Dolerus aericepsellus Heidemaa & Mutanen, 2022

Liston, Andrew, Mutanen, Marko, Heidemaa, Mikk, Blank, Stephan M., Kiljunen, Niina, Taeger, Andreas, Viitasaari, Matti, Vikberg, Veli, Wutke, Saskia & Prous, Marko, 2022, Taxonomy and nomenclature of some Fennoscandian Sawflies, with descriptions of two new species (Hymenoptera, Symphyta), Deutsche Entomologische Zeitschrift 69 (2), pp. 151-218 : 151

Dolerus aericepsellus Heidemaa & Mutanen sp. nov.

Figs 8 , 9

Description.

Holotype ♀. Figs 8A, B , 9B, C .

Colour. Fig. 8A, B . Body black with terga 2-7 and sterna 2-7 orange. Terga 8-9 brownish black, 10 brownish basally but yellowish brown apically, apical third of protibiae brownish. Ventral margin of valvula 3 and cerci brownish. Wings clear.

Measurements (mm). Body length: 5.0, distance from tegula to base of pterostigma: 3.1, head breadths: 1.46 (max. at eyes), 1.28 (max. behind eyes), 1.07 (min. behind eyes), head length (behind eyes): 0.21, max diameter of eye: 0.62, breadth of postocellar field: 0.36, OC: 0.96, OOCL: 0.35, OOL: 0.20, POL: 0.19. Length of: metafemur: 1.18, metatibia: 1.76, ovipositor sheath (from the base of valvifer 2 to the apex of valvula 3): 1.01. Length of flagellomeres: 1: 0.48, 2: 0.41, 3: 0.37, 4: 0.31, 5: 0.29, 6: 0.26, 7: 0.25.

Large structures. Clypeal emargination almost half as deep as clypeal median length. Clypeus asymmetrical, its antero-lateral lobes round at apex, the left lobe longer than the right. Distance between antennal sockets 1.6 × as long as the malar space. Length of antennomere 3 about 1.24 × that of 4. Oblique furrow not outlined. Distance between cenchri about 1.1 × as long as width of cenchrus. Metatarsomere 1 about 1.75 × as long as 2. Mesoscutellar appendage with weakly outlined ridge medially.

Setae. Metascutellum with few setae (about 5). Abdomen dorsally mostly pubescent from segment 7 to last one (laterally and ventrally from 2 to last one). Longest setae of valvula 3 in dorsal view markedly curved in apical third, and forming an angle of about 80-90° (Fig. 9B ).

Macrosculpture. Pits on head rather irregular in size and distribution, more distinct and separated on postocular and postocellar area. Density and size of pits on thorax vary, the largest (partly fused) on lateral sides of median mesoscutal lobes and on mesoscutellum. Pits on lateral lobes of mesoscutellum and near the median mesoscutal groove sparse and small. Pits on mesepisternum largest, partly isolated and round, partly polygonal and fused (Fig. 9C ). Distinct pits on pectus nearly absent (Fig. 9C ).

Microsculpture. Meshes on mesoscutellar appendage extensive, on tergum 1 absent, on metepimeron (Fig. 9C ) and on ventral surface of metacoxa absent. Sculpticells on anterior half of katepimeron of mesopleuron rib-like, irregular and of uneven height, and absent on metepimeron, pectus, and terga (all glossy).

Male. Figs 8C, D , 9A, D-G . Closely resembles the female, but the anterior margin of tergum 2 blackish, basal 2/3 of hind tibia (with apical spurs), and base of metatarsomere 1 reddish yellow (Fig. 8C, D ). Penis valve valviceps long and narrow (Fig. 9G ).

Measurements (mm). Body length (paratype male ZMUO.035740): 5.3, distance from tegula to base of pterostigma: 3.2, max. diameter of eye: 0.60, head breadth: 1.47 (max. at eyes), breath of postocellar field: 0.38, head length (behind eyes): 0.24, OC: 1.01, OOCL: 0.18, OOL: 0.29, POL: 0.21, metafemur: 1.25, metatibia: 1.64, metatarsus: 0.50. Length of flagellomeres: 1: 0.59, 2: 0.51, 3: 0.50, 4: 0.44, 5: 0.41, 6: 0.39, 7: 0.41.

