Taxonomic Updates on the Merodon fulcratus and M. spinitarsis Species Groups, with Notes on M. syriacus (Diptera: Syrphidae)

Within the Palaearctic, the Anatolian and Iberian Peninsulas are established centers of diversity for the genus Merodon Meigen, 1803. However, recent research also highlights the Eastern Mediterranean and the Middle East as important regions. This study reviews two groups of species found across these regions, the M. fulcratus and M. spinitarsis groups, and clarifies the taxonomic status of M. syriacus Paramonov, 1929. The fulcratus species group consists of two valid species: M. dichopticus Stackelberg, 1968, and M. fulcratus (Becker, 1913). In M. fulcratus, high variability in the shape of the male genitalia has been observed; however, genetic analysis revealed no evidence of diversification within this species. The spinitarsis species group comprises M. spinitarsis Paramonov, 1929, and a new species from Israel: Merodon complicatus sp. n. This new species was previously misidentified as M. syriacus; however, based on the type material, M. syriacus proved to be closest to the East African species M. nasicus Bezzi 1915 from the bombiformis group. Furthermore, Bayesian phylogenetic analysis based on concatenated COI and 28S rRNA sequences strongly supports the placement of M. fulcratus within Merodon (Merodon) and M. spinitarsis within M. (Auremerodon). This study resolves the status of several taxa and highlights important faunal links between different biogeographical regions.