Map of the study area in the Northern and Central Main Ethiopian Rift (NMER, CMER) showing sampling sites and examined material; thick lines denoting Main Rift faults, dashed lines showing transversal faults (Bonini et al. 2005). Study sites: S1–S6 and T1–T8 Awash River drainage, G1 Gotta River (type locality of G. rothschildi), M1 Meki River (type locality of G. makiensis), Z1–Z2 Lake Ziway, and L1 Lake Langano. Sampling sites in red showing localities where G. makiensis is known from examined material or was recorded during recent surveys. The small inserted map showing known distribution range of G. makiensis in the Awash and Meki River drainages.