Pseudosmittia holsata Thienemann et Strenzke, 1940

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 : 151-155

Pseudosmittia holsata Thienemann et Strenzke

( Figs. 52 , 53 )

Pseudosmittia holsata Thienemann et Strenzke, 1940: 238 , pro parte, holotype male, male pupa, (female pupa and larva = P. virgo ); Strenzke 1950: 286; Saether 2006: 31 ; Langton & Pinder 2007: 136; Schmid 1993: 177, fig. 121; Makarchenko & Makarchenko 2008: 219.

Pseudosmittia hachijotertia Sasa, 1994: 48 ; Yamamoto 2004: 87.

Material examined: AUSTRIA: Lower Austria, Lunz , 6 males or parts of males, 4 females or parts of females, 12 pupal exuviae, 11 larvae, 1–14.v.1941, several incorrectly marked types or paratypes since the species originally was described from Plön, Schleswig-Holstein, Germany ( NMS) . CHINA: Ningxia, Mount Liupan , males, 7.viii.1987, X. Wang ( XW) . GERMANY: Thuringia, Königsee, Salet , drift, males, 3.vii.1986, V. R. Gerstmeier ( ZSM) . USA: South Carolina: Abberville County, Savannah River, Gregg Shoals , moist bank, 1 pupal exuviae, 27.ix.1980, P. L. Hudson ( UMSP) ; Anderson County, Savannah River , 4 miles below Hartwell Dam, moist bank, 1 pupal exuviae, 1 larva, 30.ix.1980, P. L. Hudson ( ZMBN) ; Anderson County, Savannah River, Highway 181 Bridge , moist bank, 1 x 1980, P. L. Hudson . Georgia: Hart County, Savannah River , 4 miles below Hartwell Dam, moist bank, 1 pupal exuviae, 2 larvae, 20. & 30.ix.1980, P. L. Hudson ( CNC, PLH) . JAPAN: Tokyo Metrop., Hachijyo Island, Tohmi Water Fall , holotype male of P. hachijotertia , 29.v.1994, M. Sasa (NMST A 265: 69) .

Diagnostic characters: The male imago differs from the other members of the group in having a superior volsella without microtrichia at the margin, a virga slightly more than 1/3 as long as the gonostylus, conspicuous crista dorsalis and AR of 0.21–0.27. The female imago is characterized by having R 4+5 ending distal to the apex of M 3+4, costa with 23–24 non-marginal setae between R 1 and apex of R 4+5, and LR 1 of 0.53–0.55. Pupa and larva (see group characteristics).

Male imago (n = 6–7, except when otherwise stated)

Total length 1.42–1.76, 1.63 mm (15). Wing length 0.89–1.08, 1.00 mm. Total length/wing length 1.54–1.67, 1.62 (4). Wing length/length of profemur 3.13–3.59, 3.41. Coloration brownish black.

Head. AR 0.21–0.44, 0.28. Terminal flagellomere with rounded apex, 98–173, 120 µm long. Temporal setae 5–6, 5, consisting of 1–2, 1 inner verticals, 1–4, 3 outer verticals and 0–2, 1 postorbitals. Clypeus with 6–8, 7 (5) setae. Tentorium 94–107, 98 µm (4) long; 21–23, 22hachijotertia µm (4) wide. Stipes 85–94 µm (2) long. Palpomere lengths (in µm): 16–21, 19; 25–34, 30; 55–71, 62; 53–66, 61; 71–98, 90. Third palpomere with 1–2, 2 lanceolate sensilla clavata.

Thorax ( Fig. 52 B ). Antepronotal lobes reduced medially, with 1 lateral seta. Scutal projection prominent. Dorsocentrals 5–7, 6; acrostichals 2; prealars 2–3, 3. Scutellum with 2 setae.

Wing ( Fig. 52 A ). VR 1.58–1.76, 1.63 (5). Anal lobe weak. Costal extension 0–11, 7 µm long. R 4+5 ending above or slightly proximal to apex of M 3+4; Cu 1 curved. Brachiolum with 1–2, 1 setae, other veins bare.

