Podonomius robustus, Lukashevich, Elena D. & Przhiboro, Andrey A., 2011

Lukashevich, Elena D. & Przhiboro, Andrey A., 2011, New Chironomidae (Diptera) with elongate proboscises from the Late Jurassic of Mongolia, ZooKeys 130, pp. 307-322 : 311

? Podonomius robustus sp. n.

Etymology.

From Latin “robustus” for stout, after the total habitus.

Material examined.

Holotype: Part and counterpart of partly preserved female PIN 4270/2254 ±, SW Mongolia, Shar Teg (443/1); Late Jurassic.

Diagnosis.

The new species is distinguished by its medium size (wing length 3.7 mm), well-developed, strongly elongate proboscis, wing with C produced beyond R4+5 and reaching wing tip, strongly sclerotized abdomen and legs, and one spermatheca situated proximally of other two.

Description.

Female (Fig. 3). Measurements (mm): Total length 4.1; thorax length 1.5, width ca. 1.0; abdomen length 2.9; wing length 3.7. Total length / wing length 1.1. Coloration. Head, thorax, abdomen, legs uniformly dark. Head 700 μm wide, no less than 1100 μm high with proboscis, 550 μm high to lower eye margin. Eyes large, with wide dorsomedial extension, well-separated by ca. 100 μm. Facets equal. Frontal strip between eye extensions dark-coloured, long, sclerotized. Coronal triangle ca. 100 μm high, coronal suture ca. 70 μm high. Scape ca. 125 μm, pedicel ca. 40 μm in diameter. Clypeus ca. 200 μm high, ca. 150 μm wide. Proboscis very long, strong (longer than remainder of head), tapering, ca. 550 μm long, ca. 80 μm wide at (visible) apex; apical part with pair of sclerotized blades. Probable palpi no less than 400 μm long, two visible segments elongate, cylindrical, ca. 150 μm long, ca. 30 μm wide. Thorax. Scutum 900 μm long; postnotum ca. 250 μm long. Wing clearly longer than abdomen. Vein C produced beyond R4+5 (costal extension ca. 200 μm), reaching wing tip; cell c at r-m level broader than cell r1; cell r5 at R1 tip level almost twice as wide as cell r1; R1 straight, 2/3 as long as R4+5. Vein C, radial veins, M, r-m strong and coloured; other veins thin, pale. Legs. Mid- and hind femora ca. 180 μm wide; tibiae 100-120 μm wide near apex. Apex of mid- or hind tibia with traces of at least 5 spiniform setae. Abdomen. Segments II–VIII 250-300 μm long, 800-900 μm wide. Three rounded sclerotized spermathecae 70-90 μm in diameter, with long necks, largest spermatheca situated proximally of other two. Gonapophysis IX distinctly visible, sclerotized, with notum ca. 200 μm long and rami ca. 50 μm long. Posterior margin of sternite VIII bilobate: probable gonocoxites VIII (gonacoxapodemes?) visible distal to spermathecae. Cerci distinct, elongate-oval, 150 μm long, ca. 70 μm wide.

Remarks.

Adults of this new species are the largest among Podonomius (wing length is similar only in? Podonomius simplex Kalugina, 1985 (J2, Kubekovo, South Siberia), but in the Siberian species R1 is curved up distally).? Podonomius robustus sp. n. differs from other species from Shar Teg also in the longer costal extension. Such a long costa extending to the wing tip is an important plesiomorphic character ( Brundin 1976) and may be a character of generic value. Thus, the new species is only tentatively placed in Podonomius .