Euura vittata (Serville, 1823)

Prous, Marko, Liston, Andrew, Monckton, Spencer K., Kramp, Katja, Vårdal, Hege, Vikberg, Veli, Heibo, Erik & Mutanen, Marko, 2025, West Palaearctic species of Euura Newman, 1837 (Hymenoptera, Tenthredinidae), European Journal of Taxonomy 977, pp. 1-377 : 186

260 Euura vittata group

Genetic data divides the group into two clades, based both on mitochondrial COI and nuclear genes. This is supported by the structure of the male penis valves. For females, no reliable characters have been found to separate the subgroups. The ventral part of the abdomen tends to be green in live E. vittata but yellowish to black in the tillbergi subgroup and brown or yellowish in E. hedstroemi ( E. vittata subgroup). Colouration of the abdomen in living specimens requires confirmation for E. hulteni and E. minivittata Prous & Mutanen sp. nov. (both in the E. vittata subgroup). Euura vittata (some specimens from the Pyrenees, e.g., DEI-GISHym11811) can also be nearly completely pale (unknown whether green or yellow in life). Because of the lancet (and usually characteristic colouration of the abdomen), E. krausi ( E. tillbergi subgroup) females can be separated reliably from the other species in the vittata group. The lancet of E. krausi has flat serrulae, while all the other species in the group have (near) papilliform serrulae. The size and shape of the serrulae of the non- krausi species varies, but there does not seem to be a clear correlation with other morphological characters or genetics, which prevents the use of the serrulae structure for species identification. Unfortunately, there are no other clear morphological characters to diagnose the species other than E. krausi , but the evidence from nuclear genes suggests the presence of five or more additional species (four in the vittata subgroup, one in the tillbergi subgroup). We have recognized five species in addition to E. krausi as the other 3–4 apparent nuclear lineages are currently better treated as part of E. vittata (see justification under the species). The clusters suggested by nuclear genes do show tendencies in colouration and size, which seems to enable identification of most of the females. Differences between the males are less clear and currently we have not been able to separate them morphologically. Additional morphological (ideally including larvae) and genetic examination is needed to resolve species boundaries in the vittata group.