tered on rays and spine, spots fading posteriorly and distally. Anal fin spotted randomly
with spots centered over membranes. Ventral surface behind mouth much lighter than
sides, occasionally with slight mottling. Upper lip with small dark spots. Barbels mottled.
Eye with dark spots dorsally, mottled ventrally.
Considerable ontogenetic change observed in coloration (Figs. 3 & 4). The smallest
individual examined with mottled head and spots that appear to form dorsal saddles posteriorly;
large spots present on all fins. Slightly larger individuals with spots on the head, but
posterior body spots still forming saddles; dorsal and caudal fins with bands. As individuals
grow, the spots become more numerous and the relative size of the spots decreases.
Ecology: Uncommon. Found in medium to large rivers among boulders. Usually in
runs and riffles, but small individuals may be found hidden in the holes of lateritic rocks in
pools. Most specimens I collected were collected at night. The largest individual was captured
in a gill net in the main stem Essequibo and it appeared to be moving from deeper
water into the shallows where there were exposed boulders.