Curculionichthys sabaji is distinguished from all congeners by possessing several dark-brown spots distributed on the body (vs. a variety of pigment patterns, but none of which includes dark-brown spots). It also differs from all con¬geners, except C. coxipone and C. paresi by having the cleithrum with an area free of odontodes (vs. cleithrum completely covered with odontodes). Other characters useful to further diagnosed this species from other congengers include the following: some papillae of the lower lip arranged in a medial longitudinal series extending posterior to dentaries through the middle portion of the lower lip (vs. lower lip with all papillae randomly distributed in from C. piracanjuba, C. sagarana, and C. oliveirai); anterior profile of the head pointed (vs. rounded in C. coxipone and C. oliveirai); odontodes forming longitudinally aligned rows on head and trunk (vs. odontodes not forming longitudinally aligned rows on head and trunk in C. piracanjuba); small, inconspicuous odontodes forming rows on the head and trunk (vs. large, conspicuous odontodes forming rows on the head and the trunk in C. insperatus); caudal fin hyaline, with one dark strip extending from caudal peduncle base to the median caudal fin rays, and dark chromatophores irregular distributed almost forming two bands (vs. caudal fin hyaline, with dark blotch limited to caudal peduncle base in C. insperatus and C. sagarana); absence of one unpaired platelet on the dorsal portion of caudal peduncle (vs. one unpaired platelet on the dorsal portion of the caudal peduncle in C. sagarana); 6?9 lateral abdomen plates (vs. 4?5 lateral abdomen plates in C. oliveirai); absence of contrasting dark geometric spots on the anterodorsal region of body (vs. pres¬ence of geometric spots in C. paresi); not having hypertrophied odontodes on the snout tip (vs. hypertrophied odontodes on the snout tip in C. piracanjuba). In addition, Curculionichthys sabaji can be distinguished by having a shorter dorsal fin spine (18.5?22.7% of SL, vs. 25.2?27.0% of SL in C. paresi; 23.2?26.9% of SL in C. insperatus); a shorter pectoral-fin spine (18.9?23.4% of SL, vs. 27.0?30.1% of SL in C. paresi); a deeper caudal peduncle (7.0?10.0% of SL, vs. 10.8?12.5% of SL in C. oliveirai; 10.2?11.3% of SL in C. paresi); a deeper head (40.9?49.1% of HL, vs. 51.6?59.2% of HL in C. oliveirai); a longer head (34.3?38.6% of SL, vs. 27.9?32.2% of SL in C. piracanjuba; 28.8?33.3% of SL in C. luteofrenatus); a shorter snout (45.5?56.9% of HL, vs. 67.7?72.7% of HL in C. piracanjuba; 67.0?75.3% of HL in C. luteofrenatus) and a shorter interorbital width (30.3?35.7% of HL, vs. 36.7?40.9% of HL in C. piracanjuba; 67.0?75.3% of HL in C. luteofrenatus) (Ref. 113800).

Description: Dorsal-fin rays ii,7; anal-fin rays i,4; pectoral-fin rays i,6; pelvic-fin rays i,5 (Ref. 113800).