Stempellinella ciliaris (Goetghebuer)

Ekrem, Torbjørn, 2007, A taxonomic revision of the genus Stempellinella (Diptera: Chironomidae), Journal of Natural History 41 (21 - 24), pp. 1367-1465 : 1395-1401

Stempellinella ciliaris (Goetghebuer)

Stempellina ciliaris Goetghebuer 1944, p 35 . Lectotype „ ( RBINS) Austria, Lunz , Meiergraben, 8 September 1943, A. Thienemann . Paralectotype ♀ as lectotype [both examined]. Lectotype here designated.

Stempellinella ciliaris (Goetghebuer) . Stur et al. (2005) parasitism, biology.

Stempellinella sp. 1 . Ekrem (2005) pupal behaviour.

Zavrelia inopinata Botnariuc and Cindea-Cure 1954, p 1 . Syntypes: 28 L, Romania, Bistrit , a, Izvorul Muntelui, 14 April 1951; 2 L, Romania, Mt. Potoci, 17 May 1951, leg. Employees of the Fishery Research Institute [material not located]. Syn. n.

Additional material examined

Austria: 1 „, 6 Pex ( ZSM) as lectotype; 1 Pex ( SM), Oberösterreich, Attersee , boat harbour, 7 August 1996, S. Michiels; 1 Pex (VM) as previous except Alexenauer Bach 0.6 km at Attersee, 4 August 1997; 1 Pex ( SM), Salzkammergut, Klausenbach, spring brook, 600 m a.s.l., S. Michiels, 8 August 1997; 1 Pex as previous except Klausenbach near Attersee; 1 Pex (VM) as previous except Moosbach at Schwarzensee, 750 m a.s.l. France: 1 Pex ( ZSM), Alps , Le Cians, 400 m a.s.l., 11 September 1996, drift, W. Schacht; 2 P(„), 1 „ ( PHL), Corsica, Corte´ , Gorges de la Restonica, 5 July 1995, H. Laville. Germany ( ZSM): 1 „, Bavaria, Mindelsee ( Bodenseee ), 11 May 1963, F. Reiss; 3 „„ , Bavaria, Fürstenfeldbruck, Schöngeising, Kellerbach , 24 July 1992, 1–6 September 1991, W. Schacht; 1 „, Bavaria, Bodensee, Überlingen, Deisendorfer Weiher, 22 May 1966, F. Reiss; 1 „ , Bavaria, Allgäu, Füssen, Weissensee , 29 June to 2 July 1965, F. Reiss; 2 Pex , Bavaria, Puppling; 1 „, Bavaria, Berchtesgaden National Park, Herrenroint , spring # 308, 18 November 1996, I. Schrankel; 1 „ as previous except spring brook, 6 September 1996, I. Schrankel; 1 „, 2 Pex , Bavaria, Königsee , drift, 11 September 1986, R . Gerstmeier . Luxembourg: 1 „ (VM, To 159), Gutland , SW Kopstal, rheocrene spring # qu25, netting, 265 m a.s.l., 8 July 2003, T . Ekrem ; 2 LP („), 3 LP (♀), 2 L as previous except benthos sample 6 May 2005, emergence 18 May 2005, 21 May 2005, 31 May 2005; 19 „„ ( MGDL) as previous except emergence trap E7, 4 May 1999, 18 May 1999, 1 June 1999, 15 June 1999, 29 June 1999, 13 July 1999, 27 July 1999, 10 August 1999, I. Schrankel; 1 LP („) (VM, To 169) Schlennerbach , emergence, 12 June 2005, P. Martin .

Diagnostic characters

Stempellinella ciliaris can be separated from other species in Stempellinella by the following combination of characters. Adult male with AR ca 0.80; superior volsella with medially pointed apex and two median setae; anal point long and slightly triangular with long, strong crests which end far distal on the anal point, several long spinulae between crests; lamellae of median volsella almost reaching apex of inferior volsellae. Adult female with large seminal capsules, diameter as large or larger than length of notum excluding rami and considerably larger than length of cercus; small vaginal floor, covering ca one-quarter of vaginal opening ventrally; gonocoxapodeme strongly curved. Pupa with low, broad conical cephalic tubercles; chaetae distributed evenly on distal two-thirds of thoracic horn; shagreen on pleura IV; anterior patches or transverse band of points on tergite VII. Larva with moderate (ca 20 Mm long), digitiform spur on antennal pedestal; antennal segment 3 inserted subapically on segment 2; antennal blade reaching beyond apex of distal Lauterborn organ; AR 0.87–0.97, 0.91; AAR about 1.20; S3 split in three branches; distal Lauterborn organ on longer pedicel.

