Additional new species of Grouvellinus Champion 1923 (Insecta, Coleoptera, Elmidae) discovered by citizen scientists and genetically barcoded in the field applying a new MinION-based workflow. New Grouvellinus of Borneo

The new species Grouvellinus nigerquadratus sp. nov., G. cruxniger sp. nov., G. luciaensis sp. nov., and G. borneensis sp. nov. from Borneo, are described and illustrated in detail. Two additional species of the genus which are still unknown to science are briefly diagnosed. The material was collected during Taxon Expeditions’ field course which involved citizen scientists, students and taxonomists. Specimens were collected at altitudes between 270 m and 750 m above sea level using fine-meshed hand-nets and ‘blacklight’ traps. The morphological species concept presented here is supported by mtDNA sequences which are the first DNA barcodes for the genus. They were obtained in the field by a newly developed rapid and accurate MinION-based workflow. The inter- and intraspecific genetic distances and the problems regarding cryptic species delimitation are discussed.