| Diagnosis: |
Dorsal spines (total): 15-19; Dorsal soft rays (total): 112-132; Anal soft rays: 81-98; Vertebrae: 85-92. Diagnosis: 14+1 to 18+1 (median 16+1) dorsal spines; distance from anterior border of snout to last externally visible dorsal spine relatively short, 37.1-44.2% SL (m=40.9), decreasing with size; as a result origin of soft dorsal fin far anterior to origin of soft anal fin (Ref. 57415, 81678).
Description: 2 pre-opercular spines; 1 pre-orbital spine; origin of 1st dorsal spine always situated before posterior edge of pectoral fin, between (-8.6) and (-1.7)% HL [m = -5.4]; origin of soft dorsal fin far before origin of soft anal fin (Ref. 57415, 81678). Distance from anterior border of snout to last externally visible dorsal spine 37.1-44.2% SL (mean 40.9%), decreasing with size (Ref. 81678). Distance from anterior border of snout to last externally visible anal spine 51.2-56.8% SL (m=54.2), decreasing with size; post-anal length 47.9-51.8% SL (m=50.1), increasing with size, comparable to pre-anal length, 46.4-51.6% SL (m=48.9), decreasing with size; difference between number of soft dorsal fin rays and number of soft anal fin rays (+25)-(+34) (mean +31); 9-12 caudal fin rays; 6-7 predorsal vertebrae; 30-33 abdominal vertebrae; (+9)-(+12) in-between vertebrae; 54-61 caudal vertebrae (Ref. 57415, 81678).
Coloration: preserved specimens: uniformly light brown overall background colour; dorsal midline with a series of large, dark brown, rectangular spots, extending along dorsal, caudal and anal fin bases; dark brown lateral band originating at base of rostral appendage, passing through eye, above pectoral fin and continuing on lateral side of body and tail as a series of large rectangular or more X-like dark brown spots; spots sometimes contacting spots on dorsal midline and/or spots on basal part of unpaired fins; however, a few specimens have more uniformly coloured dark brown sides; lips, ventral surface of head, belly, abdomen and tail light brown, yellowish-white, with some darker parts; belly with large white spots surrounded by a darker brown network; overall background colour of dorsal, caudal and anal fins whitish (Ref. 57415, 81678). Dorsal and anal fin base with a series of large, dark brown, spots partially situated on tail; dorsal fin base light brown diminishing contrast between dark brown spots and background colour of fin; caudal fin with a vertical, dark brown band (Ref. 57415). Dorsal and anal fins with additional dark brown spots of irregular shape occasionally forming a band towards outer margin of fins; nevertheless, outermost part of unpaired fins remains white; pectoral fins whitish of overall background colour with several irregular shaped, dark brown spots forming a kind of network in some specimens; size-related colour pattern changes, especially a general darkening of unpaired fins; in addition, sometimes dark brown spots at base of anal fin contact dark brown band situated towards outer margin of fin resulting in a series of light brown, white spots at base of anal fin (Ref. 57415, 81678). Live specimens: colour pattern considerably variable (Teugels et al., 1992); Roberts&Travers (1986) reported a grey life colour for background or darker coloration on body and fins of some specimens; further, lighter areas on dorsal and anal fins were yellow or sometimes merely pale or colourless and round spots on abdomen were always yellow (Ref. 57415). |
| Biology: |
All type specimens were caught in the region of the rapids characterized by a swift current of crystal clear water flowing over a predominantly rock, stone or gravel substrate with small areas of coarse yellow sand; however, this species is also found in a wide variety of habitats such as turbid, sandy lagoons with a sluggish flow of water, heavily shaded, rocky or pebbly, clear swift streams, and exposed, pot-holed bedrock pools (Ref. 81678). Maximum reported TL was 271mm (Ref. 57415, 81678). |