Liodessus picinus sp. nov. is described from the Páramo de Sumapaz near Bogota D.C. at 3,500 m above sea level. The species can be distinguished from the other Colombian Liodessus species by its dark coloration, discontinuous habitus, shiny surface of the pronotum and elytron, presence of a distinct occipital line, distinct basal pronotal striae, short or even faint basal elytral striae, as well as by its distinct geographic distribution and cox1 signature.

Colombia, Dytiscidae, Liodessus, new species, Páramo, Sumapaz

Diving beetles of the genus Liodessus Guignot, 1939 belong to the tribe Bidessini and occur in the New World as well as the Afrotropical Region (Biström 1988; Nilsson and Hájek 2021). They are typically smaller than 3 mm and inhabit a variety of mainly lotic habitats. Andean species reach altitudes of nearly 5,000 m, where they are the most abundant aquatic beetles (Balke et al. 2020a, 2020b).

However, diving beetles from the high altitudes of the Puna and Páramo regions remain poorly studied. Since 2019, as the result of a research and training cooperation between our institutions, 10 new species were described from these regions of Peru (Balke et al. 2019, 2020b) and Colombia (Megna et al. 2019; Balke et al. 2021). It became apparent that many more new species of Liodessus remain to be discovered in the vast Andean highland ecosystems, most of them likely endemic to one or a few Páramo or Puna areas, respectively. To address this in a combined evidence pipeline, we suggested a DNA sequence-based platform for the study of these insects (Balke et al. 2020a, 2020b) using the Barcode of Life Data System (BOLD) of the Canadian Centre for DNA Barcoding and the 5′ mitochondrial cox1 gene fragment (http://www.boldsystems.org) (Ratnasingham and Hebert 2007).

It is well understood that one genetic marker alone cannot be the omnipotent tool for taxonomy, in particular markers such as cox1, which are not involved in speciation per se (Kwong et al. 2012). Rather, such DNA sequence data have the purpose of guiding the sorting of specimens to operational units and then flank taxonomic decision-making process. This approach has been utilized successfully to study very diverse beetle taxa (Tänzler et al. 2012; Riedel et al. 2013a, 2013b), including our own previous work on Liodessus. The approach can technically be scaled up massively using next generation sequencing technology, which is already also reducing analytical costs (Wang et al. 2018). This does, however, and that is important to note, not replace taxonomic expertise and the evaluation of morphological structures (Riedel et al. 2013a). Here, we report the discovery of another new species of Liodessus from Páramo de Sumapaz (Fig. 3A), the world’s largest Páramo system, near Bogota, Colombia. Interestingly, while we sampled more than 100 specimens of Liodessus bogotensis Guignot, 1953, we only found three females of the new species.

This work was made possible by a grant from the Alexander von Humboldt foundation under the Research Group Linkage Programme, Evolution of the high Andean insect fauna project. We are grateful for the generous support from the SNSB-Innovative scheme, funded by the Bayerisches Staatsministerium für Wissenschaft und Kunst (Project: “Geographische Isolation, Endemismus und Artbildungsprozesse bei Insekten in der hochmontanen Páramo Kolumbiens (und darüber hinaus)”). Michael Balke acknowledges support from the EU SYNTHESYS program, projects FR-TAF 6972 and GB-TAF-6776, which supported this research during visits to Natural History Museum in London and Muséum national d’Histoire naturelle in Paris in 2017. We thank the Agencia Nacional de Licencias Ambientales (ANLA) for issuing collecting and export permits. We thank Dr Simon Pflanzelt (Botanischer Garten München-Nymphenburg) for identifying the plant genera depicted in Figure 3C and D.

Consortium of European Taxonomic Facilities (CETAF) data use statement: “Data on genetic material contained in this taxonomic article are published for non-commercial use only. Utilization by third parties for purposes other than non-commercial scientific research may infringe the conditions under which the genetic resources were originally accessed, and should not be undertaken without obtaining consent from the original provider of the genetic material.”