A new species and a new synonymy in the Pristiphora depressa species group (Hymenoptera: Tenthredinidae), with a discussion of global diversity patterns in sawflies feeding on maples (

Now comprising nine known species in the West Palaearctic, and several others in eastern Asia, the depressa species group of Pristiphora Latreille is the most speciose group of sawflies feeding on maples ( Acer ). Pristiphora acutivalva sp. n. is described from Spain and southern France. Dinematus krausi Lacourt is treated as a new junior synonym of Pristiphora ifranensis Lacourt. Although this lineage of Pristiphora apparently uses only Acer species as larval hosts, individual species of the depressa group seem not to be strictly monophagous on single maple species or closely related species. In the discussion, noteworthy patterns in the global distribution of maple-feeding sawflies are highlighted. Congruent with the hypothesis of the origin and initial diversification of Acer in eastern Asia is the high diversity at generic level of maple-specialist sawflies in the East Palaearctic and Oriental realms. Other notable aspects are the absence of nearly all maple-feeding sawflies in North America, and the restriction of maple-feeding Heterarthrus Stephens, 1835, species to the West Palaearctic.