Podonomius blepharis, 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 : 310

Podonomius blepharis sp. n.

Etymology.

From Greek “blepharis” for eyelash, after the pattern of the tibial comb.

Material examined.

Holotype: part and counterpart of well-preserved female PIN 4270/2357 ±, SW Mongolia, Shar Teg (443/1); Late Jurassic.

Diagnosis.

The new species is distinguished by its small size (wing length l.4 mm), well-developed elongate proboscis, weakly convex scutum without a hump, wing with broad cell c, and pale legs with darker junction of femur with trochanter and tibia, and with combs of dark closely-spaced spiniform setae at tibial apices.

Description.

Female (Figs 1 i–l, 2 d–f). Measurements (mm): Total length 2.0; thorax length 0.8, height 0.9; abdomen length 1.0; wing length 1.4. Total length / wing length 1.4. Coloration . Head and thorax dark, abdomen lighter, legs pale with darker junction of femur with trochanter and tibia, with darker apices of tibiae. Head no less than 600 μm wide, no less than 550 μm high with proboscis, 380 μm high to lower eye margin. Eyes large, with wide dorsomedial extension, looking narrowly separated by ca. 30 μm. Facets equal. Coronal triangle ca. 100 μm high, coronal suture clear near upper eye margin. Scape 90 μm, pedicel 45 μm in diameter; proximal flagellomeres short-oval to rounded, ca. 35 μm wide and 40-50 μm long. Clypeus ca. 100 μm wide, ca. 150 μm high, possibly with longitudinal groove. Proboscis well-developed, elongate, sclerotized at least in distal part, ca. 200 μm long (projecting distally of clypeus for no less than 120 μm), ca. 30 μm wide at visible apex. Thorax. Scutum weakly, evenly convex, without hump or tubercle. Scutellum ca. 150 μm long, not projecting. Postnotum ca. 200 μm long. Wing. Vein C probably not produced beyond R4+5; cell c at r-m level subequal to cell r1, which only slightly narrower than r5 cell at level of R1 tip; R1 approximately 2/3 as long as almost straight R4+5; r-m inclined to M. All veins mentioned strong, coloured. Legs. Measurements (μm). p1(?): ta1 380, ta2-5 ca. 405; p2: fe 700, ti 680; p3: fe 560, ti 680, ta1 ca. 500, ta2-5 ca. 650, LR3 ca. 0.75. Femora maximum ca. 110-120 μm wide, with thin sclerotized ridge ventrally near apex. Tibiae ca. 80 μm wide. Apices of mid-, hind tibiae with combs of dark closely-spaced spiniform setae ca. 50 μm long; in midtibial comb, no less than 10 setae, in hind tibial comb, 8 setae. Spurs not observed. Abdomen. Segments III–VII: tergites 150-180 μm long. Three large subequal oval moderately sclerotized spermathecae 100 μm long, ca. 80 μm wide, with necks (probably, long), in compact group. Sternite VIII with posteromedian sclerotized plate, its posterior margin bilobate; probable gonocoxites VIII (gonacoxapodemes?) visible as moderately sclerotized small oval lobes approximating each other. Cerci not visible.

Remarks.

The new species is similar to Podonomius splendidus Kalugina, 1985 (J1/2, Novospasskoye, Transbaikalia) in its venation (C length, ratio R1/ R4+5), colour pattern of legs and elongated mouthparts, which are visible on paratype PIN 3000/1857 (in the other type specimens of Podonomius from Siberia, the mouthparts are not visible due to the state of preservation). Podonomius blepharis sp. n. differs from Podonomius splendidus in broader cell c and smaller size. As for tibial combs, Kalugina noted (1985) that in Podonomius tugnuicus and Podonomius splendidus the tibial apices are darkened but without mentioning combs. According to our re-examination of the type material of Podonomius splendidus , the hind tibia has a reduced comb consisting of a row of separate dark points, which may be minute setae or possibly bases of missing long bristles (these seem to be visible near the tibial apex in the holotype). In the latter case, a well-developed tibial comb is not unique for Podonomius blepharis .