Genetic data.

Three specimens with DNA barcode sequence data are available. They comprise a distinct cluster BIN BOLD:ABV8002, with 0.3% intraspecific variability. Based on sequences longer than 600 bp, the minimum distance to the closest relative D. aericeps (n=26) is 3.9%, but a few specimens identified as D. yukonensis from North America show a minimum distance of even less, 3.6%.

Differential diagnosis.

Adults of D. aericepsellus are most similar to D. aericeps Thomson, but are distinguished by the following characters: smaller body size (similar to D. elderi Kincaid, 1900, or smaller); very short, strongly narrowing postocular area; glossy metascutellum with few distinct pits and setae (3-6); pectus without distinct pits; and thorax black, including tegulae (based on the barcoded specimens: 1♀ 2♂). Lateral postocellar furrows very distinct in both sexes (Fig. 9F ), like in D. aericeps and D. incisus . The thorax of female D. aericeps is usually largely red, whereas in the D. aericepsellus paratype female it is almost entirely black. Dolerus aericeps ab. nigricollis was described by Lindqvist (1943) from northern Finland close to the localities where D. aericepsellus was collected. We examined the type specimen of Dolerus aericeps ab. nigricollis deposited in the MZH and found that it is not conspecific with D. aericepsellus but with D. aericeps , although it has a nearly completely black thorax, with two obscure reddish flecks. Some other examined specimens of D. aericeps from northern Finland show reduced red markings on the thorax, suggesting that this character varies in D. aericeps .

Type material.

Holotype ♀. Type locality: Finland, Enontekiö, Pousu. Labelled [white, printed if not given otherwise]: "FIN Le Enontekiö Pousu 7651:3266 [68.846°N, 21.197°E] 27.6.2020 Marko Mutanen leg.", "Sawfly tissue 2020-1079 M.Mutanen" [greenish], “http://id.zmuo.oulu/fi/ZMUO.044566”, "Holotypus [block letters] ♀ Dolerus aericepsellus Heidemaa & Mutanen, 2022 [handwritten in block letters] des. M. Heidemaa" [red]. Good condition: wings spread, left fore and mid legs removed as tissue samples. ZMUO.

Paratypes. Total: 1 ♀, 3 ♂: Finland: Lapponia inarensis, Utsjoki Pulmankijärvi, YKJ grid coordinates: 7761:3539 [69.928°N, 28.031°E], 1♂ (ZMUO.033245) 07.07.2017, leg. M. Mutanen, N. Mutanen, A. Mutanen, SDEI. 1♂ (ZMUO.035740) (Fig. 9A, D-G ), same collection data as preceding, but 05.07.2018, ZMUO. Lapin Lääni, Nuorgam 17 km SSE, 69.944°N, 28.041°E, 1♀ (BC ZSM HYM 11450), leg. M. Kraus, ZSM. 1♂ (BC ZSM HYM 11451), same collection data as preceding, ZSM.

Etymology.

The name is an adjective derived from the species name of its closely similar sister species, D. aericeps Thomson, using the Latin diminutive suffix - ellus.

Figures

Figure 8. Dolerus aericepsellus sp. nov. A, B. Holotype ♀ (ZMUO. 044566); A. Dorsal habitus; B. Lateral habitus and labels (below); C, D. Paratype ♂ (ZMUO. 035740); C. Dorsal habitus; D. Lateral habitus.

Figure 9. Dolerus aericepsellus sp. nov. A. Head frontal, paratype ♂ (ZMUO. 035740); B. Sawsheath dorsal, holotype ♀; C. Thorax lateral, holotype ♀, metepimeron (arrow); D-G. Paratype ♂ (ZMUO. 035740); D. Thorax dorsal; E. Thorax lateral; F. Head dorsal; G. Penis valve.