Micropsectra calcifontis, 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 : 190-192

MICROPSECTRA CALCIFONTIS SP. NOV.

Holotype £ ( ZSM), Luxembourg, Gutland , SW Kopstal, rheocrene spring, no. LUXqu25, emergence trap (E7), 4.v.1999, I. Schrankel. 16 paratype ££ ( MGDL) as holotype except: 3££, 18.v.1999; 1£, 7.ix.1999; 3££ (2 ZMBN including voucher To113), 21.ix.1999; 1£, 5.x.1999; 2££ ( ZSM), 19.x.1999.

Etymology

From Latin calx (chalk) and fons (spring), a noun in the genitive case, referring to the nature of the locus typicus.

Diagnostic characters

Micropsectra calcifontis can be separated from other species in the atrofasciata group by the following combination of characters: adult male with frontal tubercles as small dots; antennal ratio c. 0.85; pulvilli small, reaching base of claws; c. 10 median tergite setae; anal point well developed, short, apically blunt, knob between long crests small; superior volsella with large field of microtrichia on stem, setiger with prominent posterior ‘nose’, several long microtrichia in small field ventrally on setiger anterior to base of digitus, few wrinkles ventroapically on setiger; digitus small, triangular; median volsella long and moderately thick, tip reaching past posterior margin of superior volsella, evenly tapered in distal half, with about 30 dorsomedially directed spoon-shaped lamellae on distal half, setiform lamellae along whole length medially.

Description

Adult male. Measurements and ratios in Table 1.

Coloration. Thorax with light greenish ground colour; scutal stripes, postnotum, preepisternum and median anepisternum light brown; abdomen completely pale greenish; eyes brown, antenna yellowish.

Head. Antenna with 13 flagellomeres. Frontal tubercles present as small dots; temporal setae in one row; palpomere three with c. 5 sensilla clavata in bundle.

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

Legs. Pulvilli small, reaching base of claws. Fore tibia with small scale, spur 20–25 µm long; middle and hind tibial combs 20–25, 21 µm and 25–30, 28 µm long, respectively; middle tarsomere Ta 1 with 2–4 sensilla chaetica.

Hypopygium ( Fig. 9A–D ). Anal tergite with tergite bands separate, posteriorly directed, not reaching crests of anal point; 7–14 median tergite setae placed on an elevated hump anterior to anal point base; 13–16, 15 ventral apical setae. Anal point short, robust, triangular in appearance, with relatively long, slightly curved anal crests; apex short and apically blunt; knob between crests small; comparatively large microtrichia free area around base. Setiger of superior volsella roundish with prominent posterior ‘nose’, 7–9, 8 dorsal and 3–4 median setae on setiger, 1 strong seta on stem; large field of dorsal microtrichia on stem and several long microtrichae ventrally on setiger, anterior to base of digitus; few wrinkles ventroapically on setiger. Digitus, short, triangular, apically pointed. Median volsella long, moderately thick, evenly tapered in distal half, with medially directed setiform and spoon-shaped lamellae, c. 30 spoon-shaped lamellae on distal half; stem reaching beyond superior volsella. Inferior volsella slightly medially bent, with small median swelling, bearing numerous distal setae. Inner margin of gonocoxite with 3–4 strong setae.

Pupa and larva unknown.

Remarks

Micropsectra calcifontis has been collected from one coldwater spring in Luxemburg only. The type locality is an undisturbed rheocrene spring characterized by continuous water flow, relatively high conductivity (621 µS/cm), low temperature (8.4 °C in April 1999) and calcareous deposits ( Gerecke et al., 2005). The vegetation surrounding the spring is largely beech, ash and alder, and the spring is 100% shaded by the surrounding trees ( Gerecke et al., 2005).

Figures

Figure 9. Micropsectra calcifontis sp. nov. A, hypopygium. B, anal point, lateral view. C, median volsella. D, superior, median and inferior volsellae.