No abstract

To elucidate the species of the genus Ancistrus that inhabit freshwater systems of Ecuador, cataloged lots of the Fish Collection, Museo de la Escuela Politécnica Nacional (MEPN), in Quito, were analyzed. Four species were identified: Ancistrus alga (Cope, 1872), A. malacops (Cope, 1872), A. clementinae Rendahl, 1937, and a new species that herein is described. Ancistrus clementinae inhabits aquatic systems of the Pacific slope, mostly in the Guayas River drainage. The other three species live in freshwater systems that drain to the Amazon River Basin. Ancistrus alga inhabit the northern and central portions of eastern Ecuador. Ancistrus malacops has a broad distribution from north to south, but is absent from the Santiago River. Both species occasionally live in sympatry. The new species is restricted to the Santiago River, in Morona-Santiago province. Each species has unique external morphological features and/or a coloration pattern that allow unambiguous identification, at least of males. This paper provides a description of the new species, and a re-description and images of the other three.

No abstract

At the Fish Collection of the Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Quito, three species traditionally grouped in the genus Hemiancistrus were identified: H. annectens (Regan 1904), H. landoni Eigenmann 1916, and a new specie described here. The new species inhabits exclusively in the Esmeraldas River Basin, Pacific slope, northwestern Ecuador. It is easily recognized by the completely naked abdomen, with rounded, dark spots, and a different color pattern on the dorsal and caudal fins. A comparative analysis of bones related to the opercular mobility, shows important differences between H. annectens, H. landoni, and the new species, suggesting that H. annectens does not belong to the genus Hemiancistrus or the Ancistrini group. According to the characteristics observed in these bones, H. annectens shows greater similarity to those reported in species of the Hypostomini group, supporting its inclusion in this group, but placing it in the genus Hypostomus requires further analysis. On the other hand, the conditions observed on the bones of Hemiancistrus landoni and the new species suggest that both are inside of the Ancistrini group. The new species is placed in the genus Hemiancistrus tentatively, pending future analysis.