Eastern Colombian Paramo Liodessus Guignot, 1939 diving beetles are genetically structured, but show signs of hybridization, with description of new species and subspecies (Coleoptera, Dytiscidae)

We studied Liodessus diving beetles from six eastern Colombian Paramo areas, as well as from the Altiplano. We discovered a highly characteristic new species, based on male genital morphology, Liodessus santarosita sp. nov., in the Paramo de Guantiva-Rusia. Specimens from the Altiplano around Bogota, and the Paramos of Almorzadero, Chingaza, Matarredonda, Rabanal y Rio Bogota and Sumapaz form one clade of genetically similar populations based on mitochondrial Cox1 sequence data. The individuals of this clade are sub-structured according to their geographic distribution. The populations differ from each other mainly in terms of body size and coloration and, at most, subtly in their genital morphology. In two cases, we find putative hybrid populations between Altiplano and Paramo areas. We suggest that the different Paramo populations are in an early phase of speciation, and perhaps already genetically isolated in some cases. They are here assigned sub-species status to highlight these ongoing processes pending more comprehensive geographic sampling and use of genomic data. We refer to this clade as the Liodessus bogotensis complex, containing Liodessus b. bogotensis Guignot, 1953; Liodessus b. almorzadero ssp. nov.; Liodessus b. chingaza ssp. nov.; Liodessus b. lacunaviridis Balke et al., 2021, stat. nov.; Liodessus b. matarredonda ssp. nov., and Liodessus b. sumapaz ssp. nov.