Micropsectra sofiae, Stur & Ekrem, 2006

Stur, Elisabeth & Ekrem, Torbjørn, 2006, A revision of West Palaearctic species of the Micropsectra atrofasciata species group (Diptera: Chironomidae), Zoological Journal of the Linnean Society 146 (4), pp. 165-225 : 208-211

MICROPSECTRA SOFIAE SP. NOV.

Holotype P(£) ( ZSM), Germany, Bavaria, Berchtesgaden National Park, Herrenroint, spring no.300, 12°58′20E, 47°34′40 N, 1250 m a.s.l., 29.IX. 2000, S. Wiedenbrug. 69 paratypes: 15££ ( ZSM, 1£ ZMBN = To92) Germany, Bavaria, Berchtesgaden National Park, Schapbach spring no. 360, 1140 m a.s.l., 12°57′29E, 47°34′58 N, 7.IX. 2001, 14.IX. 2001, 23.IX. 2001 & 29.IX. 2001, S. Wiedenbrug; 18££ ( ZSM), as previous except 20.ix.1996, 27.ix.1996, 4.x.1996 & 27.x.1996, I. Schrankel; 13££ ( ZSM), Germany, Bavaria, Berchtesgaden National Park , Herrenroint, spring no.312, 12°58′30E, 47°34′50 N, 1150 m a.s.l., 7.IX. 2001 & 23.IX. 2001, S. Wiedenbrug; 2££ as previous except 6.ix.1996, I. Schrankel; 4££ as previous except spring no.308, 12°58′20E, 47°34′40 N, 1250 m a.s.l., 7.ix.2001 & 23.ix.2001, S. Wiedenbrug; 3££ as previous except 6.ix.1996, 13.ix.1996 & 31.viii.1996, I. Schrankel; 1£ Germany, Bavaria, Berchtesgaden National Park , spring no. 351, 29.ix.2000, P. Martin; 2 P(£) & 1 P(£) ( ZSM) Germany, Bavaria, Berchtesgaden National Park , Klausbach at Lahnwald cabin, 30.vi.2000, E. Stur; 1$ ( ZSM) Germany, Bavaria, Allgäu, Rappensee, 24.-27.vi.1976, Mendl; 1£ as previous except 24–27.vi.1976; 4££ ( ZSM), Finland, Lappland, spring at Oulanka research station, 14.viii.1967, F. Reiss; 1£ ( ZSM), Italy, Südtirol, Dolomites, Misurina lake , 10.vi.1967, F. Reiss; 5££ (4 ZMBN, 1 MGDL) Luxembourg, Gutland, SW Kopstal, rheocrene spring, no. LUXqu25, sweep net, 25.vi.2002, T. Ekrem; 1£ ( ZSM), France, Ailefroide, French Alps, 30.vii.1956, Clastrier; 1 P(£) ( PHL), France, Pyrenees, Mitja, ‘ Bassin’ small reservoir nr. G1, 17.xi.1996, P. H. Langton; 1£ as previous except 13.vii.1956; 2££ ( WG), Poland, Tatra Mts. , Kooecieliska valley , netting, 07.ix.2000, D. Graczyk.

Etymology

The species is named after our good friend and colleague, Sofia Wiedenbrug, who also collected the holotype.

Diagnostic characters

Micropsectra sofiae can be separated from other species in the atrofasciata group by the following combination of characters: adult male with frontal tubercles minute; antennal ratio 0.4–0.7; brown pigmented fore coxa; absent to minute pulvilli; anal point well developed, broadly triangular, apically blunt, well developed knob between crests present; superior volsella with large field of microtrichia on stem, setiger large without ‘nose’, several long microtrichia in small field ventrally on setiger anterior to base of digitus, few wrinkles ventroapically on setiger; digitus thin, moderately long, not reaching median margin of superior volsella; median volsella comparatively short and stout, not reaching beyond posterior margin of superior volsella, apically blunt, with about 25 posteriorly directed spoon-shaped lamellae on distal half, setiform lamellae along whole length medially. Pupa with cephalic tubercles very low mounds; prealar tubercle absent; small dorsal field of granulation on mid thorax; thin, more or less rectangular unpigmented area dorsally on thorax; thoracic horn with long chaetae in one row on distal 2/3 of horn; strong spines in patches on tergites III–V (in the longitudinal, lateral extensions in TIV–V), sometimes somewhat reduced on tergite V; shagreen in small patches on tergite VI; dorsolateral comb of segment VII narrow with 3 separated, large, marginal teeth.

Description

Adult male. Measurements and ratios in Table 1.

Coloration: Body light greenish, with light brown scutal stripes, preepisternum, median anepisternum, postnotum and fore coxa; brown eyes and antennae. The specimens from Luxembourg were very pale, but always had a dark fore coxa.

Head. Antenna with 13 flagellomeres. Frontal tubercles minute or small; temporal setae in one row; palpomere three with c. 4 sensilla clavata in row; palpomere 3 much longer than palpomere 4.

Thorax. Usually with 1–2 humerals.

Wing. Subcosta and media bare, brachiolum with 2 setae, squama bare.

Legs. Pulvilli minute, not reaching base of claws. Fore tibia with small scale, spur minute to absent; middle and hind tibial combs 18–25 µm long; middle tarsomere Ta 1 with 2–4 sensilla chaetica.