Description

Adult male (n 5 5, unless otherwise stated). Total length 1.5–1.7, 1.6 mm; wing length 1.14– 1.27, 1.21 mm.

Colour: yellow-brown ground colour with light brown scutal stripes, postnotum and preepisternum; abdomen paler than thorax; antennal pedicels dark brown dorsally; eyes brown, darker ventrally.

Head ( Figure 9A, B ): eyes without dorsomedian elongation; frontal tubercle large, conical, 9–18, 13 Mm long; antenna with 13 flagellomeres of which only 10 are easily discernible; AR (on 10 flagellomeres) 0.75–0.84, 0.80; lengths of palpomeres (in Mm): 18– 24, 21; 21–27, 24; 60–72, 65; 84–93, 88; 114–132, 124 (n 54). Clypeus about 45–50 Mm long with 8–12, 10 setae; tentorium ca 90 Mm long, 18 Mm wide; three inner verticals, three outer verticals, three postorbitals.

Thorax: scutal tubercle absent; acrostichals 11–14, 13; dorsocentrals 5–7, 6; humerals 0– 4, 1; prealars 1; scutellars 6; halterals 5–6.

Wing ( Figure 9C ): cuneiform, 2.9–3.1, 3.0 times longer than broad; VR 1.56–1.67, 1.62; wing setation as in Figure 9C .

Legs ( Figure 9D ): fore tibia with 14 Mm long spur; mid and hind tibiae with wellseparated, 12–14 Mm long tibial combs, one mid tibial comb with 30 Mm long spur, one hind tibial comb with 34 Mm long spur; mid tarsus 1 without sensilla chaetica; pulvilli absent. Lengths and ratios of leg segments in Table III.

Hypopygium ( Figure 9E, F ): anal tergite 96–114, 102 Mm long with transverse anal tergite band; four to seven, five strong median setae at some distance from anal point base and usually one or two small median setae close to anal point base, one lateral seta, 16–20, 19 apical setae; anal point 42–50, 47, 33 Mm long, basally 12 Mm broad with long, well-developed crests which end close to anal point apex; 9–14, 12 long spinulae between anal crests; microtrichia-free area on each side of anal point base. Gonocoxite 87–99, 91 Mm long; gonostylus 60–75, 63 Mm long; HR 1.32–1.50, 1.45. Superior volsella ( Figure 9F ) with strongly tapered, medially directed apex, with four or five dorsal and two median, long setae on setiger, superior volsella otherwise bare; digitus absent; median volsella 30–36, 35 Mm long, straight, posteromedially directed, stem simple with numerous simple 30–36, 32 Mm long lamellae which almost reach apex of inferior volsella; inferior volsella ca 54–69, 61 Mm long, slightly club-shaped, with several distal setae, dorsal surface without microtrichia, obvious microtrichose wart basally on inferior volsella.

Adult female (n 5 3, unless otherwise stated). Total length 1.3 (n 51) mm; wing length 0.84 (n 51) mm.

Colour: as male, except slightly paler.

Head: as male, except cephalic tubercles shorter, ca 6 Mm long; antenna ( Figure 9G ) with five flagellomeres, ultimate flagellomere 45–54, 51 Mm long, AR 0.21–0.33, 0.27; lengths of palpomeres (n 52, in Mm): 21; 21–24; 45–54; 66–72; 105–120. Clypeus with 8–11, 9 setae.

Thorax: acrostichals 11–17, 13; dorsocentrals 5; humerals 1–4, 2; prealars 1; scutellars 6; halterals 6.

Wing (n 51): as male, except 3.2 times longer than broad, VR 1.55.

Legs: as male, except two sensilla chaetica distally on mid tarsomere 1.

Genitalia ( Figure 9H ): tergite IX slightly triangular, about 30–35 Mm long; sternite VIII with 18–26, 22 setae, of which none or one are placed on vaginal floor; vaginal floor small, covering ca one-quarter of vaginal opening ventrally; gonapophysis VIII single lobe with long posteromedially directed microtrichia; gonocoxapodeme strongly curved; coxosternapodeme well developed with obvious anterior and posterior lobes. Notum including rami 102–114, 108 Mm long, notum alone ca 60 Mm long. Seminal capsules ovoid, large, diameter 60–66, 63 Mm with 165–200, 182 Mm long spermathecal ducts. Postgenital plate subtriangular. Cercus 30–39, 34 Mm long.

