Permopsyche issadensis, Bashkuev, Alexei S., 2011

Bashkuev, Alexei S., 2011, The earliest Mesopsychidae and revision of the family Mesopanorpodidae (Mecoptera), ZooKeys 130, pp. 263-279 : 268-270

Permopsyche issadensis sp. n. Figs 246

Etymology.

From the Isady locality.

Holotype.

PIN, no. 3840/336, well-preserved forewing (part and counterpart).

Paratypes.

21 forewings (see Table 1) and 6 hindwings: PIN, no. 3840/725, 1381-1383, 1385, 1389a. Additionally, 8 forewings and 10 hindwings incomplete or poorly preserved, excluded from the type series.

Locality and horizon.

Isady locality, Vologda Province, North European Russia; Poldarsa Formation, uppermost Severodvinian (Lower Wuchiapingian), Upper Permian.

Diagnosis.

Differs from Permopsyche belmontensis by wing shape, with anterior margin straight and posterior apical margin tending to oblique, different crossveins arrangement, and strongly unsclerotized MP stem. Differs from Permopsyche robustus by branch of SC located more basally and A3 simple. Additionally differs from both species by considerably smaller size.

Description.

Forewing. Moderately broad (length/width ratio 2.3-2.9:1); anterior margin nearly straight, slightly convex basally; apex obtuse to rounded. SC long, reaching or almost reaching basal margin of pterostigma; SC branch approximately at middle of RS+MA stem (somewhat variable in paratypes). Pterostigma distinct, widened, with oblique basal margin. R1 simple, gently bending posteriad at pterostigma. RS and MA forks equally short, approximately as long as their stems. Nodal line distinct, arched, running from tip of SC to hind margin at apex of CuA. Thyridium present as unsclerotized section on MP stem spanning from approximately 1/3-1/2 of its length down to fork, accompanied by desclerotized spot at point of branching of RS and MA ( “thyridulum”, the term introduced by A.P. Rasnitsyn in Ren et al. 2009). Connection between CuA and MP variable (Fig. 4; see also Remarks), from joined at one point (X-junction), with CuA base oblique and M5 lost, to forming well-developed cubito-median Y-vein with almost equal arms at obtuse angle, with CuA base transverse and M5 quite long. cua-cup crossvein transverse. Three simple anal veins. Crossveins not n umerous, mainly distinct or slightly weakened, forming rather stable pattern: one long, oblique, sigmoidally curved r1-rs crossvein; four crossveins between RS, MA, and MP branches; mp-cua and cua-cup crossveins of standard position; cup-a1 and a1-a2 located stepwise along with the base of CuA; occasionally, a2-a3 present. Wing membrane darkened in distal wing half, restricted by nodal line, with saturated patch at center of wing.

Hindwing. Both venation scheme and coloration similar to those in forewing, adjusted for general difference between fore- and hindwings typical of Mecoptera . SC short, reaching wing midlength, variably forking apically (Fig. 6). Pterostigma distinct. R1 with inclined branch in pterostigmal area. A1 separating from CuP relatively closely to base.

Measurements (mm).

Forewing length, 4.25-6.35, width, ca. 1.5-2.5; hindwing length, 3.9-5.5, width, 1.5-2.25.

Remarks and discussion.

In Permopsyche issadensis thewing size varies conspicuously. As shown in the size distribution diagram for forewings (Fig. 5; Table 1), the presence of Y-vein and the transverse (rather than oblique) shape of CuA base (hollow squares vs filled squares) both correlate with the increased wing size (irrespectively of the length/width ratio). However, the size distributions of the two morphotypes overlap broadly. The two wing morphotypes may represent sexual dimorphism. Alternatively, they can be attributed to slight differences in flight mechanics depending on the body size. The distinctive and uniform wing color pattern makes it unlikely that the morphotypes represent two closely related species.

The nodal line (the line of wing flexion) in the forewing of the new species is essentially similar to that of both Mesopsyche ( Novokshonov 1997c) and the recent Panorpa (Ennos and Wooton 1989), suggesting a similarity between flight mechanics of Mesopsychidae and Panorpidae .

Hindwings of Permopsyche are almost as abundant at Isady as the forewings. All the hindwings examined, as far as their preservation allows to tell, have the set of characters (including coloration) diagnostic of the forewings of Permopsyche issadensis and can be confidently referred to the same species.