Micropsectra atrofasciata, (KIEFFER)

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 : 182-187

MICROPSECTRA ATROFASCIATA (KIEFFER)

Tanytarsus atrofasciatus Kieffer, 1911: 59 . Lectotype £ by present designation (RBINS) Germany, Westphalia , Wiesengraben north of Münster, 14.iii.1910, A. Thienemann. 1 paralectotype Pex (ZSM) as lectotype [both examined].

Syntanytarsus (Eutanytarsus) suecicus Kieffer in Thienemann & Kieffer (1916): 501. Lectotype £ by present designation (RBINS) Sweden, Hälsingborg , Pålsjö, spring at beach, 6.viii.1912, A. Thienemann; 7 paralectotypes: 3££ & 4 male Pex as lectotype, except 2 Pex in ZSM [all examined]. syn. nov.

Tanytarsus sexannulatus Goetghebuer, 1921: 126 . Syntype £ (RBINS) Belgium, Schelderode, 25.iv.1913, M.Goetghebuer [examined]. Synonymy by Goetghebuer (1928: 158).

Tanytarsus bidentatus Goetghebuer, 1921: 172 . Lectotype £ by present designation (RBINS) Belgium, Virton , light trap, 31.vii.1920, M. Bray. 2 paralectotypes: 1£, 1$ as lectotype [all examined]. syn. nov.

Micropsectra subnitens Goetghebuer, 1928: 115 . Syntype £ (RBINS) Belgium, Hockai , 6.vi.1924, M.Goetghebuer [examined]. syn. nov.

Micropsectra pallida Goetghebuer, 1949: 7 . Holotype £ (RBINS) Austria, Murufer bei Gorz, 1948, H. Franz [examined]. syn. nov.

Micropsectra miki Marcuzzi, 1950: 274 . Holotype £ (NMW Präparat 374) Italy, Friuli, Venezia Giulia, Gorizia, 20.IV. 1864, Mik [examined]. syn. nov.

Micropsectra shouharasima Sasa, 1989: 35 . Holotype £ (NSMT, Sasa collection No. A 154: 19) Japan, Toyama Prefecture, Shou River , St. 4, 1.xii.1988; 1 paratype £ (A152: 57) as holotype, except St. 1, 25.viii.1988 [both examined]. syn. nov.

Micropsectra jokaquarta Sasa & Ogata, 1999: 93 . Holotype £ & paratype $ (NSMT, Sasa collection no. 352: 68–69) Japan, Kurobe , Kurobe Joka centre, 2.II. 1998, M. Sasa & K. Ogata [examined]. syn. nov.

