Pareuchiloglanis gracilicaudata (Wu & Chen)

Li, Xu, Zhou, Wei, Thomson, Alfred W., Zhang, Qing & Yang, Ying, 2007, A review of the genus Pareuchiloglanis (Sisoridae) from the Lancangjiang (upper Mekong River) with descriptions of two new species from Yunnan, China, Zootaxa 1440, pp. 1-19 : 8-12

Pareuchiloglanis gracilicaudata (Wu & Chen)

( Fig. 5 )

Euchiloglanis gracilicaudata Wu & Chen, 1979: 294 –296 (Nangqian, Qinghai); Wu et al., 1981: 77.

Pareuchiloglanis gracilicaudata: Chu, 1981: 27 ; Chu, 1986: 41. Chu et al., 1990: 205 (Deqin and Weixi, Yunnan); Wu & Wu, 1992: 551 –552; Chen, 1998: 309 -310; Chu & Mo 1999: 169 (Nangqian, Qinghai; Deqin, Yunnan).

Material examined. All examined specimens are from the upper Lancangjiang, Yunnan, China. SWFC 9910098 (1; 166 mm SL), Yingpan, Lanping County. SWFC, 0004088-0004092 (5; 96–98 mm SL), Foshan, Deqin County. SWFC 0004051-0004059 (9; 91–125 mm SL), Kangpu, Weixi County. SWFC 0004065- 0 0 0 4077 (13; 84–116 mm SL), Yanwa, Weixi County.

Diagnosis. Characters distinguishing Pareuchiloglanis gracilicaudata from P. abbreviatus , P. kamengensis , P. m y z o s t o m a and P. prolixdorsalis are summarized in Table 1 . Morphometric and meristic data are in Table 3 . A species of Pareuchiloglanis with the following unique combination of characters: adipose-fin base not confluent with caudal fin (vs. confluent); premaxillary tooth patches appear joined (vs. separate); lower lip connected to base of maxillary barbel by skin flap, without sulcus between them (vs. not connected, with sulcus); branched caudal-fin rays 7 upper + 8 lower (vs. 6+7); dorsal fin i-5-6 (vs. i-7); anal fin ii-3-4 (vs. ii-8); distance between pelvic-fin origin to anal-fin origin shorter than distance between pelvic-fin origin to mouth (vs. equal); pectoral fin not reaching pelvic-fin origin (vs. reaching or extending beyond); pelvic fin reaching anus (vs. not reaching); origin of pelvic fin opposite end of dorsal-fin base (vs. posterior to end of dorsal-fin base); anus midway between anal-fin origin and posterior end of pelvic-fin base (vs. nearer to posterior end of pelvic-fin base or nearer to anal-fin origin); anal-fin origin midway between posterior end of pelvic-fin base and caudal-fin base (vs. nearer to posterior end of pelvic-fin base or caudal-fin base); snout length 58.3– 81.3% HL; caudal peduncle depth 3.5–6.0% SL.

Pareuchiloglanis gracilicaudata is distinguished from P. gongshanensis , P. f e a e, P. k a m e n g e n s i s and P. macropterus by a combination of the following characters: premaxillary tooth patches appear joined with median indentation (vs. separate) ( Fig. 2 A); lower lip connected to base of maxillary barbel by skin flap, and without sulcus between them (vs. not connected, with sulcus) ( Fig. 3 A). It differs from P. abbreviatus and P. anteanalis by its shorter pectoral fin, pectoral fin not reaching origin of pelvic fin (vs. reaching), and differs from P. feae , P. poilanei , P. sichuanensis and P. tianquanensis by its adipose-fin base not being confluent with caudal fin (vs. confluent). Pareuchiloglanis gracilcaudata differs from P. abbreviatus and P. prolixdorsalis by having 7+8 branched caudal-fin rays (vs. 6+7). It differs from P. songmaensis by having fewer fin rays, dorsal fin i-5, anal fin ii-3-4 (vs. i-7, ii-8). It differs from P. longicauda and P. s i n e n s i s by having origin of pelvic fins opposite end of dorsal-fin base (vs. posterior to end of dorsal-fin base). It differs from P. abbreviatus , P. anteanalis , P. f e a e, P. longicauda , P. nebulifer and P. rhabdurus by having origin of anus midway between posterior end of pelvic-fin base and anal-fin origin (vs. nearer to anal-fin origin or posterior end of pelvic-fin base). It differs from P. kamengensis , P. macrotrema , P. nebulifer , P. rhabdurus and P. robusta by having origin of anal fin midway between posterior end of pelvic-fin base and caudal-fin base (vs. nearer posterior of pelvicfin base or caudal-fin base). It differs from P. m y z o s t o m a by pelvic fin reaching anus (vs. not reaching) and longer snout, 58.3–81.3% HL (vs. 47.2–51.8% SL). Pareuchiloglanis gracilicaudata differs from P. songdaensis by having distance between pelvic-fin origin to anal-fin origin shorter than distance between pelvic-fin origin to mouth (vs. equal) and more slender caudal peduncle.

