Rhogogaster magniserrula Viitasaari, 2015, holotype
Rhogogaster magniserrula Viitasaari. Holotype ♀
Finland: “Suomi PP: Simo 12.6.1948, O. Peltonen” (ca. 65.670°N, 25.052°E), coll. SDEI.
Paratypes: Finland: 1 ♀ Sipoo, Nevas, 6687:3412, margin of deciduous forest, (ca. 60.285°N, 25.408°E) 14–20.7.1985, A. Albrecht leg., coll. MV; 1 ♀ EnL, Enontekiö, Pallastunturit, Röyninkuru, (Grid2E) 756:337, 26.7.1951, J. Kaisila leg. (ca. 68.074°N, 24.058°E), coll. MV. This specimen was found on snow and the record was published as “R. viridis L.”, identified by T. Kontuniemi [Kaisila 1952: 19]. This paper gives a fairly accurate location between Saivokero and Vuontiskero. Russia: 1 ♀ “Kirov: Kirov: Vyatka 15–23 July 2001. Sweep-net. Leg. Erik Heibo” (ca. 58.462°N, 49.877°E), coll. E. Heibo.
Black color of the upper head forming a ‘ω’: frontal ridges green, frontal field and frons between antennal furrow and inner eye margin largely black, the black parts not fused above the antennal sockets,
Morphology very similar to R. viridis. Body size 10.0 (specimens from Finland) to 12.0 mm (specimen from Kirov). Frontal field with deep frontal groove and antennal furrows deep, thus frontal ridges well defined, antennal crests somewhat bent up. Upper head polished, microsculpture only weakly indicated. Mesoscutellum slightly convex, appendage densely sculptured and medially carinate, both without distinct pits. Saw with 19–21 large serrulae, distances between the elavated
parts (praecalcar) are mostly shorter than the lower parts (postcalcar) of the serrulae. Plantar lobes medium sized, distance between 1st and 2nd (in ♀) about 1.0–1.2 × as long as its own length. Color similar to R. viridis, but black pattern of the head different.
The species belongs in the group of R. viridis (viridis, polaris, sibirica, californica s.l.). The angle of the incision behind the postcalcar (cypsella) is less than 45°, as usual in the group. Furthermore, the densely sculptured appendage of the mesoscutellum and the shape of the frontal field agree with the usual character states in this group. The most distinctive external character of the species is the pale coloration of the head. The frontal ridges are not black in the lower part as in viridis and polaris, but green, in the holotype with an indistinct small dark pit in the lower part. A similar ‘ω’-like black marking is to be found in European Rhogogaster only in R. punctulata, but in this species the postocellar area is almost completely green, and the abdomen is much paler. Exceptionally (1♂ 1♀ of 340 examined specimens), very pale specimens of R. chlorosoma with similar head coloration occur. This form is dorsally much paler than magniserrula, the occiput is nearly completely pale, and the genitalia are different.
The species is the most rarely collected European Rhogogaster. We cannot exclude, that undiscovered specimens of the species are mixed in larger collections under “viridis” in a broader sense. The coloration of the head should make it rather easy to recognize them.
Photos were taken at the SDEI with a Leica DFC 495 digital camera and M205 C microscope. Composite images with an extended depth of field were created from stacks of images using the software CombineZP, and finally arranged and partly enhanced with Ulead PhotoImpact X3.
