Sinocyclocheilus brevifinus, Li, Jie, Li, Xinhui & Mayden, Richard L., 2014

Li, Jie, Li, Xinhui & Mayden, Richard L., 2014, Sinocyclocheilus brevifinus (Teleostei: Cyprinidae), a new species of cavefish from Guangxi, China, Zootaxa 3873 (1), pp. 37-48 : 40-43

Sinocyclocheilus brevifinus sp. nov.

Figure 2

Holotype: PRFRI 201205001, Female, 131.5 mm TL, 111.1 mm SL; Maohedong Village, Wanggao Town, Hezhou City, Guangxi Zhuang Autonomous Region, South China; Zhujiang Basin, Hejiang drainage (24° 36′ 2.2″ N, 111° 28′ 12″ 'E); 15 May 2012; J. Li.

Paratypes: PRFRI 201205002–201205005, 82.2–126.5 mm TL, 67.2–104.2 mm SL; data same as holotype.

Diagnosis. Distinguished from many species of Sinocyclocheilus in having eyes present, nape not elevated to form a slight, moderate, or strongly developed hump, and notably lacking any anteriorly directed rounded or blunt, unifed or bifed projections from nape or posterior portion of cranium. Distinguished from all other similar species of Sinocyclocheilus , except S. jii , S. guilinensis , S. huangtianensis , S. gracilis , S. yishanensis Li & Lan, and S. macrolepis Wang , by the last unbranched ray of the dorsal fin being soft, absence of serrations along the posterior margin of last unbranched soft ray of the dorsal fin (vs. serrated in others). Diagnosed from S. macrolepis in having scales of lateral line significantly larger than those in scale rows immediately above and below lateral line (vs. of nearly same size), and from S. yishanensis in having fewer lateral-line scale rows (46–48 vs. 57–69). Distinguished from S. jii , S. huangtianensis and S. guilinensis in having a smaller eye diameter (3.4–5.0 % SL vs. 5.7–8.6 % SL), shorter dorsal fin (distal tip of depressed dorsal fin not reaching vertical from origin of anal fin vs. terminal reaching or beyond origin of anal fin), shorter pelvic-fin (depressed fin far from the anus-fin 15.0–17.8% SL vs. reaching anus-fin 17.4–20.2 % SL) and short maxillary barbels (tip of barbels not reaching edge of operculum vs. extending beyond edge of operculum). Sinocyclocheilus brevifinus is distinguished from S. jii in having more gill rakers (9–12 vs. 6–7), from S. guilinensis in having more circumpeduncular scale rows (44–46 vs. 34–36), and from S. huangtianensis in having fewer lateral-line scale rows (46–48 vs. 52–59). It can be distinguished from S. gracilis in having more circumpeduncular scale rows (44–46 vs. 36–38), a shorter caudal peduncle (19.1–22.9 % SL vs. 27.6–31.2% SL), shorter head (23.0–27.3 % SL vs. 27.6–31.2% SL), and flanks with black spots (vs. without black spots). Diagnostic features are also provided in Table 1 and in Principal Component Analysis. Images of S. brevifinus and four similar species are provided in Figures 2 and 3 .

Description. General body features and physiognomy are provided in Figure 2 . Meristic data and proportional measurements are provided in Table 2 . Length of specimens of Sinocyclocheilus brevifinus range from 82.1–131.5 mm TL or 67.2–111.1 mm SL.

Body compressed. Greatest body depth immediately anterior to origin of dorsal fin. Head short and semi-coneshaped. Snout wide and flat; prominent anteriorly; snout length less than length between posterior margin of eye and posterior edge of operculum. Nares located between tip of snout and anterior edge of eye. Anterior nares rimmed with fleshy flap, forming a complete tube; posterior nares elliptical. Two pairs of barbels; insertion of maxillary barbels anterior to anterior nares. Barbels short, extending just posterior to eye; maxillary barbels short, not extending to the posterior margin of operculum. Eye small, round. Mouth subterminal and cambered. Upper jaw slightly longer than lower jaw. Lips simple. Opercular opening large and membranes connected at isthmus.

Origin of dorsal fin midway between snout and caudal-fin base; origin slightly closer to caudal fin base and posterior to vertical from insertion of pelvic fin. Depressed dorsal fin terminating anterior to vertical from anal-fin origin. Last simple dorsal-fin ray soft and without serrations along posterior margin. Pectoral fins short; depressed fins not extending to insertions of pelvic fins. Pelvic fins short, depressed fins not extending to anus. Anal fin short, its origin midway between insertion of pelvic fin and caudal-fin base. Caudal fin bifurcate.

Body covered by moderately small scales; lateral line complete and scales perforated; lateral-line scales larger than those above and below lateral line. Lateral line almost straight from operculum to the caudal-fin base except for being slightly reflexed dorsal to pectoral fin. Breast and venter scaled.

