Abstract
Mesomexovis Gonzalez-Santillan & Prendini, 2013 is a scorpion genus of the Vaejovidae family that comprises seven species, all endemic to Mexico. The present study describes a new species from Estación de Biología Chamela, Jalisco, related to M.occidentalis (Hoffmann, 1931), M.atenango (Francke & Gonzalez-Santillan, 2006), and M.subcristatus (Pocock, 1898). Mesomexoviscaxcan sp. nov. differs from these species in several respects. Firstly, the carinae of the pedipalp chelae are vestigial. Secondly, the ventral lateral carinae of metasomal segments I-IV are granular, and the ventral submedian carinae of segments I-IV are costate to granular. A microstructural separation between the subex and the basal carina of the capsular area of the hemispermatophore is described for the first time. Mesomexoviscaxcan sp. nov. represents the eighth species of the genus and the fifth reported in the Estación de Biología Chamela. The other scorpions identified in this location are Centruroideschamela Ponce-Saavedra & Francke, 2011, C.elegans (Thorell, 1876) (Buthidae), Konetontlichamelaensis (Williams, 1986), and Thorelliusintrepidus (Thorell, 1876) (Vaejovidae).