Etsaputu relictum, a new genus and species sister to all other Ancistrini, is described from the upper Maraon River in Northern Peru. Etsaputu relictum can be diagnosed from all other Hypostominae by having a coracoid with a serrated posterior margin of the posterior process, an opercle with a process extending ventrolaterally from the ventral margin, and branchiostegals one and two fused. Etsaputu relictum is further distinguished by having cheek plates evertible to less than 45 from the sagittal plane, by having fewer than ten (typically zero or six) enlarged cheek-plate odontodes, by having enlarged cheek-plate odontodes straight and no longer than 15 times length of odontodes on lateral body plates, by having large eyes (mean 24.0% of head length, range 21.727.6% HL), and by having uniformly gold-brown to bronze base color with golden sheen when alive.
Lujan, N. K., Armbruster, J. W., & Rengifo, B. (2011). A new basal ancistrini genus and species from the andes of Northern Peru (Siluriformes: Loricariidae). Copeia, (4), 497-502. https://doi.org/10.1643/CI-10-201