Micropsectra bavarica, 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 : 188-190

MICROPSECTRA BAVARICA SP. NOV.

Micropsectra sp. ( Thienemann, 1936: 184, in part).

Gowiniella bavarica Thienemann ( Vaillant, 1955; Säwedal, 1982b), nomen nudum.

Holotype P£ ( ZSM), Germany, Bavaria, Partenkirchen, upper Höllentalklamm, 7.vi.1933, A. Thienemann. 89 Paratypes ( ZSM): 1 P$, 4 P($$) & 2 Pex, as holotype; 2££, 1 P(£), 2 P($$), 16 L, Algeria, Tala Guilef, 1.vi.1953, F. Vaillant; 2 P££, 1 Pex, 2££ Algeria, Atlas de Blida, La Chiffa, 700 m a.s.l., v.1952, F. Vaillant; 1£, 6 L, France, Auvergne, Cascade de la Barthe, 1200 m a.sl., 29.viii.1953, F. Vaillant; 1£ as previous except Besse en chandesse, 1040 m a.s.l., 30.viii.1953; 2 L(P), 1 L, France, Grenoble, Corenc, 12.vii.1947, F. Vaillant; 7 Pex, 3 L, France, Massif du Vercor’s, Gorges du Bruyant, 29.viii.1951, F. Vaillant; 2 Pex, 9 L, France, Massif du Vercor’s, Gorges d’Engins, 1000 m a.s.l., 6.viii.1951; 2 L, France, Massif du Pelvaux, Galerie du Grand Clos, 1200 m a.s.l, 12.viii.1951, F. Vaillant; 1 L, France, Massif du Vercor’s, Sassenage, 8.vi.1947, F. Vaillant; 1 P£ & 1£ France, Grenoble, Domène, 1950, F. Vaillant; 1 P$, 3 L France, Grenoble, Laboratoire de Grenoble , 1950, F. Vaillant; 1£ as previous except 10.II. 1947; 1 Pex, 3 L, France, Pyrenees, Bareges, leg. Bertrand.

Etymology

The adjective bavarica refers to the state of Bavaria where the type locality is located. The species was originally named by August Thienemann (unpublished manuscript) .

Diagnostic characters

Micropsectra bavarica can be separated from other species in the atrofasciata group by the following combination of characters: adult male with frontal tubercles small (c. 10 µm); pulvilli small, reaching base of claws; AR low (0.5–0.6); anal point well developed, broadly triangular, comparatively wide at base, knob between crests moderately large; superior volsella with large field of microtrichia on stem, setiger roundish, several long microtrichia ventrally on setiger anterior to base of digitus, no wrinkles ventroapically on setiger; digitus long, apically pointed, medially curved, reaching past median margin of superior volsella; median volsella long, thin, parallel-sided, reaching well beyond superior volsella, apically pointed, with about 15 dorsomedially directed, spoonshaped lamellae on distal third, setiform lamellae along whole length medially. Pupa with comparatively large (30–35 µm), cone-shaped cephalic tubercles; thoracic horn with comparatively short chaetae on distal 4/5; prealar tubercle a low mound, rounded; small field of coarse granulation dorsally on scutum; large unpigmented area dorsally on thorax; spinules and points in extensive (broad and long) patches on tergites III–VI, patches connected anteriorly and almost covering tergites; all patches of about same size; shagreen on pleura II–VI; dorsolateral comb of segment VII comparatively broad with 3–5 separate, marginal teeth of which 2–3 are larger than the remaining; fringe of anal lobe often starting at some distance from anterior margin. Larva with straight, double, triangular spur on antennal pedestal; antennal segment 1 c. 170– 200 µm long; comparatively low AR (c. 1.8); labral seta SII plumose, chaetae pectinate; clypeal seta S3 long, simple; MVR about 0.9–1.0; anal lobes conical, strongly bent ventrally; c. 50 simple claws on posterior parapods.

Description

Adult male. Measurements and ratios in Table 1.

Coloration. Body with pale ground colour, brown scutal stripes, preepisternum, median anepisternum II, epimeron, postnotum, eyes and antenna.

Head. Antenna with 13 flagellomeres. Frontal tubercles present, small (6–13, 10 µm); temporal setae in 1 row, sometimes 2 rows anteriorly; palpomere 3 with c. 3 long sensilla clavata apically.

Wing. Subcosta and media bare, brachiolum with 3 setae, squama bare; cell m with c. 50 setae.

Legs. Pulvilli present, small, reaching base of claws. Fore tibia with small scale, c. 20 µm long spur; middle and hind tibial combs, respectively, 15–20, 18 and 20–25, 22 µm long; middle tarsomere Ta 1 with 0–2, 1 sensilla chaetica.

Hypopygium ( Fig. 8A, B ). Anal tergite with tergite bands separate, posteriorly directed, almost reaching crests of anal point; 3–6, 5 median tergite setae placed on an elevated hump anterior to anal point base; 10–12, 12 ventral apical setae. Anal point well developed, broadly triangular with broad base, high, slightly curved anal crests; moderately large knob between crests present; large microtrichia free area around base. Setiger of superior volsella roundish with 6–8, 7 dorsal and 2–3 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. Digitus long, apically pointed, medially curved, reaching beyond median margin of superior volsella. Median volsella comparatively long, thin, parallel sided, pointed, with medially directed setiform and spoonshaped lamellae, c. 15 spoon-shaped lamellae on distal 1/3; stem reaching well beyond superior volsella. Inferior volsella with small, dorsoapical swelling, otherwise quite straight, bearing numerous distal setae. Inner margin of gonocoxite with 3–4 strong setae.

