Phylogeny and Biogeography of the Termite Genus Labiotermes Holmgren, 1912 (Isoptera, Syntermitinae) Suggests Predominant Sympatric Speciation

Abstract

Aims: We aimed to provide a molecular phylogeny of all currently known and described Labiotermes species to clarify taxonomic relationships, including the synonymy of Paracornitermes, in order to reconstruct the historical biogeography of the genus and investigate the role of specific biogeographic domains in its diversification. Location: South America. Taxon: Termite genus Labiotermes (Isoptera: Termitidae). Methods: A dated Bayesian phylogeny was estimated using complete mitogenomes (14,985 bps) from all species. We performed biogeographic analyses using the BioGeoBEARS R package, testing 12 maximum likelihood models (six default models with and without a time-stratified dispersal matrix) across eight defined biogeographic units. Results: The genus Labiotermes originated approximately 21 Mya. Our phylogenetic analysis corroborated the synonymy of Paracornitermes with Labiotermes. The species L. labralis, L. guasu, and L. oreadicus formed a monophyletic group sister to all other Labiotermes. The top four best-fitting models (DIVALIKE+TS, DEC+TS, DEC+TS+j and DIVALIKE+TS+j) showed no significant differences in their estimations. The analysis revealed limited vicariance but multiple sympatric events, particularly within the western Brazilian savanna (Cerrado). Main Conclusions: The Cerrado has been a key center of diversification for Labiotermes, with multiple dispersal events occurring over the last 10 Mya. These findings underscore the dynamic role of the Cerrado in shaping speciation patterns and highlight how Neotropical landscape evolution has profoundly influenced termite biogeography.