Jurochlus sibiricus Kalugina, 1985

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 : 436-438

Jurochlus sibiricus Kalugina, 1985

( Figs 1 A, B, 2)

Type material. Holotype: PIN 3053/727 (pupa of female, Siberia, Uda, Uda Formation, Middle or Upper Jurassic).

Additions to description. Upon re-examination of the holotype, several features not mentioned in the original description can be added.

Thoracic horn tear-shaped, with rather stout basally tapered stalk and reticulate subcordate plastron plate (outline of horn with a slight apical concavity), slightly broader than remainder of horn; respiratory atrium elongate, basally tapering; stalk with 3–4 traces of probable transverse ridges. Anterior part of cephalothorax with traces of antennal sheaths. Wing sheaths rather short, appearing apically narrowed, not projecting ventrally, possibly with nose. Leg sheaths arrangement as in the generic diagnosis.

Abdominal segment II probably with ventral lamella, which is strongly darkened, adjoining wing sheaths, and curved anteroventrally. Each segment with transverse dark lines at anterior margin and along posterior margin (probable tergal ridge); some lines at posterior margin irregularly thickened (possible traces of blunt spines). Tergites II, IV, V and VII darkened in posterior parts (around ridge and at posterior margin; possibly darkening resulting from overlapping of tergite margins). Abdominal segments II–VIII with longitudinal interrupted dark stripe dividing lateral parts of segments (probably, sternal fold along lateral adhesion mark). No setae or spines visible at lateral margins of abdominal segments I–VIII. Posterior margin of sternite VIII more protruding medially, with dark crease between accessory genital sacs (the latter appearing as two median lobes).

Segment IX. Distinctly serrate outer margin was mentioned by Kalugina; inner margin also serrate, more finely. Genital sac slightly more pigmented than outer adjoining area, its lateral margins can be traced only apically; sac elongate, apically tapering, reaching segment apex near its middle but not projecting beyond it. Segment IX anterior to genital sac, with genital plate IX distinctly outlined, appearing as dark transverse V-shaped stripe.

Measurements. Body length, 4400. Cephalothorax length (to the end of postnotum/to the end of wing sheaths), 1250/2000. Thoracic horn length/width, 550/330. Abdomen length, 3450. Abdominal segments II–VIII length, 375–425; III–VI width, 950–1000; VII–VIII width, ca. 750. Abdominal segment IX: length, 530; width at base, ca. 650; distance between apices of anal lobes spur, ca. 230.

Figures

FIGURE 1. Holotypes of Jurochlus species (pupae of females): A, B, J. sibiricus Kalugina, 1985: holotype PIN 3053 / 727: A, total view; B, segment IX; C, total view of J. rigor Kalugina, 1985: holotype PIN 3053 / 774; D, total view of J. limbatus sp. nov.: holotype PIN 4270 / 2584; E, total view of J. trivittatus sp. nov.: holotype PIN 4270 / 2581.