Apistoloricaria Isbruecker & Nijssen, 1986ZBK.
Type species: Apistoloricaria condei Isbruecker & Nijssen, 1986ZBK.
Holotype: FMNH 94683, Ecuador,
Rio Napo drainage, mouth of Rio Tiputini
Representatives of this genus are distributed in the upper Amazon and Orinoco drainages, along the Atlantic slope of the Andes. They inhabit sand substrates and are morphologically adapted to this habitat. As with other representatives of the PseudohemiodonZBK group, their body is strongly depressed and the pelvic fins are used for locomotion, enabling these fish to appear to “walk” on the substrate. Sexual dimorphism is apparent through differentiated lip structure. The lip surfaces of the male are rather papillose while those of the female are filamentous(Nijssen & Isbrücker 1988). These taxa are abdomino-lip brooders. Eggs are laid in a single layered mass, and are attached to the surface of the lower lip and abdomen of the male. Isbrücker & Nijssen (1986a) described the biotope of A. condeiZBK according to D. J. Stewart’s field notes. This species was collected in turbid and dark waters, in moderately fast flowing streams, between 2 to 10 meters deep. No submerged vegetation was noted, and the bottom was made of sand, mud, dead leaves, twigs, branches, and trunks. ApistoloricariaZBK is not well diagnosed and upon further examination, may prove to be a synonym of RhadinoloricariaZBK. These two genera are distinguished primarily by the presence or absence of the iris operculum (absent or vestigial in ApistoloricariaZBK versus present in RhadinoloricariaZBK), a more conspicuous rostrum in RhadinoloricariaZBK, and by the number of fringed barbels (14 in ApistoloricariaZBK versus 12 in RhadinoloricariaZBK). Four valid species are recognized (Ferraris 2003) and a key to the species is available in Nijssen & Isbrücker (1988).