• Finally, the non-overlapping geographic distribu- tions of R. cylindraceus and Rivulus sp, the separate phylogeograph- ic history of R. cylindraceus (see below), morphological features found in Rivulus sp. that are not found in R. cylindraceus, such as the dark stripe in both sexes, also found in juveniles, and the pale orange colouration on the ventral part of the body, all indicate that Rivulus sp. should be considered a new species and that R. cylind- raceus and Rivulus sp. have a relatively long history of allopatric divergence.