Legs. Spur of front tibia 27–34, 31 µm long, spurs of middle tibia 15–18, 17 µm and 14–16, 15 µm long, of hind tibia 30–34, 33 µm and 14–16, 15 µm long. Width at apex of front tibia 16–23, 18 µm, of middle tibia 17–21, 19 µm, of hind tibia 21–27, 25 µm. Comb of 9–10 setae, shortest setae 15–18, 17 µm long, longest setae 23–27, 25 µm long. Lengths and proportions of legs as in Table 29.

Hypopygium ( Fig. 52 C–E ). Anal point 9–26, 19 µm long; tergite IX with 8–14, 10 setae; laterosternite IX with 2– 4, 3 setae. Phallapodeme 38–62, 55 µm long; transverse sternapodeme 43–53, 46 µm long, oral projections only weakly indicated. Virga 14–18, 17 µm long. Gonocoxite 107–130, 121 µm long; superior volsella well developed, reaching to 0.35–0.51, 0.43 gonocoxite length, without microtrichia at inner margin; inferior volsella weak, not distinctly separate from accessory lobe, accessory lobe which reaches to 0.73–0.81, 0.78 gonocoxite length. Gonostylus 46–53, 49 µm long; crista dorsalis preapical, conspicuous; megaseta 6–9, 7 µm long. HR 2.33–2.62, 2.43; HV 3.19– 3.58,3.38 (4).

Female imago (n = 3, except when otherwise stated)

Total length 1.30–1.39 mm. Wing length 0.90–0.97 mm. Total length/wing length 1.40–1.44. Wing length/length of profemur 3.70–3.86. Coloration as in male.

Head. AR 0.44–0.46. Lengths (in µm) of flagellomeres: 50–55, 34–39, 37–42, 41, 71–75 ( Strenzke 1950, fig. 69). Temporal setae 4–6, including 1–2 inner verticals, 1–2 outer verticals and 2 postorbitals. Clypeus with 8–13 setae. Tentorium 78 µm (1) long, 11 µm (1) wide. Stipes not measurable. Palpomere lengths (in µm): 16–21, 27–29, 46–55, 55– 57, 85–91 (2). Third palpomere with 2 lanceolate sensilla clavata. Coronal suture absent.

Thorax. Antepronotal lobes reduced medially, lateral setae obscured. Dorsocentrals 5–6, acrostichals 2, prealars 2–3 (2. Scutellum with 2 setae).

Wing ( Fig. 53 A ; Strenzke 1950 fig. 30). VR 1.52–1.54. Anal lobe weak. Costal extension 9–25 µm long. R 4+5 ending distal to apex of M 3+4; Cu 1 sinuate. Brachiolum with 1–2 setae, costa between R 1 and R 4+5 with 23–24 non-marginal setae, costal extension with 2–3 non-marginal setae, R with 6–7, R 1 with 3–4, R 4+5 with 10 setae, other veins bare.

Legs. Spur of front tibia 21 µm long, spurs of middle tibia 14 µm (2) and 11–14 µm (2) long, of hind tibia 25–30 µm and 16 µm long. Width at apex of front and middle tibiae each 18–21 µm, of hind tibia 25–27 µm. Comb of 10–11 (2) setae, shortest setae 16 µm (2) long, longest setae 27 µm (2). Lengths and proportions of legs as in Table 30.

Abdomen. Setae not countable. Genitalia. Gonocoxite and tergite setae not measurable, tergite IX perhaps undivided. Cercus 48–66 µm long. Apodeme between tergite and gonocoxite 66–78 µm long. Seminal capsule brown, almost circular; 57 µm long, excluding 27–37 µm m long neck, 50–51 µm wide, microtrichia not observed. Notum 64–69 µm (2) long.

Pupa (n = 10)

Total length 1.53–2.02, 1.85 mm. Exuviae nearly colorless, with only slight yellowish tinge on margins of cephalothorax especially along wing sheaths.

Cephalothorax. Frontal apotome nearly smooth. Frontal setae, longer precorneals, longer median antepronotal, single lateral antepronotal and postorbital setae all about 40–60 µm long. Shorter precorneal, shorter median antepronotal and longer dorsocentral setae (usually Dc 4) all about 20–30 µm long. Shorter dorsocentral setae all about 10–20 µm long. Scutum smooth or with a few scattered spinules. Distance between Dc 1 and Dc 2 41–80, 62 µm; between Dc 2 and Dc 3 2–11 µm; between Dc 3 and Dc 4 2–5, 3 µm.

