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Habitat: known mainly from the main channels of large whitewater rivers such as the Rio Solimões (Amazon) and Rio Ucayali. In the Tefé region, encountered only during the rising water period in January and February, and was captured in waters of 2–4 m depth on beaches of alluvial silt and fine sand.
Water quality: The Rio Solimões near Tefé is characterized by high conductivity (90–150 µS/cm), very high turbidity (Secchi disk readings of 0.1–0.4 m, but usually less than 0.15 m), near neutral pH (6.9–7.3), and is well oxygenated from the surface to the bottom (1.6–3.9 mg/l, usually more than 3 mg/l). The temperature of large whitewater rivers is remarkably constant throughout the year (27–32°C), with no stratification. Water chemistry readings at the capture locality of two specimens from the lower Rio Ucayali fell within the above ranges.
Reproduction: All four specimens captured in the Tefé region had maturing, but not fully mature, gonads.
This suggests spawning during the rising water period, which is typical of riverine apteronotids (Crampton, 1998).
Food items: Stomach content analysis was based on four specimens from the Tefé region reveal that the species feeds exclusively on small, autochthonous, benthic insect larvae.
Diet: Micro-caddis fly larvae (Trichoptera: Hydroptilidae) constituted 80–100%(mean87.5, SD9.6,n=4), biting midge larvae (Diptera: Ceratopogonidae) constituted 0–20% (mean7.5, SD9.6, n=4), and beetle larvae (Coleoptera of unidentifiable families) constituted 0–20% (mean5, SD10, n=4) of proportional contents. Most specimens had loose sand grains in the stomach (larger than the grains of sand in the caddis fly jackets), suggesting foraging on sandy substrates.
Parasite: One stomach contained many endoparasitic nematodes (Ref. 83661). |
