Hypancistrus margaritatus differs from all other species of Hypancistrus by its color pattern consisting of dense, small, light-colored spots on a dark base color (vs. color pattern of light spots on a dark base color in H. inspec¬tor, H. lunaorum, and H. contradens). This species has consistently-sized spots on head and trunk about the size of the nasal aperture (vs. smaller spots on head than trunk in H. inspector, spots usually smaller than half the nasal diameter in H. lunaorum, and spots ranging in size from equal to or larger in diameter of nasal aper¬ture in H. contradens); has more spots, 23 in a lateral, horizontal series from snout tip to base of caudal peduncle 23 in holotype (vs. 8-20 spots in H. contradens; 8-16 in H. lunaorum); and has more densely-packed spots relative to H. lunaorum, with spots on lateral surface of the body having a minimum interspot to spot diameter ratio ranging from 1.0-1.6 (vs. 1.9-4.4 in H. lunaorum) (Ref. 114591).

Description: Dorsal fin II,7; anal fin i,4; pectoral fin I,6; pelvic fin i,5 (Ref. 114591)