Additional material examined

Belgium ( RBINS): 2££ Hockai, 6.vi.1924, M. Goetghebuer; 1£ hypopygium no locality or date; 2££ Hasselt , ix.1932, Koch . Germany ( ZSM): 1£ Bavaria, Garmisch- Partenkirchen, Murnauer Moos , 22.viii.1978, R. Kühbandner; 4££ Hessen, Fulda, Wasserkuppe , 10.viii.1953, 16.viii.1953, 19.viii.1953, 1.x.1953, E. J. Fittkau; 4 P££ Hessen, Fulda, Kohlhausen, 2.viii.1967 & 19.ix.1967, J. Lehmann; 1 P£ as previous except at Hutzdorf , 19.ix.1967; 1 P£ & 1£ as previous except near Lüdermünd , 14.vii.1967 & 13.iv.1967; 2££ as previous except near Kassel, 9.iv.1967 & 19.vi.1967; 1 P £ Hessen, Fulda – EAW, 30.x.1952, E. J. Fittkau; 1£ as previous except Sandlofs Brücke, 24.x.1952; 1 P£ as previous except bridge at Kohlhaus, 7.vii.1952; 1£ Schleswig- Holstein, Lower Schierenseebach , 22.iv.1985, U. Holm; 1 £ Schleswig-Holstein, Rendensburg-Eckernförde, Fuhlenau , 30.viii.1982, K. Mikowski; 1 £ Saarland, Wiebelskirchen, Blies , 9.vii.1962, F. Reiss; 1 P £ Bavaria, München, Isarkanal, Grosshesseloher Brücke , 29.vi.1981; 1 £ Nordrhein-Westfalen, Brackwede , 17.iii.1915, A. Thienemann; 1 P £ Schleswig-Holstein, Plön, Stream at Vierersee , 18.iv.1967, F. Reiss . France ( ZSM) : 1£ Pyrenees, Barèges , 1300 m a.s.l., 1948, Bertrand. 1£ ( ZSM) Morocco, 17 km S of Tizi and Test, 28.II. 1966, F. Ringe; 1£ as previous except 15 km W of Ljoukak , 1.iii.1966. 2££ ( ZSM) Algerie, Alger, 31.iii.1957, Clastrier. 1 £ Israel, Tel-el-kadi, 31.xii.1966, J. Kugler. 16L, 2 P, 2 Pex ( ZSM) Sweden, Hälsingborg, Pålsjö , spring at beach, 6.viii.1912, A. Thienemann. 1 LP$ ( ZMBN) , Norway, Hordaland, Ulvik, Finse , at research station, 24.viii.1999, T.Ekrem; 4££ ( VM) , Norway, Sør Trøndelag, Oppdal, Kongsvoll , Blesbekken , emergence trap, 14.viii.1979, 31.vii.1979, 20.viii.1979, J. O. Solem; 4££ ( VM) as previous, except MT, 1350 m a.s.l., 15.viii.1982 & 28. viii.1982; 1£ ( VM) , Norway, Oppland, Dovre, Atnaelv, Dørålseter , MT, 26.vii.1986, K. Aagaard & O. Hanssen; 3££ as previous, except Hedmark, Storelvdal, Atnaelv, Solbakken , 17.vi.1986 & 24.vi.1986 . England ( PHL): 9 P(££) & 2 P($$), Bath and NE Somerset, River Chew, Stanton Drew , 25.iv.1973, 9.v.1973, 3.vii.1973, P. H. Langton; 1 P £, Worcestershire, Lulsley , stream in nature reserve, 28.iii.1989; 1 P(£) & 2 LP££ , Suffolk, West Stowe, stream south of River Lark , 22.II. 1982 & 25.II. 1981, P. H. Langton; 1 LP £ Suffolk, Glemham House Lake , 19.iv.1975, P. H. Langton; 3 L , Hertfordshire, River Ver, Chegus Inn , 25.iii.1996, P. H. Langton; 1 L , Hertfordshire, River Ver , Luton Lane , iv.1996, P. H. Langton; 1 LP $, Cambridgeshire, March, Barker’s Lane ditch, 4.vii.1984, P. H. Langton. 2 P(££) ( PHL) Northern Ireland, Coleraine, River Bann, Mountsandel , 18.iii.1999 & 27.I. 2000, P. H. Langton. 1 P(£) ( PHL) France, eastern Pyrenees, Vinça, Ruisseau , 19.xi.1980, P. H. Langton; 1 P(£) ( PHL) France, eastern Pyrenees, Massane river , 25.iii.1995, T. Moubayed . Poland ( WG): 2££, Kashubia, Mirachowo , netting on stream, 16.iv.1998, W. Gilka .