Abdomen ( Fig. 53 B, C ). Tergite I with anterolateral shagreen; T II–VII with coarse shagreen covering most of each segment except a narrow bare anterior band, stronger spinules anteriorly and posteriorly; T VIII with anterior and posterior band of spinules; T IX with shagreen on most of tergite. Sternite I–III bare; S IV–VI with sparse anterolateral shagreen and a few posterior spinules; S VII–VIII with broader anterior band of spinules, bare posteriorly; S IX bare. Tergite VII in male and T VI and VIII in females with posterior spinules set off as short spines. Tergal conjunctive IV/ V with 20–79, 41 spinules; V/VI with 20–76, 40; VI/VII with 20–81, 41; VII/VIII with 0–2, 0 spinules. Sternal conjunctive IV/V with 18–55, 31 spinules; V/VI with 22–61, 36; VI/VII with 23–57, 45; VII/VIII with 15–47, 27; VIII/IX with 3–13, 8 spinules in male, bare in 5 females. Anal segment on each side with a pair of posterolateral mounds, each mound with two strong contiguous teeth with seta between, setae about 25–30 µm long. Genital sac of male overreaching anal segment by 48–55, 50 µm; of female by 0–9, 16 µm.

Fourth instar larva (n = 8–11, except when otherwise stated)

Total length 1.51–3.18, 2.45 mm (13). Head capsule length 0.15–0.22, 0.16 mm (14). coloration yellowish white with some brown to violet spots on thorax and preanal segment, head pale brownish yellow.

Head. Antenna as in Fig. 53 D (also see Strenzke 1950, fig. 74). Length of antennal segments (in µm): 7–9.5, 8.5; 2–3.5, 3; 2–2.5, 2; 2–2.5, 2.5. AR 0.94–1.39, 1.10. Basal antennal segment 9–11, 10 µm wide; blade 9–13.5, 10 µm long; accessory blade 3.5–8, 4.5 µm long. Sensilla basiconica 2.5–3.5, 2.5 µm long. Subapical style of second segment 3.5–4.5, 4 µm (7) long. Labrum and epipharyngeal area as in Strenzke (1950, fig. 75). Premandible ( Fig. 53 E ) 37–48, 42 µm m long. Mandible ( Fig. 53 F ; also see Strenzke 1950, fig. 76b) 66–82, 75 µm long; with 3 inner teeth, apparently without seta subdentalis; seta interna absent. Mentum as in Fig. 53 G (also see Strenzke 1950, fig. 77b), median tooth 21 µm wide (2), ventromental plate 5–6, 6 µm (2) wide in flattened mentum Postmentum 46–66, 58 µm long.

Abdomen. Anterior parapods ( Strenzke 1950, fig. 73b) completely fused with 15 longer claws on each parapod. Posterior parapods ( Fig. 53 H ) 57–85, 66 µm long, each with 5 (12) claws 6.5–10 µm (2) long. Dorsal anal tubules ( Fig. 53 H , Strenzke 1950, fig. 72) 37–73, 54 µm long, 16–32, 21 µm wide. Ventral anal tubules 50–80, 72 µm long, 14–23, 21 µm wide with 1–2 weak constrictions.

Ecology and distribution

According to Strenzke (1950: 292) the larvae occur on submersed moss on solid substrates especially along the shores of lakes, but also in springs. The Nearctic larvae all were collected from a moist bank of the Savannah River. The species is known from Austria, Britain, France, Germany, Hungary, Italy, The Netherlands, Romania, Russia including the Far East, Spain, Sweden, Switzerland, China, Japan and the USA.

Figures

FIGURE 52. Pseudosmittia holsata Thienemann et Strenzke, male. A—wing; B—thorax; C—hypopygium, dorsal aspect; D— hypopygium, ventral aspect; E—gonostylus.

FIGURE 53. Pseudosmittia holsata Thienemann et Strenzke, female and immatures. A—female wing; B—female pupa, posterior tergites; C—male pupa, posterior tergites; D—larval antenna; E—larval premandible; F—mandible; G—mentum; H— larva, posterior apex.