| Remarks |
Abstract: Rivulus foliiscola, n. spec. is described from specimens collected at a single locality at the outermost southern tip of the department Guainía, Colombia, where the Rio Negro flows into Brazil, and Brazil's borders, Venezuela and Colombia meet. This locality was only about 2 km distant from one at which two other undescribed species were collected sympatrically in a shallow forest creek. Rivulus foliiscola n. spec. lives in deep pits with standing water, a habitat type supposedly more suitable for annual fishes. The new species displayed unusual behaviors, e.g., it apparently preferred to live near, and spawn upon, the substrate. Rivulus foliiscola is also divergent in coloration and fin shape from other Rivulus species and evinces a characteristic "snake-like" behavior upon capture as if seeking cover. Initially, these traits lead the authors to suspect they had collected a new annual species. However, its lifespan in captivity for more than two years, the relatively short incubation period of its embryos, and the absence of embryonic diapause strongly suggest that it is a non-annual, and thus more appropriately referred to the genus Rivulus, family Rivulidae. |