Diagnostic characters

Micropsectra atrofasciata can be separated from other species in the atrofasciata group by the following combination of characters: Adult male with AR c. 1.0; frontal tubercles minute to very small; pulvilli absent; anal point well developed, broadly triangular, apically blunt or concave; small knob between anal crests; superior volsella with small to large field of microtrichia on stem, setiger large, roundish, several long microtrichia ventrally on setiger around base of digitus, slight granulation ventroapically on setiger; digitus short to medium long, never reaching median margin of superior volsella; median volsella long, thin, broadest at base, reaching well beyond superior volsella, apically pointed, with about 25 dorsomedially directed, spoon-shaped lamellae on distal 1/3, setiform lamellae along whole length dorsally and medially. Pupa with small, cone-shaped cephalic tubercles; thoracic horn with comparatively short chaetae on distal 1/2–3/4; prealar tubercle well developed, rounded; small dorsal field of granulation on mid thorax; large, rectangular unpigmented area dorsally on posterior half of thorax; strong spines in patches on tergite III and on tergite IV (in the longitudinal, lateral extensions); spinules and points in patches on tergite V; shagreen in patches on tergite VI; patches on tergite VI of smaller size than patches on tergites IV–VI; microtrichia usually absent between spine patches on tergite III; dorsolateral comb of segment VII narrow with 3–5 separate, marginal teeth of which one is larger than the remaining. Larva with small, triangular spur on antennal pedestal; Antennal segment 1 c. 180–220 µm long; comparatively high AR (c. 2.3); LOR c. 3.8; labral seta SII and some chaetae plumose; clypeal seta S3 simple; MVR about 0.8.

Description

Adult male. Measurements and ratios in Table 1.

Coloration. Body with light greenish ground colour with brown eyes, pedicels, vittae on mesonotum, postnotum, median anepisternum II, preepisternum and epimeron II; scutellum and halteres pale; legs brownish.

Head ( Fig. 3B ). Antenna with 13 flagellomeres. Frontal tubercles present as minute dots or small (c. 6 µm); temporal setae in 1 row; palpomere three with 2–5 sensilla clavata in subapical pit.

Wing ( Fig. 3A ). Subcosta and media bare, brachiolum with 2–3 setae, squama bare.

Legs ( Fig. 3C ). Pulvilli absent. Fore tibia with small scale, 18–28, 22 µm long spur; mid and hind tibial combs, respectively, 18 and 20 µm long; mid ta 1 with 4–8, 6 sensilla chaetica.

Hypopygium ( Fig. 7A–C ). Anal tergite with tergite bands separate, posteriorly directed, reaching crests of anal point; 6–10, 8 median tergite setae placed on an elevated hump anterior to anal point base; 11–15, 13 ventral apical setae. Anal point broadly triangular, with high slightly curved anal crests, apex blunt, often concave; small knob between crests present; large microtrichia free area around base. Setiger of superior volsella large, roundish with 7–12, 10 dorsal and 4–5, 4 median setae on setiger, 1 strong seta on stem; small to large field of dorsal microtrichia on stem and several long microtrichia ventrally on setiger, around base of digitus. Digitus short or medium long, digitiform, never reaching median margin of superior volsella. Median volsella comparatively long, thin, pointed, broader at base, with medially and dorsally directed setiform and spoon-shaped lamellae, spoonshaped lamellae on distal 1/3; stem reaching well 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. Coloration: pupal exuviae brownish with dark brown apodemes; cephalothorax, TVIII and anal lobe darker; large, rectangular pigment-free area dorsally in posterior half of thorax. Measurements in Table 2.

Cephalothorax ( Fig. 7D, E ). Cephalic tubercle present, small, cone-shaped; pedicel sheath tubercle very weak. Thoracic horn fairly long with numerous comparatively short chaetae on distal 1/2–3/4; 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 each pair equally strong. Some granulation present along median suture line and in small dorsal field on mid thorax. Prealar tubercle present, large, roundish; nose of wing sheath weak to well developed.

