Jurochlus trivittatus, Lukashevich, Elena D. & Przhiboro, Andrey A., 2012

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 : 439

Jurochlus trivittatus sp. nov.

( Figs 1 E, 3A–E, 4, 5)

Type material. Holotype: PIN 4270/2581 (abdominal segments II–IX of female pupa). Paratype: PIN 4270/2540 (abdominal segments V–IX of male pupa). SW Mongolia, Gobi-Altai Aymag, Shar Teg (outcrop 443/1), Upper Jurassic.

Etymology. From the Latin vitta (band), in reference to the pattern of three longitudinal stripes on abdomen.

Description. Pupa of female. Each segment except terminal one with three wide nearly parallel (broadly oval or subrectangular) concavities, median and two lateral ones, darker than surrounding areas. Anterior margins of tergites well-sclerotized; posterior margins darkened. Tergal ridge very strong on segment II, becoming progressive smaller to more posterior segments (up to segment VII). Some segments with fine, more or less longitudinal (fan-shaped) striation (most distinct on II and V; probably traces of muscles) posterior to ridge; some such lines extending to anterior margin of next segment. Lateral parts of segments II–VII with elongate concavities (probably adhesion marks). No distinct LS setae visible.

Segment IX. Outer margin of anal lobe sinuate, distinctly convex in middle part and strongly concave in apical third. Outer margin finely serrate, serration clearly visible in middle third of margin, consisting of triangular stout spines with wide bases (ca. 40 spines visible); inner margin with spines of similar size and shape at least in its middle. Lobes apically tapered into dark spurs; distance between apical spurs 0.4x the width of segment IX at base. Genital sac slightly more pigmented than outer adjoining area, elongate, slightly tapering, with apically rounded parts, not reaching segment apex in its middle. Segment IX anterior to genital sac with darkened area at midline and at anterior margin.

Pupa of male. Similar to female, but three concavities on segments not as distinct, dark pattern not visible. Tergal ridge strong on segment V, becoming progressively smaller on more posterior segments (up to segment VII). Tergite VIII with indistinct traces of possible ridge. Segments V and VI with fine, more or less longitudinal (fan-shaped) striation posterior to ridge.

Segment IX with traces of two stout lateral setae in anterior third. Outer margin of anal lobe finely serrate, with triangular stout small spines at least in middle third; inner margin possibly with similar smaller spines (not distinctly visible). Genital sac with anterior parts more distinctly visible, darker than posterior ones, separated from these latter by diagonal lines. Areas anterior to genital sac well outlined laterally.

Measurements. Female. Combined length of abdominal segments II–IX, 8000; entire body length (extrapolated), 10000–11000. Abdominal segments length: II–VIII, 900–1100; width: II–V, 2600; VI, 2500; VII, 2400; VIII, 2250. Abdominal segment IX: length, 1380; width at base, 2000; distance between tips of anal lobe spurs, 800.

Male. Combined length of abdominal segments V–IX, 5190; entire body length (extrapolated), 10000–11000. Abdominal segments length: II–VII, 1050; VIII, 800; width: V–VI, 2380; VII, 2250; VIII, ca. 2130. Abdominal segment IX: length, 1380; width at base, 1870; distance between tips of anal lobe spurs, 750.

Note. We suggest the male and female pupae to be conspecific based on the similar appearance and body proportions (especially that of segment IX), the presence of well-developed tergal ridges on the same segments, and the serration of anal lobe margins consisting of spines, which are similar in shape.

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.