Hydrosmittia montana (Strenzke) Ferrington Jr & Saether, 2011

Ferrington Jr, Leonard C. & Saether, Ole A., 2011, A revision of the genera Pseudosmittia Edwards, 1932, Allocladius Kieffer, 1913, and Hydrosmittia gen. n. (Diptera: Chironomidae, Orthocladiinae) 2849, Zootaxa 2849 (1), pp. 1-314 : 118-120

Hydrosmittia montana (Strenzke) comb. n.

( Fig. 41 )

Pseudosmittia virgo montana Strenzke, 1950: 303 .

Pseudosmittia virgomontana Ashe & Cranston, 1991: 223 , lapsus.

Material examined: AUSTRIA: Lower Austria, Lunz , holotype female, 11.v.1941, No. 644a (GP736)( NMS) ; female, pupal exuviae, labeled Typus but date 9.v.1941, and therefore not associated with female holotype No. 644a (GP729)( NMS) ; 1 female, 7 pupal exuviae, 7 larvae, as holotype, Nos. 678 and 698 (GP722–725, 727, 728)( NMS) . THE NETHERLANDS: Noord-Brabant, Tilburg , along the edge of a canal, 4 females, 20.iv.1990, H. K. Moller Pillot ( UMSP, ZMBN) .

Diagnostic characters: The female imago differs from P. virgo in having 23–42 non-marginal setae on costa between FR and apex of R 4+5. The pupa has frontal setae and anal macrosetae, frontal apotome with several wrinkles but no distinct frontal warts, spinules or tubercles and abdomen slightly tinged with yellow. The larva is characterized by having 3 inner teeth on the mandible, 9–11 claws on the posterior parapods all less than 40 µm long, and anal tubules 71–117 µm long with 1–2 constrictions.

Female imago (n = 1–2)

Total length 1.80 mm. Wing length 1.17–1.20 mm. Total length/ wing length 1.54. Wing length/length of profemur 3.71–3.98. Coloration brownish yellow with brownish black vittae, preepisternum and postnotum, and brownish yellow scutellum. Legs and antennae brown, abdomen brownish yellow.

Head. AR 0.42–0.46. Flagellomeres 2–5 slightly flask-shaped, no apical strong seta. Length (in µm) of flagellomeres: 62–64, 41–43, 42–43, 39–41, 73–85. Temporal setae 4, including 1 weak, 11 µm long, inner vertical and 3 outer verticals. Clypeus with 9 setae. Tentorium 94–105 µm long, 11–14 µm wide. Stipes 91 µm long, width not measurable. Palpomere lengths (in µm): 27, 37–39, 64–79, 62–73, 96–98. Third palpomere with 2 lanceolate sensilla clavata. Coronal suture complete.

Thorax. Median antepronotal lobes well developed, with 1–2 lateral setae. Dorsocentrals 7–9, acrostichals 2, prealars 3, supraalar seta absent. Scutellum with 4 setae.

Wing ( Fig. 41 A ). VR 1.34–1.40. Anal lobe well developed. Costal extension 27–46 µm long, with false vein extending to 91–126 µm. R 4+5 ending distal to apex of M 3+4; Cu 1 sinuate. Brachiolum with 1 seta, costa between FR and apex of R 4+5 with 23–42 non-marginal setae, costal extension with 4–5 setae, R with 3–5, R 1 with 2–3, R 4+5 with 5–7 setae, other veins bare.

Legs. Spur of front tibia 21–23 µm long, spurs of middle tibia 16–21 µm and 14–18 µm long, of hind tibia 29 µm and 14 µm long. Width at apex of front and middle tibiae each 21–24 µm, of hind tibia 26–32 µm. Comb setae not measurable. Lengths and proportions of legs as in Table 22.

Abdomen. Sternite VIII with about 28 setae. Setae not measurable on other tergites and sternites. Genitalia ( Fig. 41 B–F ). Gonocoxite with 2 strong and 7 weak setae. Tergite IX divided, with altogether about 20 setae. Cercus 71–82 µm long. Apodeme against gonocoxite 69 µm long. Seminal capsule 57–59 µm long, excluding 21 µm long neck, 46–50 µm wide, microtrichia not observed. Notum 73 µm long.

