Ancistrus abilhoai Bifi, Pavanelli & Zawadzki 2009

This species differs from its congeners inhabiting the Río de La Plata and coastalbasins of southern Brazil, except A. agostinhoi, A. multispinis, A. mullerae, A. taunayi and A. formoso, by possessing a maxillary barbel shorter and not free from its lower lip (vs. longer and free from lower lip); from the first 4 species, by the width of mandibulary teeth row 13.4-15.5% of HL (vs. 15.8-19.3%, 15.5-19.4%, 16.5-21.0% and 15.8-23.1%, respectively) and 32.9-37.9% of interorbital width (vs. 38.4-53.6%, 40.7-53.8%, 39.3-58.0% and 39.4-51.4%, respectively); from A. formoso by orbital diameter 11.9-15.3% of HL (vs. 8.3-8.7%), caudal peduncle depth 9.0-10.9% of SL (vs. 7.8-8.7%) and number of dentary teeth 40-68 (vs. 110) (Ref. 83296).

Dorsal spines (total): 1; Dorsal soft rays (total): 7; Analspines: 1; Analsoft rays: 3 - 4