Hypopygium ( Fig. 18A, B ). Anal tergite with tergite bands separate, posteriorly directed, reaching crests of anal point; 4–7, 5 median tergite setae placed on an elevated hump anterior to anal point base; 10–14, 12 ventral apical setae. Anal point broadly triangular, with high, slightly curved, anal crests, apex blunt; large knob between crests present; microtrichia free area around base. Setiger of superior volsella large, roundish with 6–7 dorsal and 2–4 median setae, 1 strong seta on stem; large field of dorsal microtrichia on stem and several long microtrichia ventrally on setiger, anterior to base of digitus; few wrinkles ventroapically on setiger. Digitus thin, medium long, not reaching median margin of superior volsella. Median volsella comparatively short, parallel sided, blunt apex, with c. 25 posteriorly directed spoon-shaped lamellae on distal 1/2, setiform lamellae medially directed along whole length; stem of median volsella not reaching beyond superior volsella. Inferior volsella with small dorsoapical swelling, quite straight, bearing numerous distal setae. Inner margin of gonocoxite with 3–4 strong setae.

Pupa (n = 4). Coloration: pupal exuviae brownish with dark brown apodemes; cephalothorax, TVIII and anal lobe darker; thin, rectangular pigment-free area dorsally in middle of thorax. Measurements in Table 2.

Cephalothorax ( Fig. 18C–E ). Cephalic tubercle very low mound; pedicel sheath tubercle weakly developed. Thoracic horn well developed with long chaetae in one row on distal 2/3 of horn; precorneals arranged in triangular pattern, the 2 anteriormost setae situated closer to each other than to the third, median precorneal longer than other two; 1 median antepronotal, 2 lateral antepronotals (1 sensillum basiconicum); 2 pairs of dorsocentrals, anterior pair shorter and weaker than posterior pair, setae of each pair equally strong. Some granulation present along median suture line and in small dorsal field on mid thorax. Prealar tubercle absent or barely visible mound; nose of wing sheath very weakly developed.

Abdomen ( Fig. 18F–H ). TII almost covered by shagreen except for one posteromedian oval patch; pedes spurii B on TII present; hook row less than half as long as segment width. Spines of TIII in large, laterally curved patches in posterior half of tergite, shagreen extensively distributed lateral and anterior to spine patches, a few points between spine patches. Patches of TIV consisting of spinules in anterior, oval, slightly diagonal patches with spines in longitudinal, lateral extensions which are slightly laterally curved posteriorly. Patches of TV similar to those of TIV in shape and construction, somewhat shorter, spines of variable length in longitudinal rows. Patches of TVI consisting only of shagreen, oval, distinctly shorter than patches on TV. TVII bare or with very weak anterolateral shagreen patches; TVIII with small anterolateral patches of shagreen. Segment I with 3 D and 1 V setae; segment II with 3 D, 4 V, 3 L; segment III with 5 D, 4 V, 3 L; segment IV with 5 D, 4 V, 1–2 lateral semitaeniate setae, 1–2 lateral taenia; segment V with 5 D, 4 V, 3 lateral taeniae; segment VI with 5 D, 4 V, 4 lateral taeniae; segment VII with 5 D, 4 V, 4 lateral taeniae; segment VIII with 1 dorsal taenia, 1 ventral taenia, 5 lateral taeniae; anal tergite with 1 dorsal taenia. Two pairs of small sensorial setae medially on TII– VII; 1 pair of O-setae present anteriorly on sternites II–VII. Anal lobe abruptly curved posteriorly, fringe with about 300–400 µm long taeniae in 1 row. Posterolateral comb of segment VIII ( Fig. 18I ) narrow, with 3–5 marginal teeth of which 3 are longer and stronger.

Larva unknown.

Remarks

Micropsectra sofiae has been recorded from cold groundwater springs in Finnish Lappland and the German Alps and at localities in the Italian Alps, Tatra Mts and the Pyrenees. Average water temperature in two of the studied springs in the German Alps was 5.3 °C (spring no. 360) and 6.5 °C (spring no. 308), respectively. Most of the studied springs have a neutral to weakly alkaline pH (Isabel Schrankel, 1998). The species is obvioulsy associated with cold-water habitats at high elevations or in springs. DNA has been isolated from one of the paratypes (To 92), and will also be used in future molecular phylogenetic analyses of the genus Micropsectra .

The species is morphologically most similar to the Japanese Micropsectra shouhiemalis Sasa, 1989 and Micropsectra shoubrevis Sasa & Okazawa, 1991 , but can be separated from both of these by the much lower antennal ratio (0.5–0.7 compared to 0.9–1.4 on specimens with approximately the same wing length), shorter digitus, and more circular superior volsella. We have examined the holotypes of both Japanese species.

Figures

Figure 18. Micropsectra sofiae sp. nov. A, hypopygium. B, superior, median and inferior volsellae. C, pupal thorax. D, pupal thoracic horn and precorneal setae of paratype. E, pupal frontal apotome. F, pupal abdominal segments II–V, dorsal. G, variation in armament of tergite V. H, pupal abdominal segments VIII–IX. I, posterolateral combs of pupal segment VIII.