Black Lizard Loach

Diagnosis. Member of Balitoropsis as defined by Randall and Page (2015). Balitoropsis zollingeri is distinguished from B. ophiolepis (Table 3) by mostly black caudal-fin with 1 – 3 black bands on distal extremity of white upper lobe vs. hyaline with multiple black bands; caudal-peduncle depth 8.0 – 9.3 % vs. 4.0 – 5.1 % SL; body depth 13.6 – 17.6 % vs. 9.2 – 11.9 % SL; 42 – 46 vs. 48 – 55 total lateral-line scales; and 17 – 20 vs. 13 – 14 circumpeduncular scales. TABLE 3. Characters distinguishing species of Balitoropsis. Number of specimens examined in parentheses. Description. Dorsal, lateral, and ventral views of B. zollingeri are shown in Figure 5. Measurements and meristic counts are given in Table 2. Body arched predorsally and flattened ventrally. Head with two rows of prominent tubercles longitudinally between nares. Eyes dorsolateral, shorter than interorbital width. Rostral cap large. Dorsal-fin origin anterior to or at pelvic-fin origin. Pectoral fin reaching about midway between pectoral-fin insertion and pelvic-fin origin. Pelvic fin reaching far past anus. Anus closer to pelvic-fin base than to anal-fin origin. Anal fin not reaching caudal-fin base. Axillary pelvic lobe absent. Caudal fin forked with rounded lobes; lower lobe longer. Dorsum with large keeled scales; scales on ventral surface without keels, deeply embedded between pectoral and pelvic fins. Total lateral-line scales 42 – 46, predorsal scales 13 – 15, circumpeduncular scales 17 – 20. Scales above and below lateral line 5 – 7 / 5 – 6, respectively. Scales below lateral line to pelvic-fin origin 5 – 6. Modal fin-ray counts (variation given in Table 2): dorsal iii, 8 ½; anal ii, 5 ½; pectoral iv, 10, i; pelvic ii, 8; total caudal 17. Mouth (Fig. 6 A) inferior; lips with tiny unculi, continuous around corners of mouth. Distal-lateral extension of lower lip uncommon. Fleshy pad present between lateral halves of lower lip. Rostral and post-labial grooves present. Two pairs of rostral barbels, one pair of maxillary barbels. Barbels with tiny unculi, rostral barbels in close proximity to each other. Medial-rostral barbels separated at base. Lateral-rostral barbel longer than medial-rostral barbel, reaching to maxillary barbel. Maxillary barbel reaches horizontally to vertical at anterior orbital rim. Under surface of head covered in small tubercles; branchiostegal membrane united to isthmus with small central furrow. Color in 70 % ethanol (Fig. 5): Dorsally light-dark brown with dark brown mottling. Some specimens dark overall with dorsal saddles hard to differentiate. Six brown-black dorsal saddles usually present. 1 st saddle between supraoccipital and 2 nd saddle; 2 nd saddle from anterior to dorsal-fin to just behind origin of fin; 3 rd saddle spans most of dorsal-fin length; 4 th saddle between distal extremity of dorsal-fin to just past anal-fin origin; 5 th saddle spans most of anal-fin length; 6 th saddle at caudal-fin base. In some individuals, 5 (5 th and 6 th saddle fused) or 7 (extra saddle between 2 nd and 3 rd saddles) saddles present. Brown-black triangular blotch between posterior orbital margins and supraoccipital. Venter cream; heavily stippled posterior to anal-fin origin, less so between anal and pectoral fins, stippling becoming patchy near head. Undersurface of head heavily stippled dark brown. Barbels stippled brown with hyaline tips. Lips and fleshy pad lightly stippled brown. All fins dark brown-black; sometimes 2 – 3 black bands on dorsal fin. Caudal fin mostly black; 1 – 3 small black bands on clear portion of upper lobe, white tips on upper and lower lobes. Color in Life. Live large and small individuals shown in Figure 7. Both have similar color pattern with exception of orange infraorbital blotch in smaller individual. Head, body, and fins stippled black. Orange mottling on head, highlighting dorsal saddles, and on hyaline portions of fins. Large orange-red patch between pectoral fins on larger individual.