biostudies-literatureUnknown16(10)Vujic ATwo new species groups within the avidus-nigritarsis lineage of the hoverfly genus Merodon Meigen are here defined and assessed, i.e., the Merodon caudatus and Merodon ottomanus groups. Within the M. caudatus group, two species are recognised:Merodon caudatus Sack and a new species, Merodon crispotarsus sp. nov. Within the M. ottomanus group, an extensive examination of material from different collections revealed the presence of four new species, Merodon auriolus sp. nov., Merodon paeninsula sp. nov., Merodon projectus sp. nov., and Merodon rostrum sp. nov., apart from Merodon ottomanus Hurkmans. The genetic characterisation of species from the M. ottomanus group was performed through MaximumInsects1009https://www.ebi.ac.uk/biostudies/studies/S-EPMC12563486biostudies-literatureDeja Vu in Merodon Taxonomy (Diptera: Syrphidae): Unveiling Hidden Species Inside Merodon caudatus and M. ottomanus Taxa.PMC12563486Acanski JAndric AVujic AKocis Tubic NRadenkovic SPerez-Banon CDjan MRicarte ARojo STot TLikov LfalseDeja Vu in Merodon Taxonomy (Diptera: Syrphidae): Unveiling Hidden Species Inside Merodon caudatus and M. ottomanus Taxa.Two new species groups within the avidus-nigritarsis lineage of the hoverfly genus Merodon Meigen are here defined and assessed, i.e., the Merodon caudatus and Merodon ottomanus groups. Within the M. caudatus group, two species are recognised:Merodon caudatus Sack and a new species, Merodon crispotarsus sp. nov. Within the M. ottomanus group, an extensive examination of material from different collections revealed the presence of four new species, Merodon auriolus sp. nov., Merodon paeninsula sp. nov., Merodon projectus sp. nov., and Merodon rostrum sp. nov., apart from Merodon ottomanus Hurkmans. The genetic characterisation of species from the M. ottomanus group was performed through Maximum2025-01-01T00:00:00Z2025 Sep2026-05-14T03:22:15.332Z2026-05-14T03:12:52.651ZS-EPMC125634864114887810.3390/insects16101009