Distribution. Known only from the upper Lancangjiang [Mekong] drainage ( Fig. 4 ).

Figures

FIGURE 2. Ventral view of premaxillary tooth band. A, premaxillary tooth patches appear joined with a shallow median indentation (Pareuchiloglanis gracilicaudata, SWFC 0 0 0 4052, 110 mm SL); B, premaxillary tooth patches appear separate with a deep median indentation (Pareuchiloglanis kamengensis SWFC 0 411001, 149 mm SL); C, premaxillary tooth patches separate (Oreoglanis setiger, SWFC 0 411019, 94.4 mm SL).

FIGURE 3. Ventral view of maxillary barbel and lower lip. A, maxillary barbel and lower lip connected directly (Pareuchiloglanis gracilicaudata, SWFC 0 0 0 4052, 110 mm SL); B & C, maxillary barbel and the lower lip interrupted by an obvious sulcus (s) (B, Pareuchiloglanis kamengensis, SWFC 0 411001, 149 mm SL; C, Oreoglanis setiger, SWFC 0 411019, 94.4 mm SL).

FIGURE 4. Map showing distributions of species of Pareuchiloglanis in the Lancangjiang (upper Mekong River) and Honghe (Red River or Song Hong) drainages.

FIGURE 5. Pareuchiloglanis gracilicaudata, SWFC 0 0 0 4051, 115 mm SL; Kangpu, Weixi county, Yunnan province, China. Dorsal, lateral and ventral views.

Tables

TABLE 3. Counts and proportional measurements of Pareuchiloglanis gracilicaudata, P. myzostoma and P. prolixdorsalis (italic and bold indicate a diagnostic difference between species).

	P. gracilicaudata	P. myzostoma
Locality Number of specimens	Lanping: Yingpan; Deqin: Fos- han; Weixi: Kangpu, Yanwa 28	Lanping: Lamahe (syn- Lanping: Yingpan type) 10 1
Dorsal-fin rays	i-5	i-5-6 i-5
Pelvic-fin rays Pectoral-fin rays	i-5 i-14-16	i-5 i-5 i-14-15 i-14
Anal-fin rays	ii-3-4	ii-4 ii-4
Branched caudal rays in% standard length Predorsal length	7+8 mean range S.D. 35.8 33.3–39.2 1.66	7+8 7+8 mean range S.D. range 36.4 34.3–38.4 1.51 36.0
Length of dorsal-fin base Body depth	12.5 10.8–14.3 0.83 14.4 11.5–17.6 1.56	10.8 9.2–12.7 1.06 9.1 10.8 9.6–13.6 1.34 13.1
Head length	21.9 17.8–26.4 2.50	27.3 26.3–28.6 0.77 22.6
Maximum head width Caudal peduncle length	24.1 21.0–28.4 1.48 20.6 18.6–22.8 1.16	24.2 22.1–26.3 1.30 23.7 18.3 17.0–19.3 0.83 17.6
Caudal peduncle depth	4.7 3.5–6.0 0.60	5.3 5.0–5.9 0.27 5.3
Length of dorsal base to adipose Length of pre-adipose to snout	18.3 13.9–22.0 2.07 62.9 60.0–66.7 2.10	14.5 10.7–26.2 4.44 14.4 60.3 57.9–63.0 1.52 59.9
Dorsal-fin length	19.3 17.7–20.8 0.87	17.7 15.6–19.5 1.18 18.1
Pectoral-fin length Pelvic-fin length	23.5 21.5–27.1 1.08 18.1 15.6–20.0 1.07	25.4 24.3–27.5 0.87 25.1 17.9 16.2–19.1 0.90 19.5
Anal-fin length	13.3 9.9–17.2 1.52	13.3 12.1–14.8 0.84 13.9
Length of anal-fin base Caudal-fin length	6.3 4.1–7.8 0.72 14.8 13.1–16.8 0.92	6.7 5.6–7.6 0.72 6.4 17.3 13.9–19.7 2.02 16.8
Length of adipose-fin base i n% head length Snout length	28.7 20.5–34.4 2.9 70.3 58.3–81.3 7.39	31.1 28.2–33.6 1.50 32.4 48.9 47.2–51.8 1.68 52.0
Eye diameter	8.4 5.6–12.4 1.82	6.7 5.7–7.2 0.50 6.4
Interorbital width in% Pt-Pl length Length of pectoral fin in% Pl-A length Length of pelvic fin in% length of caudal peduncle	28.5 21.2–35.3 4.02 85.7 72.6–105.7 8.13 59.7 51.4–69.7 5.37	23.6 21.4–25.2 1.24 26.6 90.8 83.2–100.0 6.58 78.4 63.9 55.4–72.5 5.21 55.3
Depth of caudal peduncle	22.7 16.6–30.1 3.06	29.2 25.4–31.0 1.72 30.3
continued.
Locality	P. prolixdorsalis Jinghong : Xiaonuoyou	Zhenyuan: Donggualin
Number of specimens Dorsal-fin rays	5 i-5-6	1 i-5