Acantopsis rungthipae, Boyd & Nithirojpakdee & Deein & Vidthayanon & Grudpan & Tangjitjaroen & Pfeiffer & Randall & Srisombat & Page, 2017

Boyd, David A., Nithirojpakdee, Patchara, Deein, Gridsada, Vidthayanon, Chavalit, Grudpan, Chaiwut, Tangjitjaroen, Weerapongse, Pfeiffer, John M., Randall, Zachary S., Srisombat, Tippamas & Page, Lawrence M., 2017, Revision of the horseface loaches (Cobitidae, Acantopsis), with descriptions of three new species from Southeast Asia, Zootaxa 4341 (2), pp. 151-192 : 173-176

Acantopsis rungthipae new species, Boyd, Nithirojpakdee, and Page

Piebald Horseface Loach

( Fig. 14 )

Holotype. THNHM F0013610, 107.4 mm SL female (ex. UF 235976), Thailand, Welu River drainage, Chanthaburi Province, Khlung District, Khen Creek , tributary of Trok Nong River , off Rt. 3277, 12.537N, 102.244E, 30 January 2014, Nithirojpakdee, J. et al.

Paratypes. Thailand: Welu River drainage: same locality and date as holotype: UF 235976 (6, 89.9–119.7 mm SL) ; ZRC 55596 (2, 93.2–111.6 mm SL); NIFI 5102 (2, 94.2–118.0 mm SL). Tapi River drainage: ANSP 179976 (1, 119.0 mm SL), Krabi / Surat Thani Provinces, Ipan River , trib. of Tapi River , on Rt. 4035, 25 km NE of Ao Luek, 08.623N, 98.980E, 22 February 2001, M. H. Sabaj and M. Hardman . INHS 93550 (1, 109.0 SL) same locality and date as ANSP 179976 .

Diagnosis. Acantopsis rungthipae differs from all other species of Acantopsis ( Table 4) by combination of no exposed labial barbels, usually distinct small black spot on upper margin of caudal-fin base, 0–1 row of large spots on side of head, no large black spots on dorsal or caudal fins, no black specks beneath midlateral row of black spots (rarely present), usually 9½ branched dorsal rays and 10 pectoral rays, 10–20 dark saddles along dorsal midline, 9– 17 black spots along side of body, 41–43 total vertebrae, body depth 9.0–14.2% SL, body width 5.3–10.3% SL, caudal-peduncle length 11.5–16.1% SL.

Comparisons. Acantopsis rungthipae is distinguished from all species of Acantopsis except A. ioa by having no labial barbels. It is distinguished from A. ioa by usually having a distinct small black spot on upper margin of caudal-fin base, 9–17 (vs. 13–21) black spots along side of body, and 41–43 (vs. 46–48) total vertebrae ( Fig. 15 ). It further differs from A. dinema by having large dark spots on side of head, usually lacking conspicuous row of black specks beneath midlateral row of black spots, having usually 9½ (vs. 10½) branched dorsal rays, a distinct small black spot (vs. no spot) on upper margin of caudal-fin base, and usually 4–6 faint, narrow bands (vs. no bands) on caudal fin. It further differs from A. octoactinotos by having usually 9½ (vs. 8½) branched dorsal rays, large dark spots on side of head, usually 10 pectoral rays. It differs from A. spectabilis and A. thiemmedhi in lacking conspicuous black bands on the anal and paired fins and spots or blotches on the caudal fin. It further differs from A. thiemmedhi in lacking a large black blotch on the tip of the anterior rays of the dorsal fin and in having usually 9½ (vs. 10½) branched dorsal rays, and from A. dialuzona by lacking a well developed ocellus on the margin of caudal-fin base and having usually 9½ (vs. usually10½) branched dorsal rays.

Description. As in description of genus; Tables 1, 2, 4. Head long (21.6–25.6% SL); snout long (54.7–68.7% HL); no exposed labial barbels; 9½, rarely 10½, branched dorsal rays; 10, rarely 9 or 11, pectoral rays; 29–31 abdominal + 11–12 caudal = 41–43 total vertebrae. Maximum SL = 203.2 mm, TL = 241.3 mm (CAS 238293).

Color. Dark spots in 1–2 rows on top of head, usually 1 row anteriorly, 2 posteriorly; dark spots on side of head usually in 1 row. Black line from eye to tip of snout. Ten–20 dark saddles along dorsal midline; 9–17 large dark spots or blotches along lateral line from head to caudal fin; small dark spots on upper side of body; no or few dark spots on lower side of body below midlateral row of dark spots. Dorsal fin with 2–3 faint bands, caudal with 4–5 faint bands; no dark upper and lower margins on caudal fin. Small bold black spot near upper margin of caudal-fin origin.

Live individuals yellowish brown dorsally, white below, with large black blotches dorsally and laterally on body; reddish brown streak on lower caudal margin; iridescent yellow on side of head and lower fins.

Sexual dimorphism. Males have a longer, ramified first branched pectoral-fin ray.

Etymology. This species is named in honor of Rungthip Plongsesthee, who was born on 27 May 1978 and died on 16 July 2014. “Kae” was a dear friend, close colleague, a Ph.D. student of Dr. F. W. H. Beamish at Burapha University, Bangsaen, Thailand, and an extremely enthusiastic ichthyologist who is greatly missed by her many friends.

Distribution. Acantopsis rungthipae is the most widespread and common species of Acantopsis in mainland Asia. It is known from the Tapi, Mae Khlong, Chao Phraya, Bang Pakong, and Welu River basins in Thailand, and the Mekong River basin in Thailand, Cambodia, Laos, and Vietnam ( Fig. 16 ).

Figures

FIGURE 14. Acantopsis rungthipae. (A) Lateral and dorsal VieWs, THNHM F 0013610, holotype, Welu RiVer, 107.4 mm SL. LiVe VieWs of (B) UF 235976, paratype, Welu RiVer, 91.7 mm SL, (C) UF 188117, Wang RiVer, 56.4 mm SL, (D) UF 188114, Songkhram RiVer, 90.6 mm SL, and (E) UF 236085, Tapi RiVer, 77.3 mm SL.

FIGURE 15. CT-scans of (A) Acantopsis rungthipae, THNHM F 0013610, holotype, 107.4 mm SL. (B) A. dinema, THNHM F 0013611, holotype, 100.7 mm SL. (C) A. ioa, UF 188136, 95.5 mm SL. CT-scans proVided by E. L. Stanley (UF).

FIGURE 16. Localities of specimens examined of Acantopsis rungthipae.