Pupa. Coloration: pupal exuviae brownish with dark brown apodemes; cephalothorax, TVIII and anal lobe darker; large, rectangular, pigment-free area dorsally on thorax. Measurements in Table 2.

Cephalothorax ( Fig. 8C, D ). Cephalic tubercle present, relatively large, cone-shaped; pedicel sheath tubercle weak swelling. Thoracic horn fairly short with numerous comparatively short chaetae on distal 4/5; precorneals arranged in triangular pattern, the 2 anteriormost setae situated closer to each other than to the third, median precorneal shorter than other two; 1 median antepronotal, 2 lateral antepronotals (1 sensillum basiconicum); 2 pairs of dorsocentrals, equally strong, Dc 1 longer than Dc 2, Dc 3 and Dc 4. Small field of granulation dorsally on scutum. Prealar tubercle low mound; nose of wing sheath weakly developed.

Abdomen ( Fig. 8E, F ). TII extensively covered by shagreen except for one posteromedian and two lateral oval patches; pedes spurii B present on segment II; hook row somewhat longer than half tergite width. Spines of TIII in large, laterally curved patches in posterior half of tergite, points and shagreen extensively distributed lateral and anterior to spine patches, numerous points in between patches. Patches of TIV consisting of spinules in anterior, oval patches and points in broad longitudinal, lateral extensions, slightly broader posteriorly; fields of shagreen present laterally to longitudinal patches. Patches of TV similar to those of TIV in shape and size, consisting of points and spinules. Patches of TVI consisting of shagreen or small points, similar to patches on TIV and TV in shape and size. TVII and TVIII bare or with small, anterior, oval shagreen patches. Pleurae II–VI covered with 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, 2–3 L, 0–1 semitaeniate seta; segment IV with 5 D, 4 V, 2 L, 1 lateral taenia; segment V with 5 D, 4 V, 2 L, 1 lateral taenia; segment VI with 5 D, 4 V, 1–2 L, 2–3 lateral taeniae; segment VII with 5 D, 4 V, 0–2 L, 2–4 lateral taeniae; segment VIII with 1 dorsal taenia, 1 ventral taenia, 4–5 lateral taeniae; anal tergite with 1 dorsal taeniae. Two pairs of small sensorial setae medially on TII–VII; 1 pair of O-setae present anteriorly on sternites II–VII. Anal lobe lateral margins more strongly curved posteriorly; fringe with about 400–500 µm long taeniae in 1 row, usually a short taeniae-free area anterior on lobes, sometimes shorter than shown in Figure 8F . Posterolateral comb of segment VIII ( Fig. 8G ) comparatively broad, with 2–3 marginal teeth longer than rest.

Larva. Head capsule yellowish brown. Live individuals were not available for examination, but Thienemann (unpublished manuscript) reported them to be reddish. Total length 3.8–4.5 (2) mm long. Measurements and ratios in Table 3.

Head ( Fig. 8H–K ). AR about 1.8; antennal pedestal with median triangular, double, pointed spur; antenna with segments 1–2 well sclerotized, segments 3–5 pigmented, antennal seta placed at about 2/3 length of antennal segment 1; Lauterborn organs small, on pedestals; LOR about 3.0; SII plumose; chaetae pectinate, chaetulae and S3 simple; mentum with well developed lateral notches on median tooth; ventromental plates evenly curved with obvious striation along whole length; premandible with 2 robust teeth, inner tooth broader, well developed brush; mandible with pecten mandibularis slightly convex; postoccipital plate trapezoidal.

Body. Anterior prolegs with long, simple spines; hind prolegs with c. 50 simple hooks in two rows; L2 simple; anal segment with 4 conical anal tubules that are distinctly curved ventrally; supraanal seta 85–90 (3) µm long; procercus with one short and one long (c. 210 µm) dorsal seta, with 4 short and 4 long anal setae (n = 5).

Remarks

The Thienemann collection at ZSM contains numerous slides labelled ‘ Gowiniella bavarica ’, but not all of these are included in the present type material. We have excluded from the type series all unassociated females, misidentified males, and larvae that we were unable to identify with certainty.

Micropsectra bavarica is one of the few Micropsectra species we know as carrying shagreen on the pleura of the pupal abdomen. The other species recorded to have this feature are Micropsectra attenuata Reiss, 1969 , M. geminata Oliver & Dillon, 1994 , M. pharetrophora and M. klinki sp. nov. (see below).

In an unpublished manuscript, Thienemann reported all localities at which M. bavarica had been found to be hygropetric, and that the larvae lived in continuously wetted moss walls near mountain waterfalls and brooks. The species has been recorded from the European Alps, the Pyrenees and the Atlas mountains of northern Africa.

Figures

Figure 8. Micropsectra bavarica sp. nov. A, hypopygium. B, superior, median and inferior volsellae. C, pupal thorax. D, pupal frontal apotome. E, pupal abdominal segments II–VI, dorsal. F, pupal abdominal segments VIII–IX. G, posterolateral combs of pupal segment VIII. H, larval antenna. I, larval premandible. J, postoccipital plate of larval head capsule. K, larval mentum, ventomental plates and setae submenti.