Abdomen ( Fig. 7F, G ). TII almost covered by shagreen except for one posteromedian oval patch; pedes spurii B on segment II obvious; hook row about 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, only rarely a few points between patches. Patches of TIV consisting of spinules in anterior, oval patches with spines in longitudinal, lateral extensions which are slightly laterally curved posteriorly; some shagreen present lateral to longitudinal patches, and sometimes between anterior spinule patches. Patches of TV similar to those of TIV in shape, somewhat shorter, consisting only of points. Patches of TVI consisting only of shagreen, similar to patches on TIV and TV in shape, but without anterolateral extensions and distinctly shorter. TVII and TVIII usually bare. 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, 1–3 L, 0–2 lateral taenia; 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 taenia. Two pairs of small sensorial setae medially on TII–VII; 1 pair of Osetae present anteriorly on sternites II–VII. Anal lobe with evenly convex lateral margins, fringe with about 400–500 µm long taeniae in 1 row. Posterolateral comb of segment VIII ( Fig. 7H ) narrow, usually with one marginal tooth longer than rest.

Larva. Head capsule well sclerotized and dark brown. Live individuals were not available for examination, but Thienemann & Kieffer (1916) reported them to be pink. Total length 4.6–5.1, 4.8 mm. Measurements and ratios in Table 3.

Head ( Fig. 7I–L ). AR about 2.0; antennal pedestal with short triangular 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 3.8; SII and some chaetae plumose; some chaetae, chaetulae and S3 all simple; mentum with well developed lateral notches on somewhat pale 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 well developed, triangular.

Body. Anterior prolegs with long, simple spines; hind prolegs with c. 50 simple hooks in two rows; L2 simple; anal segment with 4 anal tubules; supraanal seta c. 120 µm long; procercus with 1 short and 1 long (c. 200 µm) dorsal seta, with 4 short and 4 long anal setae (n = 5).

Remarks

The specimen marked ‘ Micropsectra atrofasciata ’ and ‘Type de Kieffer’ in RBINS fits the original description. Although there is no locality label on the specimen to confirm its type status, is conspecific with a pupal exuviae from the original sample ( ZSM), and is hereby designated lectotype to stabilize nomenclature. From Thienemann’s notes present in ZSM it is clear that the original sample from which Micropsectra atrofasciata was reared contained at least two Tanytarsini species: ‘ Tanytarsus atrofasciatus’ and ‘ Tanytarsus trivialis ’. The latter species is currently regarded as a junior synonym of Micropsectra apposita (Walker) , although Kieffer’s (1911) original description of T. trivialis does not completely match M. apposita as understood today. The synonymy was proposed by Säwedal (1976) who also designated a lectotype for T. trivialis .

There is only one slide present in ZSM (no alcohol material) that carries a label with ‘Jägerhäuschen Tanytarsus b’, which in Thienemann’s notes is the designation for the type sample of both T. atrofasciatus and T. trivialis . The slide holds three pupal exuviae, of which one is conspecific with individually reared material, and with the type-labelled male of M. atrofasciata in Brussels ( RBINS). This pupal exuviae is hereby designated paralectotype. The other two specimens belong to T. pallidicornis Walker , and are thus not conspecific with the lectotype of T. trivialis . It is beyond the scope of this study to find the true identity of T. trivialis , since the species obviously is taxonomically different from the atrofasciata species group, but it is clear that either Thienemann’s original sample included three different tanytarsine species or the specimens labelled ‘ Micropsectra trivialis K.’ and ‘Type de Kieffer’ in RBINS are not from the original sample.

Micropsectra suecica is listed as a nomen dubium in the Palaearctic catalogue ( Ashe & Cranston, 1990), but examination of the specimen labelled ‘ Type de Kieffer’ in RBINS and the presumable syntypes in ZSM shows synonymy with M. atrofasciata . Although there are no locality or date labels on the RBINS specimens, they fit the original description and are conspecific with pupal exuviae from the original sample present in ZSM. Thienemann’s notes reveal that the adults and pupal exuviae were reared from larvae collected at a single locality. RBINS and ZSM hold six pupal exuviae collected by Thienemann from this locality, but we regard only the four male exuviae as paralectotypes, since no females were included in the original description. One male specimen present in RBINS is designated lectotype to stabilize nomenclature. The Thienemann collection ( ZSM) also holds larvae and pupae from the type locality. These are regarded as tentatively associated, and are included in the above description .

