Acantopsis, Dialuzona Van Hasselt, 1823

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 : 184

Key to the identification of species of Acantopsis

1 Conspicuous dark spots, blotches, or bands on caudal fin...................................................... 2

- No conspicuous dark spots, blotches, or bands on caudal fin.................................................... 3

2 Large black blotch on tip of anterior rays of dorsal fin; large black blotch on tip of each lobe of caudal fin, smaller black spots or bands in middle of caudal fin; 1 pair of labial barbels............................................ A. thiemmedhi

- No large black blotch on tip of anterior rays of dorsal fin; 2–3 black, irregular bands or blotches on caudal fin, darkest at extremity of lower lobe; 2–3 pairs of labial barbels................................................. A. spectabilis

3 Well developed ocellus on upper margin of caudal-fin base; 3 pairs of labial barbels........................ A. dialuzona

- No ocellus on upper margin of caudal-fin base (small black spot may be present); 0–2 pairs of labial barbels............. 4

4 Row of black specks beneath midlateral row of black spots from opercle to pelvic fin......................... A. dinema

- No row of black specks beneath midlateral row of black spots.................................................. 5

5 8½ branched dorsal rays; usually 9 pectoral rays; 2 pairs of labial barbels............................. A. octoactinotos

- 9½ branched dorsal rays, usually 10 pectoral rays; no labial barbels.............................................. 6

6 Small black spot on upper margin of caudal-fin base; 9–17 black spots along side of body; 41–43 total vertebrae..................................................................................................... A. rungthipae

- Usually no small black spot on upper margin of caudal-fin base; 13–21 black spots along side of body; 46–48 total vertebrae................................................................................................. A. ioa