Pupa (n 5 5, unless otherwise stated). Total length 1.7–2.1, 1.8 mm; abdomen 1.2–1.6, 1.4 mm long. Colour of pupal exuviae pale brown with darker lateral margins on abdominal segments VII – VIII and anal lobe.

Cephalothorax ( Figure 10A, B ): cephalic tubercles moderately developed, low, broad conical, 15–25, 20 Mm long ( Figure 10A ); frontal setae taeniate, 75–120, 100 (n 52) Mm long; pedicel sheath tubercle absent. Thoracic horn 225–315, 261 Mm long, 15–24, 20 Mm wide with 6 Mm long chaetae evenly distributed on distal two-thirds; precorneals taeniate, ca 100–120 Mm long, arranged in a slight triangle on obvious mound, anterior two placed closer together; median antepronotal taeniate, two lateral antepronotals: one taeniate, one sensillum basiconicum; two pairs of fine dorsocentrals, all about 25–30 Mm long. Area of fine sculpturing anteriorly on thorax ( Figure 10B ), a few stronger granules present along median suture line. Prealar tubercle well developed, wide; nose of wing sheath strong.

Abdomen ( Figure 10C ): TII with triangular posteriomedian point patch posteriorly to seta D1; hook row 50–66, 59 Mm wide with 23–31, 27 hooks. TIII – VI with p -shaped point patches; TVII with anterior patches or transverse band of points; TVII –IX with anterolateral patches of shagreen. Segment II with pedes spurii B; segment IV with pedes spurii A. Segment II with 2 D, 2 V, 3 L setae; segment III with 3 D, 2 V, 2 L and 1 semitaeniate L setae; segment IV with 3 D, 3 V, 2 L, 1 semi-taeniate L setae; segment V with 3 D, 3 V, 3 taeniate L setae; segment VI – VII with 3 D, 3 V, 4 taeniate L setae, segment VIII with 1 D, 1 semi-taeniate V, 3 taeniate L setae; segment IX with 1 D seta on anal lobe, 13– 16, 14 taeniate setae in anal fringe. One pair of O-setae present anteriorly on tergites II – VII and anterolaterally on sternites II – VIII. Pleura IV with shagreen. Posterolateral spur on segment VIII well developed.

Larva (n 5 5, unless otherwise stated). Total length ca 1.4–1.8 (n 52) mm, case ca 3 mm. Head capsule brown, somewhat darker postoccipital rim and teeth on mandible and mentum. Live individuals with yellow body colour.

Head ( Figure 10D–I ): AR 0.87–0.97, 0.91; antennal pedestal 75–80, 78 Mm long with well-developed, 18–24, 20 Mm digitiform spur; antenna ( Figure 10D ) with all segments well sclerotized, segment lengths (in Mm): 60–66, 64; 42–45, 44; 10–12, 11; 9–12, 10; 5; segment 3 inserted subapically on segment 2; AAR 1.14–1.33, 1.21. Antennal seta placed at base just above ring organ; antennal blade ca 93–96 Mm long, pale, reaching beyond tip of distal Lauterborn organ; peg of antennal segment 2 placed subapically on segment. Lauterborn organs large, bulbous, 15–21, 19 Mm long; proximal organ placed close to base of segment 2 on 9 Mm long pedicel, apical organ on 15–24, 19 Mm long pedicel; SII slightly plumose, chaetae pectinate, chaetulae simple; S3 split in three branches ( Figure 10E ); pecten epipharyngis consist of three well-developed chaetae and a broad anterior scale; labral lamella with 20–26, 23 (n 53) teeth. Mentum ( Figure 10F ) with 13 teeth, median tooth with weak lateral notches, somewhat paler, all lateral teeth set in equal distance to each other; ventromental plates medially barely reaching second lateral tooth of mentum, MVR 1.12–1.19, 1.17; premandible ( Figure 10G ) with two teeth, well-developed brush; mandible ( Figure 10H ) with pecten mandibularis slightly convex, seta subdentalis 42 Mm long; postoccipital plate ( Figure 10I ) narrow, split in middle.

Body: anterior parapods with long, simple spines; hind parapods with 14–18, 16 simple hooks; L2 apparently simple; anal segment with four narrow anal tubules, 58 Mm long; supraanal seta strong, ca 235 Mm long; procercus ca 24 Mm long with two short (ca 150 Mm long) and four long (ca 575 Mm long) anal setae, the short setae situated individually, and not on the common base of the long setae.