The labelled types and original descriptions of Tanytarsus sexannulatus , Micropsectra subnitens and M. pallida ( Goetghebuer, 1921, 1928, 1949) and those of M. shouharasima and M. jokaquarta ( Sasa, 1989; Sasa & Ogata, 1999) have been examined and found to be conspecific with M. atrofasciata .

Micropsectra bidentata ( Goetghebuer, 1921: 172) is here regarded as a new junior synonym of M. atrofasciata . We examined a specimen in RBINS labelled ‘Type M. Goetghebuer’ and ‘ M. bidentata ’, but this cannot be an original type since its label records a different locality (‘Bullange’) and a collecting date (‘ 21.IX.1923 ’) by ‘G. Severin’ after the original publication of Tanytarsus bidentatus Goetghebuer, 1921 . Moreover, the original description (with figures) presents a male hypopygium with a short anal point and digitus, and does not fit the specimen from Bullange (see M. pallidula described below). The only specimens present in RBINS which match the date and locality given in the original description (July, Virton) are two males and one female on one pin (B. Goddeeris, pers. comm.). Examination of these specimens labelled ‘Virton, 31.VII.1920 ’ revealed that they fit the original description of T. bidentatus and that they are conspecific with M. atrofasciata . One of the males is hereby selected lectotype to stabilize nomenclature. The lectotype and the two paralectotypes have been mounted in Euparal on separate microscope slides.

No specimen of M. miki other than the holotype was available for examination and there is to our knowledge no other record of this species. The type has lost all but the abdomen and one hind femur and tibia, but mensural data and the coloration given in the original description ( Marcuzzi, 1950) are within the ranges typical for M. atrofasciata . The modern standard wing length for the holotype of M. miki most likely is at least 0.5 mm shorter than the wing length reported in the original description, since that difference was observed on the types of both M. andalusiaca and M. zernyi (described in the same paper), and the wing of M. miki was described as 0.75 mm longer than those of the other species.

Tanytarsus bipectinatus Goetghebuer 1933: 211 was listed by Reiss & Fittkau (1971: 82) as a synonym of M. atrofasciata , based on examination of a specimen considered as the ‘Holotypus’. However, Goetghebuer’s (1933) publication reported a series of specimens, not a holotype, and the description clearly fits the diagnosis of Tanytarsus . We have examined two specimens in RBINS marked ‘Type Goetghebuer’ and ‘Paratype’ bearing the type locality label (‘Hasselt, IX.1932, leg. Debauche et Koch’); both are conspecific with M. atrofasciata . It is likely that Reiss & Fittkau (1971) saw one of these. However, Goetghebuer’s (1933) description obviously was based on one or more different specimens. Unfortunately, it is insufficient for identification of the Tanytarsus species involved. Therefore, we hereby dissolve the synonymy by Reiss & Fittkau (1971) and consider T. bipectinatus as a nomen dubium in Tanytarsus .

Micropsectra atrofasciata has been recorded from springs, ditches, streams and lakes throughout Europe. There are also records from the eastern Palaearctic, Near East and North Africa ( Saether & Spies, 2004).

Figures

Figure 3. Morphology of species in the atrofasciata species group. A, wing (Micropsectra atrofasciata). B, head (M. atrofasciata). C, fore, mid and hind tibiae (M. atrofasciata). D, thorax (M. logani).

Figure 7. Micropsectra atrofasciata. A, hypopygium. B, superior, median and inferior volsellae. C, median volsella. D, pupal thorax. E, pupal frontal apotome. F, pupal abdominal segments II–VI, dorsal. G, pupal abdominal segments VIII–IX. H, posterolateral combs of pupal segment VIII. I, larval antenna. J, larval mandible. K, larval mentum, ventromental plates and setae submenti. L, postoccipital plate of larval head capsule.