Parachironomus aquiloni

Orel, Oksana V., 2017, Two new species and new records of the genus Parachironomus Lenz, 1921 (Diptera, Chironomidae) from northern Russia, Zootaxa 4312 (3), pp. 531-546 : 532-534

Parachironomus aquiloni s sp. n.

( Figs 1–4 , 11–16 )

Parachironomus ? hazelriggi Spies, 2000 sensu Krasheninnikov et al. (2015: 416) —misidentification.

Type material. Holotype: male, Arkhangelsk region , Avtonomniy Nenets district , Ugra Peninsula , Pay-Khoy ridge, beach lagoon Amderma, N 69°45’05,6”, E 61°34’00,2”, 0 m above sea level, 25.vii.2013, leg. A. Krasheninnikov.

Etymology. The species is named for the northern region of Russia in which the material was collected. The epithet is the genitive singular form of the Latin noun aquilo, a North wind, i.e. a noun in apposition for the purposes of nomenclature.

Diagnostic characters. The adult male of P. aquiloni s sp. n. is distinguished by the following combination of features: frontal tubercles absent; wing length 2.30 mm; AR 2.63; LR P1 1.31; wing without cell setae; tergite IX without longitudinal anal tergite band, anal point without dorsal setae on base, longer than superior volsella, in lateral view wide with base much higher proximally than distally and distal dorsal contour distinctly angled towards ventral, bare part of anal point occupying about half of total point length; SVo with apical subacute to acute lamellar lobe usually as wide as apex of volsella; IVo with shallow distal lobe at least to posterior; gonostylus curved to medial in proximal half, in lateral view up to 58 µm high near mid-length.

Adult male (n=1). See also Table 5.

Coloration. Scape brown; ground color of thorax pale yellow, mesonotal stripes and postnotum brown; abdomen brown; legs brown except for lighter proximal parts of f and ta1.

Head. Frontal tubercles absent. Temporal setae 25. Clypeus with 19 setae. Antenna 1218 µm long. AR 2.63. Maxillary palpomeres 2–4 combined 608 µm long, their individual lengths (in µm): 56; 152; 184; 216. Antenna length/palp length 2.0.

Thorax. Antepronotals 10, acrostichals 25, dorsocentrals 23–25, prealars 8–10, supraalar 1. Scutellum with 24 setae.

Wing. Length 2.3 mm. VR 1.11. R with 23–26, R1 with 15–16, R4+5 with 30–35 setae in distal 2/3, M1+2 without setae. Squama with 22 setae.

Legs. See Table 1. Each mid and hind tibia with 2 fused combs and 2 spurs (length 37 µm). BR P1 3.46, BR P2 3.45, BR P3 3.40.

Hypopygium ( Figs 1–4 , 11–16 ). Laterosternite IX with 0–1 setae. Anal tergite bands separate, median longitudinal part absent. Anal point (in dorsal view length 163 µm, at about apex width 6.8 µm; in lateral view the base width 45 µm, at about apex width 6.8 µm) with wider, tapering basal half (length 78 µm) that carries microtrichia and 9–10 lateral setae, and with parallel-sided bare distal half (length 85 µm). Portal setae (see Spies 2000) 3–4 on each side, these are separated by distances at last equal to the diameter of their bases. Transverse sternapodeme 109 µm long. Phallapodeme 139 µm long. Superior volsella (116 µm long) in dorsal view straight, in lateral view slightly curved and expanded in the apical part, little to moderately expanded at the base, apically with lamellar lobe (17 µm) usually as wide as apex of volsella, with 1 terminal (44–48 µm long) and 1 medial (44 µm) seta located in pits as wide as the volsella, distance between them 10 µm ( Figs 1–4 ). Inferior volsella with shallow prominence at least to posterior, its microtrichia not elongate. Gonostylus 289 µm long, in dorsal and lateral views slightly curved, in the proximal part expanded and bears 8 latero-ventral setae, in dorsal view usually slightly expanded in distal half, in lateral view gonostylus more extended (58 µm) at about middle and gradually tapers to the top, with a row of 6–7 distal-median setae ( Fig. 11 ). HR 0.59.

Female, pupa and larva unknown.

Remarks. The adult male of P. aquilonis sp. n. is most similar to that of the Holarctic species P. hazelriggi Spies, 2000 , but can be distinguished by the relatively shorter bare section of the anal point, and by the higher base of the anal point in lateral view ( Figs 9–11 ; Table 5).

Figures

FIGURES 1 – 8. Adult males of P. aquilonis sp. n. (1 – 4) and P. hazelriggi. (5 – 8). 1, 5 — hypopygium, dorsal view; 2 – 4, 6 – 8 — variations in the structure of the superior volsellae (2, 7 – 8 — dorsal view, 3 – 4, 6 — lateral view). Scale bars 50 µm.

FIGURES 9 – 11. Hypopygium in lateral view of P. hazelriggi (from Spies 2000) (9), P. hazelriggi (our data) (10) and P. aquilonis sp. n. (11). Scale bars 50 µm.

FIGURES 12 – 16. Details of hypopygium structure of P. aquilonis sp. n. (12, 14 — dorsal view; 13 — ventral view; 15 – 16 — lateral view). Scale bars 500 µm.