Remarks

The type material was collected in Meiergraben near Lunz by F. Gouin and A. Thienemann 1941–1943, and Thienemann’s field notes (in ZSM) indicate that they found numerous ‘‘ Zavrelia -type’’ larvae which were reared. At least one male and one female from this rearing were sent to Goetghebuer for identification. A male and a female on one pin with the labels ‘‘ Stempellina ciliaris n. sp. ’’ and ‘‘Meiergraben (Autr 1943 D r Thienemann)’’ in Goetghebuer’s handwriting, but without a type label, were found in the Goetghebuer collection in RBINS. These two specimens fit the original description of S. ciliaris ( Goetghebuer 1944) , except that the male antenna is lost, the female antenna has five flagellomeres and the label bears the name of Thienemann instead of Gouin. However, the male antenna could have been lost after description, and the female antenna has a long first flagellomere with two circles of setae and the paralectotype first antennal flagellomere has both median and distal chaetae. Thus, the flagellum probably has erroneously been interpreted as six-segmented (see Goetghebuer 1944, Figure 2b ). Thienemann and Gouin worked closely together in Lunz (A. Thienemann, field notes; E. J. Fittkau, personal communication) and it is reasonable to believe that Goetghebuer got material collected by both Thienemann and Gouin for identification. The two individuals were most certainly examined by Goetghebuer before the description of S. ciliaris and are considered to be part of the type material despite the small discrepancies with the original description. The male is best preserved and is here designated lectotype to stabilize nomenclature. There are three slides with four males, one female, four pupae, nine pupal exuviae, and one larva, and an alcohol vial with two males, one female, three pupal exuviae, and one larva in ZSM which bear the sample number and dates from Thienemann’s and Gouin’s notes from Meiergraben. Six of the pupal exuviae are conspecific with S. ciliaris , while six are conspecific with S. flavidula . The pupal exuviae conspecific with S. ciliaris are thus not regarded as part of the type series, since they cannot be directly linked to the male and female types in the Goetghebuer collection.

Stempellinella ciliaris was listed as a synonym of S. brevis by Brundin (1949), and also treated as such by Thienemann (1950), but examination of the type material of both species revealed that these are morphologically distinct.

Zavrelia inopinata was described as larva from two localities in Romania ( Botnariuc and Cindea-Cure 1954). The type material has not been located and is probably lost (V. Tatole, personal communication). However, the original description is very detailed and well figured, and it is clear to me that the species must be a junior synonym of S. ciliaris . The description of the type localities also fits the localities in which S. ciliaris is found (springs and spring brooks).

Stempellinella ciliaris has been recorded from Austria, France, Germany, Luxembourg, and Romania, but previous records of S. flavidula or S. brevis could actually be S. ciliaris , as these species are quite similar in the adult and immature stages. The abovedescribed species can be separated from S. flavidula by longer spines on the anal point and a longer median volsella in the adult male; a smaller vaginal floor and shorter seminal ducts in the adult female; smaller cephalic tubercles, more chaetae on the thoracic horn and presence of anterior point patches on tergite VII in the pupa; and a higher AAR and longer antennal blade in the larvae. The observed differences in the adult female and larva are small and might not be diagnostic as more material is examined.

The larvae of S. ciliaris build small, straight, transportable cases of sand and detritus, and are typically found in calcareous springs and spring brooks. The pupae of this species have been observed to use the posterolateral spur of the abdominal segment VIII to aid splitting of the thorax at adult emergence ( Ekrem 2005). The species is a recorded host for larvae of the water mite Atracides fonticolus (K. Viets) in a calcareous spring in Luxembourg ( Stur et al. 2005).

Figures

Figure 2. Stempellinella boltoni sp. n., male imago. (A) Head; (B) antennal flagellum; (C) fore, mid, and hind tibiae; (D) hypopygium; (E) anal point lateral view; (F) superior and median volsellae.

Figure 9. Stempellinella ciliaris (Goetghebuer), imagines. (A–F) Male: (A) head; (B) antenna; (C) wing; (D) fore, mid, and hind tibiae; (E) hypopygium; (F) superior, median, and inferior volsellae. (G, H) Female: (G) antenna; (H) genitalia.

Figure 10. Stempellinella ciliaris (Goetghebuer), immatures. (A–C) Pupa: (A) frontal apotome; (B) thorax; (C) abdomen, dorsal view. (D–I) Larva: (D) antenna; (E) clypal seta S3; (F) mentum and ventromental plates; (G) premandible; (H) mandible; (I) postoccipital plate.