Synopsis of the genera and species of the tribe Clivinini (Coleoptera: Carabidae) of the Chaco province and systematic review of the Neotropical genus Pyramoides bousquet, 2002 (Scaritinae: Clivinini)

Abstract

The Chaco is one of the most extensive biogeographic provinces in South America, encompassing parts of Argentina, Paraguay, Bolivia, and southern Brazil. It is characterized by deciduous and semi-deciduous forests, xerophytic vegetation, and savannas with seasonal flooding, which face serious threats due to anthropogenic intervention, leading to biodiversity loss and habitat degradation. Knowledge about the carabids of the tribe Clivinini in this region is limited and lacks comprehensive studies for fauna characterization. Recognizing its importance, this dissertation is presented in two chapters, each focusing on fundamental aspects of the systematics of Clivinini (Coleoptera: Carabidae) in the Neotropical region. The first chapter, entitled “Synopsis of the Genera and species of Clivinini (Coleoptera: Carabidae) of the Chaco Biogeographic Province,” aimed to develop a synopsis of the genera and species of this tribe for the Chaco biogeographic province. In this work, 57 species were documented, distributed among 12 genera and three subtribes. The most representative genera were Semiclivina Kult, 1947, with 12 species; Clivina Latreille, 1802, with nine species; Schizogenius Putzeys, 1846, with eight species; Semiardistomis Kult, 1950; and Aspidoglossa Putzeys, 1846, with six species each. Sixteen new species records were identified: 14 for Argentina, one for Brazil, and the first record of the genus Nyctosyles Putzeys, 1867 for Bolivia. This study also significantly expanded the knowledge of the distribution of several species in the Chaco biogeographic province, highlighting the relevance of this region as a biogeographic refuge and the need for future research to fill knowledge gaps on Neotropical Clivinini. The second chapter, entitled “Systematic Revision of the Neotropical Genus Pyramoides Bousquet, 2002 (Scaritinae: Clivinini),” focused on a comprehensive systematic revision of this genus, recognizing 11 species. The genus Pyramoides and its type species, Pyramoides crassicornis (Putzeys, 1845) and Pyramoides oblongicollis (Putzeys, 1861), were redescribed. In addition, nine new species were described: Pyramoides lispectorae sp. nov., Pyramoides matogrossensis sp. nov., Pyramoides amazonensis sp. nov., Pyramoides colombiaensis sp. nov., Pyramoides martinae sp. nov., Pyramoides garciae sp. nov., Pyramoides merianae sp. nov., Pyramoides paraensis sp. nov., and Pyramoides pantanensis sp. nov. These new species were determined based on the analysis of external morphological characters and the male and female genitalia. Identification keys, geographic distribution maps, and photographs of the studied species were also developed. The monophyly of the genus Pyramoides was confirmed through a phylogenetic analysis based on a matrix of 82 external morphological characters of adults, which included 16 species (one outgroup and 15 ingroup species). The selected outgroup was Scarites paraguayensis Bänninger, 1928, while the ingroup included representative species of the subtribes Clivinina and Forcipatorina. The analyses, performed under both equal and implied weighting, generated trees that corroborated the monophyly of the genus. This revision not only expands the taxonomic and biogeographic knowledge of Pyramoides but also highlights its importance as a model for studying evolutionary processes within Clivinini. In addition, it establishes a solid foundation for future research, promoting the understanding and conservation of biodiversity in one of the richest and least explored regions of the world.