Stempellinella sublettorum, Ekrem, 2007

Ekrem, Torbjørn, 2007, A taxonomic revision of the genus Stempellinella (Diptera: Chironomidae), Journal of Natural History 41 (21 - 24), pp. 1367-1465 : 1441-1442

Stempellinella sublettorum sp. n.

Type material

Holotype: „ ( CNC) Canada, New Brunswick, Northumberland Co., NW Miramichi River , 29 July 1962, J. Marshall.

Paratypes: 2 „„ (1 CNC, 1 VM) as holotype .

Etymology

The species is named in honour of Mary and Jim Sublette for their great contributions to Chironomidae research.

Diagnostic characters

Stempellinella sublettorum can be separated from other Stempellinella species by the following combination of characters: adult male with AR ca 0.9; anal point with several welldeveloped, often trifid, spinulae in an area which extend from between well-developed anal crests to the anal tergite itself; strong median tergite setae present; lateral anal tergite setae absent; setiger of superior volsella comparatively large, elongate oval, straight or slightly concave median margin, with broad base; median volsella 50 Mm long, conspicuously bent posteriad at half length, stem microtrichose, distally palmate.

Description

Adult male (n 5 3, unless otherwise stated). Total length 1.4–1.6 (n 52) mm; wing length 1.01–1.06, 1.03 mm.

Colour: pale yellow-brown ground colour, scutal stripes, median anepisternum and eyes brown. Eyes darker ventrally.

Head ( Figure 27A, B ): eyes without dorsomedian elongation; frontal tubercle large, conical, 8–15, 12 Mm long; antenna ( Figure 27B ) with 13 flagellomeres of which only 10 are easily discernible; AR (on 10 flagellomeres) 0.91 (n 51); lengths of palpomeres (in Mm): 20; 25; 60–63; 70–75; 90–120, 105. Clypeus about 40 Mm long with 8–10, 9 setae; tentorium ca 90 Mm long, 15 Mm wide; two or three inner verticals, two outer vertical, two postorbitals.

Thorax: scutal tubercle absent; acrostichals 8–10, 9; dorsocentrals 5–6; humerals 0–1; prealars 1; scutellars 6; halterals 5.

Wing ( Figure 27C ): cuneiform, 3.0–3.1 times longer than broad; VR 1.52–1.61, 1.57; wing setation as in Figure 27C .

Legs ( Figure 27D ): fore tibia with 15 Mm long spur; mid and hind tibiae with wellseparated, 10 Mm long tibial combs, one comb on each tibia with 28–30 Mm long spur; tarsi without sensilla chaetica; pulvilli minute, reaching base of claws. Lengths and ratios of leg segments in Table III.

Hypopygium ( Figure 27E, F ): anal tergite 93–100, 96 Mm long with transverse anal tergite band, four to seven, five strong median setae far from anal point base, sometimes one small setae near base; lateral anal tergite seta absent; anal point 45–48, 47 Mm long, basally 12–13 Mm broad with well-developed crests, distally thin and pointed; 8–11 strong, often trifid, spinulae between anal crests and at base of anal point; microtrichia-free areas on each side of anal point. Gonocoxite 75 Mm long; gonostylus 50 Mm long; HR 1.50 superior volsella comparatively large, setiger more or less elongate oval, median margin straight or slightly, base broad, five dorsal and two median setae, superior volsella otherwise bare; digitus absent; median volsella 50 Mm long, conspicuously bent posteriad at half length, stem distally palmate with numerous microtrichia; inferior volsella 50–60, 57 Mm long, slightly club-shaped, medially curved distally, with five distal setae, dorsal surface without microtrichia, long, thin digitus with split apex near base.

Adult female, pupa, and larva. Unknown.

Remarks

Stempellinella sublettorum can easily be separated from all other Stempellinella species by its microtrichose, conspicuously bent median volsella. The species has so far only been recorded from its type locality in New Brunswick .

Figures

Figure 27. Stempellinella sublettorum sp. n., male imago. (A) Head; (B) antennal flagellum; (C) wing; (D) fore, mid, and hind tibiae; (E) hypopygium; (F) superior, median, and inferior volsellae.