Micropsectra klinki, 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 : 193-196

MICROPSECTRA KLINKI SP. NOV.

Micropsectra Sterkselse Aa ( Klink, 1982; Klink & Moller Pillot, 2003).

Micropsectra ‘Sterkselse Aa’ Klink ( Langton, 1991: 372).

Micropsectra sterkselse-aa ( Langton & Visser, 2003). Holotype P£ ( ZMBN no. 410), the Netherlands, Hulshorst, Hierdense Beek, mp. 2a waterval, 10.xii.1981, A. Klink. 5 paratypes: 4££ ( ZMBN) as holotype except collected by F. Repko, 13.xii.1978; 1£ ( ZMUH) Finland, Oulun Laani , Rühimäki, 26.ix.1981, J. Tuiskunen.

Etymology

The species is named after our colleague, Alexander Klink, who first described the features of this species, and collected the holotype.

Diagnostic characters

Micropsectra klinki can be separated from other species in the atrofasciata group by the following combination of characters: adult male with frontal tubercles minute; AR c. 1.2; pulvilli absent; anal point well developed, narrow, apically very thin and pointed, knob between crests absent; microtrichia between crests present; superior volsella with field of microtrichia on stem; setiger large, roundish, with several long microtrichia in small field ventrally, anterior to base of digitus, no wrinkles ventroapically on setiger; digitus long, finger-like, occasionally reaching beyond median margin of superior volsella; median volsella moderately long, tip not reaching past posterior margin of superior volsella, apically pointed, with about 25 dorsomedially directed spoon-shaped lamellae on distal third, setiform lamellae along whole length medially. Pupa with cephalic tubercles moderately developed; thoracic horn relatively long with comparatively short, sparse chaetae on at distal 2/3; prealar tubercle absent; thin dorsal row of granulation along scutal suture; large rectangular, dorsal, unpigmented area in middle of thorax; tergite III with spines in posterior, laterally curved patches; points and short spinules in long patches on tergites IV–V; shagreen in patches on tergite VI; patches on tergite VI of smaller size than patches on tergites IV–V; numerous microtrichia present between spine patches on tergite III; dorsolateral comb of segment VII narrow with 4 separated, marginal teeth of which 3 are larger than the remaining. Larva (see Klink, 1982; Klink & Moller Pillot, 2003) with small, pointed triangular spur on antennal pedestal; antennal segment 1 c. 260–360 µm long; seta SII pectinate; clypeal seta S3 simple; supra-anal seta fine, barely visible under 80× magnification.

Description

Adult male. Measurements and ratios in Table 1.

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

Head. Antenna with 13 flagellomeres. Frontal tubercles present, small (7–8 µm); temporal setae in one row; palpomere three with 4–5 sensilla clavata in bundle.

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

Legs. Pulvilli absent. Fore tibia with small scale, small spur 18–20 µm long; middle and hind tibial combs 18–20 µm and 24–26 µm long, respectively; middle tarsomere Ta 1 with 3–4 sensilla chaetica.

Hypopygium ( Fig. 11A, B ). Anal tergite with tergite bands separate, posteriorly directed, not reaching crests of anal point; 5–6 median tergite setae placed on an elevated hump anterior to anal point base; 16–21, 17 ventral apical setae. Anal point triangular, with high slightly curved anal crests, apex long, thin, pointed; knob between crests absent; microtrichia between crests present; large microtrichia free area around base. Setiger of superior volsella large, roundish, with 7–8 dorsal and 2 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 finger-like, long, sometimes reaching past median margin of superior volsella. Median volsella comparatively short, slightly pointed, otherwise parallel sided, with medially directed setiform and spoon-shaped lamellae, c. 25 spoon-shaped lamellae on distal 1/3; stem never reaching beyond superior volsella. Inferior volsella slightly club-shaped with small median and dorsoapical swelling, 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 slightly darker; large, rectangular pigment-free area dorsally in middle of thorax. Measurements in Table 2.

