Sympatric populations of sister species of Brachyrhaphis.

The first records of sympatric populations of the poorly studied sister species Brachyrhaphis roseni and Brachyrhaphis terrabensis are presented. Sympatric populations were found in a total of 14 localities in four river drainages throughout the Pacific slopes of western Panama, and they occurred in a wide range of elevations, from 90 to 651 m. These data expand the elevation range of each species, and provide the first case of sympatric sister species within the genus.