Zavrelia pseudopentatoma, Zorina, Oksana V., 2008

Zorina, Oksana V., 2008, Russian Zavrelia Kieffer (Diptera: Chironomidae), with the description of two new species, Zootaxa 1845, pp. 60-68 : 65-67

Zavrelia pseudopentatoma sp. n.

( Figs 13–24 )

Zavrelia pentatoma Kieffer in Bause, 1913; Makarchenko et al. (1999: 1); Makarchenko et al. (2005: 394) [misidentifications.]

Type material. Holotype male, RUSSIA: Primorye Territory, Sikhote-Alin Nature Reserve, Bolshoe Solontsovoe Lake, 25.vii.2004, O. Zorina & E. Pimenova. Paratypes: 7 males, Primorye Territory, Sikhote-Alin Nature Reserve, Sokhatinoe Lake, 25.vii.2004, O. Zorina & E. Pimenova; 4 PL-males, as previous except 25.vi.2006; 1 male, Primorye Territory, Sikhote-Alin Nature Reserve, Dlinnoe Lake, 25.vii.2004, O. Zorina; 1 male, Primorye Territory, Lazovskiy Nature Reserve, Chekhunenko Lake, 3–4.vi.2001, E. Makarchenko; 5 males, Primorye Territory, Lazovskiy Nature Reserve, Zarya Lake, 5.vii.2007, O. Zorina; 10 males, Kamchatka Peninsula, Bystraya River, 7.vii.1996, E. Makarchenko.

Etymology. The name indicate the similarity with Z. pentatoma Kieffer.

Diagnostic characters. Male anal point with microtrichia, but without spinules between anal crests; superior volsella with extended inner part, bearing two setae; AR 1.07–1.22; legs brown. Pupa with 330–341 µm long thoracic horn; segment II–III each with 3 L setae; segment IV–V each with 3 LS setae; segment VIII with 1–4 dark posterolateral spurs without spinules. Larval frontal apotome with median ovate depression; AR 1.18; antenna with first Lauterborn organ at about middle of segment 2; inner margin of mandible with 2 spines.

Male (n = 5)

Total length 1.60–1.70 mm; wing length 1.25–1.40 mm. Total length / wing length 1.21–1.28.

Coloration. Antenna, thorax, abdomen and legs brown.

Head. Frontal tubercles conical, 9 µm long, 7 µm wide. Antenna with 10 flagellomeres, 638–682 µm long; ultimate flagellomere 330–363 µm long; AR 1.07–1.22. Verticals 6–9. Clypeus with 6–10 setae. Maxillary palp 365–423 µm long; lengths of palpomeres 2–5 (in µm): 32–41, 113–126, 90–104, 126–158. Antenna length / palp length 1.75–1.81.

Thorax. Acrostichals 10–13, dorsocentrals 6–11, prealars 1. Scutellum with 4–8 setae.

Wing 330–350 µm wide. All veins except M with microtrichia. VR 1.2–1.4.

Legs. Spur of foretibia 18 µm long, spurs of midtibia 23 and 18 µm long, spurs of hind tibia 23 and 18 µm long. Lengths and proportions of legs as in Table 2 .

Hypopygium ( Figs 13–15 ). Tergite IX with 5–12 median setae. Laterosternite IX with 1 seta. Anal point 50–54 µm long, 9 µm wide, tapering to apex; with microtrichia but without spinules between anal crests. Transverse sternapodeme 54–68 µm long, without oral projections. Phallapodeme 81–90 µm long. Gonocoxite 86–90 µm long, with 3–5 inner setae. Superior volsella elongated, 36–45 µm long, 18–20 µm wide with inner part produced; inner margin with 2 setae; outer margin with 5 setae. Stem of median volsella about 18– 23 µm long, with 5–7 lamellae apically. Inferior volsella 45–59 µm long, with 11–13 setae in distal part. Gonostylus 50–63 µm long, inner margin with 4 setae. HR 1.36–1.73.

Pupa (n = 2)

Total length 2.40 mm.

Cephalothorax ( Figs 16–17 ). Frontal setae 158 µm long. Thoracic horn 330–341 µm long, 28 µm wide, covered with spines in distal 1/2. Prealar tubercle well developed. Precorneals 3, antepronotals 3 (1 median and 2 lateral), dorcocentrals 4. Distance between DC2 and DC3 108–113 µm.

