Jurochlus Kalugina

Lukashevich, Elena D. & Przhiboro, Andrey A., 2012, Pupae of Mesozoic Jurochlus Kalugina, 1985 (Diptera: Chironomidae), with description of four new species, Zootaxa 3478, pp. 434-452 : 435-436

Genus Jurochlus Kalugina in Kalugina et Kovalev, 1985

Type species Jurochlus sibiricus Kalugina in Kalugina et Kovalev, 1985: 95, fig. 48.

Differential diagnosis (emended). Medium-sized to large pupae, 4.5– 11 mm long. Thoracic horn widened distally, with well-developed plastron plate and stout basal stalk. All leg sheaths situated under wing sheath, meeting together at tip of wing sheath, distal portion of fore and midleg darkened sheaths practically straight, Sshaped portion of hind leg sheath beneath distal half of wing sheath. Segments II–VIII short and wide, nearly rectangular, with straight or slightly convex lateral margins. Anterior and posterior margins of abdominal segments nearly straight; anterior margins of tergites II–VIII appearing as sclerotized transverse stripes; posterior margins of tergites often pigmented; tergites II–VII usually with a well-developed transverse ridge in posterior part. Segment VII with two or three LS setae. Segment VIII with five LS setae in distal two-thirds, posterior angles not produced into large lobes (at most, with small, barely projecting lobes); female sternite VIII at posterior margin with accessory genital sacs separated by distinct longitudinal crease.

Segment IX in proximal third with two lateral close-set setae on either side; setae short, about 0.2x the lobe length. Anal lobe more or less triangular, apically pointed into a dark spur. Outer and inner margins of anal lobes usually with continuous row of saw-like teeth; inner margins more finely serrate; serration on both margins not reaching spurs. Outer margin of anal lobe more or less straight or slightly sinuate (convex in proximal two-thirds and concave in apical part); inner margins converging, usually sinuate. Male genital sac wedge-shaped, with inner margin confluent, distally tapered, reaching 3/4 of lobe length and projecting outside anal lobe margin. Female genital sac shorter, slightly tapered, not projecting outside anal lobe margin; female genital plate IX transverse, distinct.

Species included. Besides the type species, J. rigor Kalugina, 1985 from the same locality (Middle or Late Jurassic of Transbaikalia) and four species described below from the Late Jurassic and Early Cretaceous of Mongolia, all known from pupae only.

Remarks. The genus was established based on two impressions of pupae attributed to two species. Up to now, only these two species have been known.

Despite the abundance of impressions of adult chironomids at Shar Teg and Khutel Khara, and our examination of every impression from Shar Teg, no specimens of appropriately large size have been found, and thus no association can be made.

Only the holotype of J. sibiricus is preserved completely, all other species are known only by abdomens. Hence, the structure of the thoracic horn, thorax and wing sheaths can be described only for the type species, known from a single impression.