INTEGRATIVE TAXONOMY OF CAVE CRICKETS OF THE GENUS ENDECOUS SAUSSURE, 1878 IN THE CAATINGA BASED ON MOLECULAR, ACOUSTIC AND MORPHOLOGICAL EVIDENCE
Subterranean Biology; Vicariance; Molecular evolution; Cryptic species; Cave crickets.
Cave crickets of the Phalangopsidae family are poorly studied and have a low dispersal capacity and wide distribution, which makes them curious for phylogenetic and phylogeographic investigations. Within this family is the genus Endecous, which has been subdivided into three subgenera based on morphological characters and has most of its type localities in caves. Currently, all taxonomic research involving the genus uses morphological, bioacoustic and cytogenetic characters. Here, we reconstruct the phylogeny and phylogeography based on fragments of the cox1 mitochondrial gene. We used 33 samples from 7 locations. Molecular phylogenies were reconstructed using Bayesian Inference and Maximum Likelihood and four approaches (ABGD, PTP, mGMYC, BPP) were used for lineage delimitation. Additionally, some specimens were selected for extraction of the phallic complex and analysis of morphological characters based on the description article. Bayesian analysis suggested two opposing clades along the banks of the Apodi-Mossoró River. This was supported by three delimitation analyses, except for the PTP that followed the division made by Maximum Likelihood into three clades. The divergence time estimate suggests that this speciation occurred at 3.19 Ma (95% HPD) in the Pliocene. The initial divergence between the species was probably correlated with a mechanism of vicariance after the emergence of the channel that would give rise to the river in the period between the Miocene and Quaternary. Possibly, with the decrease in humidity, these species dispersed to caves with recent divergence times between groups. Morphologically, there is a morphological stasis as a result of a stabilizing selection due to Niche Conservatism.