Abdomen ( Figs 18–20 ). Tergites II–VI with shagreen, shagreen not extending anterior of seta D1, shagreen on tergite VI separated medially. Tergites VII–IX with pair of anterolateral patches of spinules. Pleura of segments II–VI with shagreen. Hook row consisting of 42–44 hooks. Segment VIII with 1–4 dark spurs lacking dorsal spinules. Segments II–III each with 3 L setae, segments IV–V each with 3 LS setae, segments VI–VII each with 4 LS setae, segment VIII with 3 LS setae. Anal lobe with 20–24 lamelliform setae and dorsal seta in distal part.

Fourth instar larva (n = 2)

Total length 2.10–2.25 mm. Coloration green (in formaldehyde), with yellowish brown head capsule. Head capsule 250 µm long, 150 µm wide, cephalic index (W/L) = 0.6.

Head. Frontal apotome with median ovate depression. Seta S 3 simple ( Fig. 22 ). Antenna 149–167 µm long, length of segments (in µm): 81–90, 41–45, 14, 9–11, 5–7. AR 1.18. Pedestal 81–86 µm long, distal spur 27–36 µm long. Basal segment with ring organ at base. Blade 135 µm long, extending far beyond apex of antenna. Second segment with 18–23 µm long Lauterborn organ on short pedicel medially; second Lauterborn organ 27 µm long, on long pedicel. Style 14 µm long ( Fig. 21 ). Seta S I 18 µm long, S II 32 µm long, S III 23 µm long. Premandible 54–59 µm long, with 4 pale teeth. Mandible 81–92 µm long, 45–63 µm wide; seta subdentalis 41–45 µm long; inner margin with 2 spines ( Fig. 23 ); apical and 3 inner teeth brownish. Maxillary palp with four segments, 23 µm long. Mentum 63–68 µm long; median tooth yellowish, lateral teeth yellowish brown ( Fig. 24 ). Ventromental plate 50–59 µm wide, 32 µm high; distance between ventromental plates 32 µm.

Body. Posterior parapods with 15 yellow, simple claws. Anal tubules conical; 72 µm long, 27 µm wide. Procercus 27 µm long, 27 µm wide; with 4 anal setae. Segments II–VI with pair of plumose setae in posterolateral corner.

Remarks. The new species resembles Z. pentatoma Kieffer in the structure of the hypopygium. However, it differs by having microtrichia but no spinules between the anal crests and in the shape of the superior volsella, which has an extended inner margin bearing two setae. The anal point of Z. pentatoma is densely covered by spinules between the anal crests and the superior volsella is ovate without extended inner margin ( Pinder 1978; Cranston et al. 1989).

The pupa is also similar to Z. pentatoma , but can be distinguished by having a 330–341 µm long thoracic horn covered by spines in distal half; hook row of 42–44 hooks; shagreen on tergites II–VI not extending anteriorly of seta D1; segment II–III each with 3 L setae; and segment IV–V each with 3 LS setae. The pupa of Z. pentatoma have a 345–470 µm long thoracic horn with spines in distal third; hook row of 60–71 hooks; shagreen on tergites II–VI extending anteriorly beyond seta D1; segment II–IV each with 3 L setae; and segment V with 3 LS setae ( Pinder & Reiss 1986; Langton & Visser 2003).

The larva can be separated from the larva of Z. pentatoma by the presence of an ovate depression in the frontal apotome; by having first Lauterborn organ situated medially on segment 2; and antennal segments 3–5 combined shorter than the second Lauterborn organ. The frontal apotome of Z. pentatoma lacks median depression; first Lauterborn organ is situated in proximal half of segment 2; and antennal segments 3–5 combined are longer than the second Lauterborn organ ( Pankratova 1983; Pinder & Reiss 1983).

Distribution and ecology. Zavrelia pseudopentatoma sp. n. was taken in the Primorye Territory and on the Kamchatka Peninsula, Russian Far East, where the larvae occur in lakes and rivers.

Figures

FIGURES 13 – 24. Zavrelia pseudopentatoma sp. n. male (13 – 15), pupa (16 – 20) and larva (21 – 24). 13. Hypopygium. 14. Tergite IX, lateral view. 15. Superior volsella 16. Thoracic horn. 17. Thorax, lateral view. 18. Tergites II – IX. 19 – 20. Anal spur. 21. Antenna. 22. Dorsal sclerites. 24. Mentum and ventromental plates. Scale bar 50 µm.

Tables

TABLE 2. Lengths (in µm) and proportion of legs of Zavrelia pseudopentatoma sp. n., male, (n = 5).

fe	ti	ta1	ta2	ta3
p1 540–570	360	510–525	315	255
p2 570–630	450–510	255–285	135–150	105–135
p3 675–750	570–630	330–360	195–210	180–195