fui and P. nitidus.

Characters	Pseudobagrusfui (n=38) Range (mean±SD)	P. nitidus (n=142) Range (mean±SD)
Standard length	60.7–133.8 (103.6±17.3)	62.5–158.3 (102.4±21.2)
% SL
Body depth at anus	15.3–22.0 (18.6±1.5)	12.1–24.1 (17.2±2.2)
Body depth	18.4–25.1 (21.4±1.8)	15.9–27.2 (21.1±2.1)
Predorsal length	32.2–36.0 (34.6±0.9)	34.2–40.6 (37.4±1.0)
Preanal length	52.9–58.6 (55.9±1.4)	57.9–65.3 (61.4±1.4)
Prepelvic length	42.3–48.8 (46.0±1.5)	46.7–54.5 (49.8±1.4)
Prepectoral length	18.6–22.8 (20.4±0.9)	20.1–25.2 (22.3±0.9)
Dorsal spine length	15.5–25.6 (20.6±2.0)	15.8–24.3 (20.3±1.6)
Dorsal-fin length	21.5–29.2 (25.2±1.7)	20.7–28.2 (24.1±1.5)
Dorsal-fin base length	9.0–11.1 (10.0±0.7)	8.7–12.2 (10.7±0.6)
Pectoral spine length	15.5–21.9 (17.9±1.6)	15.8–23.9 (18.6±1.3)
Pectoral-fin length	18.6–24.7 (21.0±1.5)	17.7–26.5 (21.5±1.3)
Pelvic-fin length	12.5–16.9 (14.9±1.0)	12.8–17.9 (14.9±0.9)
Anal-fin base length	30.1–35.9 (32.9±1.3)	23.6–30.3 (26.3±1.2)
Adipose-fin height	3.5–5.7 (4.3±0.5)	3.6–6.9 (4.9±0.6)
Adipose-fin base length	11.6–18.4 (15.3±1.5)	11.2–19.3 (15.2±1.6)
Dorsal-adipose-fin distance	21.5–28.1 (25.3±2.0)	17.0–26.7 (22.3±1.6)
Adipose-caudal-fin distance	14.2–18.9 (16.6±1.1)	13.1–21.2 (16.5±1.1)
Caudal peduncle length	9.7–14.0 (12.2±1.1)	10.8–15.6 (13.0±1.0)
Caudal peduncle depth	6.9–8.9 (8.0±0.5)	6.1–9.6 (7.7±0.7)
Head length	20.2–23.7 (22.1±0.8)	21.0–26.2 (23.4±0.8)
% HL
Head depth	72.4–85.5 (79.3±3.7)	69.2–92.7 (79.4±4.9)
Head width	68.6–83.7 (74.0±3.8)	62.4–83.6 (71.0±4.7)
Snout length	29.0–37.3 (33.1±2.3)	29.4–39.4 (34.6±1.9)
Interorbital width	37.2–48.5 (42.4±3.0)	32.6–49.0 (40.8±3.8)
Eye diameter	19.8–30.2 (23.8±2.1)	16.6–26.7 (21.4±1.9)
Mouth width	26.7–39.2 (33.0±3.0)	26.8–46.6 (35.4±3.3)
Nasal barbel length	24.2–43.6 (35.1±4.5)	15.2–29.2 (21.8±2.7)
Maxillary barbel length	60.6–99.5 (70.5±7.0)	58.4–94.4 (76.7±6.7)
Inner mandibular barbel length	27.1–45.3 (35.8±3.3)	28.5–51.5 (39.1±4.3)
Outer mandibuler barbel length	18.7–31.7 (24.2±2.6)	16.9–32.3 (23.9±2.9)