Cephalothorax ( Fig.11C, D ). Cephalic tubercle present, low cone; pedicel sheath tubercle absent. Thoracic horn fairly long with numerous comparatively short chaetae on distal 2/3; 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, anterior pair shorter and weaker than posterior pair, setae of anterior pair equally strong, Dc 3 broken off. Some granulation present along median suture line of thorax. Prealar tubercle absent; nose of wing sheath weakly developed.

Abdomen ( Fig. 11E, F ). TII almost covered by shagreen except for one posteromedian oval patch; pedes spurii B on TII obvious; 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, numerous points between patches. Patches of TIV consisting of spinules and points in anterior, oval patches and in longitudinal, lateral extensions that are slightly laterally curved posteriorly; shagreen present laterally to longitudinal patches. Patches of TV similar to those of TIV in shape and construction, somewhat shorter. Patches of TVI consisting only of shagreen, shorter than patches on TIV–V. TVII usually bare; TVIII with small anterolateral patches of shagreen. Pleurae I and II with fine 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)L, 1–2 lateral taeniae; 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 taeniae. Two pairs of small sensorial setae medially on TII–VII; 1 pair of O-setae present anteriorly on sternites II–VII. Anal lobe with more strongly curved lateral margins posteriorly, fringe with about 540 µm long taeniae in 1 row. Posterolateral comb of segment VIII narrow, with 3 marginal teeth longer than rest.

Larva ( Klink, 1982; Klink & Moller Pillot, 2003). Head capsule yellowish. Live individuals were not available for examination. Total length c. 8 mm. Measurements and ratios in Table 3.

Head. Antennal pedestal with short, triangular, pointed spur, distance between antennal pedestals at most 38 µm ( Klink, 1982); antenna with segment 1 well sclerotized, antennal seta placed at about 1/2–2/3 length of antennal segment 1; antennal segment 2 cylindrical, longer than segments 3–5. Lauterborn organs small on very long pedestals ( Klink & Moller Pillot, 2003); SII pectinate; S3 simple; mentum with notches on median tooth; ventromental plates evenly curved with obvious striation along whole length, wider than width of mentum; premandible with 2 robust teeth, inner tooth broader, well developed brush; mandible with pecten mandibularis; seta subdentalis extending well beyond apical mandibular teeth.

Body. Anterior prolegs with long, simple spines; hind prolegs with c. 50 simple hooks in two rows; L2 simple, long; supraanal seta fine, barely visible under 80× magnification.

Remarks

Micropsectra klinki was first described as ‘ Micropsectra Sterkselse Aa ’ by Klink (1982: 42), but since the author explicitly stated that he was not proposing a scientific species name, no such name was made available (ICZN, 1999: article 8.3). The subsequent descriptions of the pupal exuviae by Langton (1991) and Langton & Visser (2003), and of the larva by Klink & Moller Pillot (2003), have not established an available name either. Langton (1991) merely cited Klink’s unavailable name (in quotation marks), and the two latter works neither constitute nomenclaturally valid publications (ICZN, 1999: article 8.6), nor do they designate a holotype or explicitly state that the species is new to science, as required after 1999 (ICZN, 1999: articles 16.1 and 16.2, respectively). We therefore hereby describe the species as new to science and designate the appropriate types to ensure future stability of the species.

Unfortunately, only a few male specimens, one pupal exuvia and no larvae were available for examination. The larval description therefore is solely based on the information given by Klink (1982) and Klink & Moller Pillot (2003). Klink (1982) erroneously used the term ring organ for the seta present on larval antennal segment 1.

Micropsectra klinki is very similar to M. logani in the adult male stage, but can be separated by having a shorter median volsella the stem of which never reaches past the posterior margin of the superior volsella. In The Netherlands, M. klinki has been collected predominantly from the middle reaches of streams with fluctuating discharge; larvae are often found in the moss Fontinalis antipyretica at strong currents ( Klink, 1982).

Figures

Figure 11. Micropsectra klinki 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.