First phylogenetic insights into the genus Elmomorphus Sharp, 1888 and discovery of five new species (Coleoptera, Dryopidae)

Genus Elmomorphus Sharp, 1888 is distributed across East and Southeast Asia representing one of the most species-rich lineages of Asian Dryopidae. Here, five new species from Vietnam are described ( E. bachma sp. nov ., E. calvoides sp. nov ., E. cucphuong sp. nov ., E. parastriatellus sp. nov ., and E. vestitus sp. nov .) and E. sarawakensis Chûjô & Satô, 1964 is redescribed, based on the specimens from Sarawak (Malaysia). DNA sequences were generated for four loci (COI, 28S rDNA, ITS2, and CAD) for 15 species collected in Vietnam, two Japanese species ( E. brevicornis Sharp, 1888 and E. amamiensis Nomura, 1959), and the Malaysian E. sarawakensis . Phylogenetic relationships were inferred using maximum likelihood and Bayesian inference on concatenated datasets and compared with species-tree estimates obtained under the multispecies coalescent framework. To assess gene-tree discordance, phylogenetic networks using PhyloNet and NANUQ were reconstructed. Our analyses provide new molecular insights into the phylogeny of Elmomorphus , revealing that majority of the species form distinct lineages, but several clades appear to be affected by incomplete lineage sorting and exhibit conflicting phylogenetic signal across loci. The new molecular data clarify relationships within the analysed species and provide a foundation for future phylogenetic and biogeographic studies of Oriental Dryopidae.