Pupa (n = 7)

Total length 1.96–2.59, 2.40 mm. Exuviae tinged with pale yellow.

Cephalothorax. Frontal apotome with wrinkles, without warts, frontal setae present. Longer precorneals and ventral median antepronotal setae 45–70 µm long; frontal seta, postorbitals, shorter precorneal, dorsal median antepronotal, larger lateral antepronotal and Dc 4 each about 50 µm long; Dc 1, Dc 2, and Dc 3 each 10–25 µm long; shorter lateral antepronotal indicated or perhaps occasionally absent. Distance between Dc 1 and Dc 2 53–91, 69 µm; between Dc 2 and Dc 3 2–5, 3 µm; between Dc 3 and Dc 4 1–9, 3 µm.

Abdomen. ( Fig. 41 G ). Tergite I with anterolateral shagreen, T I–IX with even shagreen over whole tergite except bare preapically on T VIII. Sternite I with anterolateral spinules, S II–VI with anterior and posterior spinules, S VII with spinules over most of segment, S VIII with broad anterior band of spinules, S IX with a few weak anterolateral spinules or bare (1 of 7 specimens examined). Tergal conjunctives II/III with 12–35, 22 spinules; III/IV with 20–53, 32; IV/V with 35–45, 43; V/VI with 30–62, 45; VI/VII with 20–56, 37; VII/VIII with 0–15, 4 spinules (weak spinules present on 2 of 7 specimens examined). Sternal conjunctives III/IV with 0–7 spinules; IV/V with 63– 95, 79; V/VI with 50–110, 81; VI/VII with 58–102, 78; VII/VIII with 20–46, 32 spinules. Anal segment with about 35 µm long basal seta and 2 apical setae about 25–30 µm long.

Fourth instar larva (n = 6–7, except when otherwise stated)

Total length 3.17–3.60, 3.42 mm. Head capsule length 0.23–0.28, 0.25 mm. Head capsule yellowish brown, thorax yellow, abdomen whitish yellow.

Head. Antenna as in Fig. 41 H . Length of antennal segments (in µm): 9–11, 10; 2.5–3.5, 3; 1–2, 1.5; 2. AR 1.43– 1.67, 1.55. Basal antennal segment 10.5–11.5, 11 µm wide; blade 8–10, 9 µm long; accessory blade 4.5–5.5, 5.5 µm long. Sensilla basiconica 2.5–3.5, 3 µm long. Subapical style of second segment 3.5, 4.5, 4.5 µm long. Premandible ( Fig. 41 I ) 46–50, 48 µm long. Mandible ( Fig. 41 J ) 85–89, 87 µm long; seta subdentalis 7 µm (2) long. Mentum as in Fig. 41 K , with 4 lateral teeth (no specimens with 5 teeth as mentioned by Strenzke), median tooth 22–25 µm wide (2), ventromental plate 6–8 µm (2) wide in flattened mentum. Postmentum 69–77, 73 µm long.

Abdomen. Anterior parapods ( Fig. 41 M ) fused for most of their length, 57–69, 60 µm (5) long; each with about 30 longer claws. Posterior parapods ( Fig. 41 L ) 69–103, 89 µm long; with 9–11, 10 claws, 27–30 µm (2) long. Dorsal anal tubules 71–103, 83 µm long, 25–32, 28 µm wide at base, 7–21, 14 µm wide at apex. Ventral anal tubules 91–117, 101 µm long, 21–27, 24 µm wide at base, 9–18, 14 µm wide at apex. Tubules with 1 or 2 constrictions.

Ecology and distribution

According to Strenzke (1950: 308) H. montana and H. virgo both live in submersed moss on solid substrates in the littoral zones of lakes. The species is recorded only from the type locality in Austria and from along the edge of a canal in Tilburg, The Netherlands.

Figures

FIGURE 41. Hydrosmittia montana (Strenzke) comb. n., female, immatures. A—female wing; B—female genitalia, ventral view; C—female genitalia, dorsal (partly lateral) view; D—dorsomesal lobe; E—apodeme lobe; F—ventrolateral lobe; G— pupa, posterior segments, lateral view; H—larval antenna; I—larval premandible; J—larval mandible; K—larval mentum; L— posterior end of larva; M—anterior parapods of larva.