Leporinus amazonicus, a new anostomid species from the Amazon lowlands, Brazil (Osteichthyes: Characiformes)

Abstract

Leporinus amazonicus, a new species of anostomid fish, is described from the central portion of the Amazon lowlands. It is a medium-sized fish (up to 250 mm SL) with streamlined body (maximum body height approximately 25% of SL) and high lateral line scale counts (45–47). Leporinus amazonicus is morphologically similar to the slender bodied species L. cylindriformis Borodin, 1929 and L. brunneus Myers, 1950, but differs from them by the higher lateral line scale count (41–43 in L. cylindriformis and 36–42 in L. brunneus) and by a different color pattern. Moreover, L. amazonicus is apparently restricted to the white waters of the Amazon lowlands whereas L. cylindriformis and L. brunneus are known only from clear and black waters of several of the Rio Amazonas tributaries. Despite intensive collecting efforts historically developed in Brazilian Central Amazon, just a few specimens of L. amazonicus were caught, indicating that the new species is relatively rare in that area and apparently do not join in large schools. However, this supposed rarity may be biased by the concentration of our collecting efforts around Manaus, which may represent a marginal distribution of this species. Nevertheless, the presence of a new species of a taxonomically well-known fish family in an area intensively exploited by commercial and subsistence fisheries evidences the need for fish species surveys in the Amazon, even in supposedly well sampled sites and around the most populous areas.