Systematic review of the genus Mesus Chevrolat, 1858 (Carabidae: Scaritinae: Clivinini)

Abstract

This dissertation comprises a Taxonomical revision and cladistic analyses of Neotropical genus Mesus Chevrolat 1858, aimed to undertake a taxonomic and systematic revision of the genus Mesus Chevrolat 1858. After the taxonomic review of the genus, 12 species were recognized. The genus Mesus and the previously described species Mesus rugatifrons Chevrolat 1858, Mesus gigas Reichardt 1974, Mesus mesus Reichardt 1974, Mesus nanus Reichardt 1974, Mesus pseudogigas Vieira & Bello 2004, and Mesus hornburgi Dostal 2016 were redescribed. Six new species were described: Mesus chevrolati sp.nov., Mesus ayri sp.nov., Mesus garciae sp.nov., Mesus casariae sp.nov., Mesus reichardti sp.nov., and Mesus campaneri sp.nov. The new species were identified based on the analysis and description of external morphological characters, male and female genitalia, and linear morphometric measurements. Identification keys, photographs, distribution maps, and illustrations of the species were provided. Finally, the monophyly of the genus Mesus and the phylogenetic relationships among the species were tested. A cladistic analysis of the genus was performed using a matrix consisting of 18 species and 2 characters derived from the external morphology of the adult, as well as the female and male genitalia. To assess monophyly, two species from the subtribe Clivinina (Whiteheadiana minor (Putzeys, 1866), Paraclivina fassati (Kult, 1947), Ancus depressifrons (Putzeys, 1866), Oxydrepanus minimus (Putzeys, 1866), Semiclivina (uroclivina) berguri (Dostal, 2011), Pyramoides oblongicollis (Putzeys, 1861)) were selected as an internal group, and one species from the subtribe Forcipatorina (Ardistomis ferrerai (Balkenohl, Pellegrini & Zampaulo, 2018)) served as the external group. The analysis yielded two hypotheses: one with equal weighting and the other with implicit weighting, both confirming the monophyly of Mesus. Until now, limited information was available on the two studied genera, and the phylogenetic relationships of Neotropical genera remain a topic of debate among experts. Therefore, this dissertation contributes to the knowledge of biodiversity and the evolutionary history of the carabid fauna in the Neotropical region.