Euura ursaminor, Liston & Vikberg & Mutanen & Nyman & Prous, 2023

Liston, Andrew, Vikberg, Veli, Mutanen, Marko, Nyman, Tommi & Prous, Marko, 2023, Palaearctic willow-catkin sawflies: a revision of the amentorum species group of Euura (Hymenoptera, Tenthredinidae), Zootaxa 5323 (3), pp. 349-395 : 382-383

Euura ursaminor new species

Figures 13 , 15A–B

Diagnosis. Resembles some specimens of E. microphyes in its small body size. Euura microphyes differs in its distally narrower valvulae 3 (0.9–1.0 × as wide as narrowest apical width of metatibia) and higher lancet.

Description. Female ( Fig. 13A–B ). Body length 2.75–3.00 mm [holotype 2.75 mm]. Black. More or less pale are: labrum and mandibles, upper inner orbits, tibiae, and apices of femora. Wing veins basad of forewing pterostigma brown, distally paler; pterostigma and costa pale.

Head. In dorsal view strongly narrowed behind eyes; length posterior of eye about 0.4 × length of eye ( Fig. 13D ). Dull, with coriaceous sculpture on all parts except labrum ( Fig. 13C–D ). Mostly densely setose; less so on ocellar and frontal areas; setae on temples and upper inner orbits about as long as anterior ocellus but much shorter on ocellar and frontal areas; setae pale. Clypeus slightly emarginate medially; labrum apically rounded ( Fig. 13C ). Antenna ( Fig. 13F ) 1.00–1.05 × as long as fore wing costa.

Thorax. Pronotum dull, with fine, reticulate sculpture. Tegula densely and finely punctured; interspaces shiny. Medial mesoscutal lobe dull, with strong sculpture; laterally with deep punctures. Lateral mesoscutal lobes and mesoscutellum shinier, with sparser punctation and less sculptured interspaces.Lateral mesoscutal lobe approximately 1.60–1.70 × as long as greatest width. Anterior of thorax more densely setose than posterior; setae about 0.3–0.5 × as long as anterior ocellus, adpressed. Mesoscutellum as broad as long, with no indication of a longitudinal median furrow. Mesepisternum unsculptured, shiny; dorsally with dense setae, about 0.3 × as long as diameter of anterior ocellus; ventrally largely glabrous.

Abdomen. Valvulae 3 in lateral view ( Fig. 13H ) clearly orientated upwards; rather narrow, with rounded apex. In dorsal view ( Fig. 13G ) strongly expanding distally; apical width about 1.6 × narrowest distal width of metatibia. Cercus reaches back past tip of valvula 3. Lancet ( Fig. 15A–B ): slightly curved; 14–20 annular sutures; all serrulae with clearly developed lobe; basal annular sutures without ctenidial teeth. Base of tangium without clearly developed lobe.

Male. Unknown.

Etymology. Ursa Minor is the constellation in the northern sky which contains Polaris, the pole star, which is also the name of the Salix species from which the holotype was reared. The species name is to be treated as a noun.

Biology. Host plants: Salix polaris and S. reticulata .

Distribution. Northern Finland.

Figures

FIGURE 13. Euura ursaminor n. sp. A–B, D, G–H) ♀ paratype DEI-GISHym31946. C, E–F) ♀ holotype PR.513VV. Scale bars 1 mm.

FIGURE 15.Lancets.A–BEuura ursaminorn. sp.:A) holotypePR.513VV.B) paratype PR.514VV, anomaliesin annularsutures and serrulae arrowed. C–E Euura microphyes: C) PR.498VV. D) Amauronematus pyrenaeus paratype DEI-GISHym12667. E) PR.512VV, anomalies in annular sutures arrowed.