Lateral-line scales 46–48 (mean =46.9; SD =0.8). Scale rows between lateral line and dorsal fin 22–23 (mean =22.4; SD =0.5). Scale rows between lateral line and pectoral fin 15–16 (mean =15.6; SD =0.5). Scale rows around caudal peduncle 44–46 (mean =44.8; SD =0.8). Gill rakers on first arch 9–12 (mean =10.1; SD =1.1). Dorsal-fin rays iii-7. Pectoral-fin rays i-13. Pelvic-fin rays i-8. Anal-fin rays iii-5. Vertebrae 35–38 (mean =36.2; SD =1.2). Pharyngeal teeth three rows: 2, 3, 4-4, 3, 2.

Dorsum of live specimens dark gray; venter whitish, and flanks with dark blackish-gray blotch-like spotting above and below lateral line; blotches sometimes fused to form horizontal and dark stripe both above and below lateral line; however, large blotches remain distinct from interconnecting and narrower darkened areas ( Fig. 2 ). In life and shortly after fixation many flank scales are argent in appearance, creating a metallic fleck appearance. Color of dorsal, pectoral, and caudal fins approaching dark gray; pelvic and anal fins slightly opalescent. Fixed and preserved specimens dorsum gray with white abdomen.

Etymology. brevifinus is a noun in apposition combining Latin brevis for "short" and latinized "fin" as finus. Name is in reference to the short fins of the species.

Distribution, habitat, and associated species. This species has only been found from an underground river system in Maohedong Village, Wanggao Town, Hezhou City, Guangxi, China ( Figs. 4 , 5 ). The underground river drains into the Hejiang River, which in turn flows into the Xijiang River, the longest tributary of the Pearl River Basin. On 12 May 2012, water parameters (temperature, conductivity, total dissolved solids, dissolved oxygen, pH, and Oxidation-Reduction Potential) at the site of collection were 23.6 °C, 0.423 us/cm, 0.275 mg /L, 7.9 mg /L, 7.12, and 143.9 mV, respectively. Silurus cochinchinensis Cuvier & Valenciennes and Zacco platypus Temminck & Schlegel were also collected at this location.

Figures

FIGURE 2. Sinocyclocheilus brevifinus sp. nov. a) Lateral view of holotype, PRFRI 2012001, 111.1 mm SL. China, Guangxi Zhuang Autonomous Region, Wanggao, Zhujiang Basin, Hejiang drainage; " b) Live specimen of " Sinocyclocheilus brevifinus sp. nov. from same locality.

FIGURE 3. Species presumed to be closely related to Sinocyclocheilus brevifinus sp. nov. a) S. guilinensis b) S. jii c) S. huangtianensis d) S. gracilis.

FIGURE 4. Distribution of Sinocyclocheilus brevifinus sp. nov. and related species. ▲ S. brevifinus sp. nov., + S. macrolepis, ★ S. yishanensis, ● S. jii, ■ S. huangtianensis, • S. guilinensis, and ♦ S. gracilis

FIGURE 5. Type locality of Sinocyclocheilus brevifinus. Upper, general area near outlet. Lower, spring fed area where species was found.

Tables

TABLE 2. Morphometric data as percentage of Standard Length for Sinocyclocheilus brevifinus sp nov. (n = 9).

Measurements	Holotype	Paratypes (n=8)	Mean ±SD
		Range
Standard Length (mm)	111.1	67.2–104.2	84.1±11.9
Percent Standard Length
Body depth	27.1	22.8–27.1	25.1±1.5
Predorsal length	47.7	47.4–54.9	50.3±2.4
Length of dorsal-fin base	11.5	8.6–12.6	11.6±1.3
Length of dorsal fin	18.1	17.8–23.0	20.2±1.4
Preanal length	69.5	67.2–73.8	71.3±2.3
Length of anal-fin base	8.8	7.6–8.7	8.3±0.6
Length of anal fin	13.9	13.9–19.8	17.3±1.9
Prepectoral length	23.3	22.9–26.2	24.7±1.0
Length of pectoral-fin base	3.0	2.9–3.5	3.2±0.2
Length of pectoral fin	19.9	18.3–21.1	19.8±0.9
Prepelvic length	47.3	47.3–50.9	49.0±1.3
Length of pelvic-fin base	3.3	3.5–4.4	3.8±0.3
Length of pelvic fin	15.1	15.0–17.8	16.8±1.4
Caudal-peduncle length	22.9	19.1–22.9	21.2±1.4
Caudal-peduncle depth	15.6	12.1–15.6	13.5±1.1
Head length	24.5	23.0–27.3	25.6±1.3
Head depth	14.3	12.1–16.6	14.5±1.1
Head width	15.4	10.9–15.4	13.2±1.3
Snout length	7.7	6.5–9.4	7.5±0.9
Eye diameter	3.4	3.4–5.0	4.0±0.4
Interorbital width	9.4	7.4–9.9	8.7±0.9
Prenaris length	4.9	3.4–5.4	3.9±0.8
Width between poster nares	5.6	4.7–6.6	5.7±0.6
Upper jaw length	6.6	4.1–6.6	5.4±1.0
Lower jaw length	5.8	3.9–5.8	5.0±0.8
Mouth width	7.6	4.6–8.2	6.4±1.2
Maxilla barbel length	10.3	9.2–12.8	10.6±1.4
Rictal barbel length	10.0	9.3–13.9	11.5±1.7