Pseudosmittia holsata Thienemann et Strenzke, 1940

Saether, Ole A., 2006, Japanese Pseudosmittia Edwards (Diptera: Chironomidae), Zootaxa 1198, pp. 21-51 : 31-33

Pseudosmittia holsata Thienemann et Strenzke

( Fig. 5 )

Pseudosmittia holsata Thienemann et Strenzke, 1940: 238 .

Pseudosmittia hachijotertia Sasa, 1994: 48 ; Yamamoto (2004: 87). Syn. n.

Material examined

JAPAN: Tokyo Metrop., Hachijyo Island, Tohmi Water Fall , holotype ♂ of P . hachijotertia, 29.v.1994, M. Sasa (NMST, No. A 265: 69). In addition material from Austria, China, Germany, and USA has been examined.

Diagnostic characters

The male imago has 2 acrostichals, superior volsella consisting of rounded, well developed basal swelling of inner margin of gonocoxite and lacking microtrichia at the margin, triangular anal point, virga slightly more than 1/3 as long as the gonostylus, crista dorsalis preapical and conspicuous, and AR of 0.21–0.27. The female imago is characterised by R 4+5 ending distal to the apex of M 3+4, costa with 23–24 non­marginal setae between R 1 and apex of R 4+5, and LR 1 of 0.53–0.55. Pupa with stronger anterior and posterior, weaker median shagreen on tergites, without spinules on tergal conjunctives III/ IV, anal segment with 2 posterolateral mounds each with 2 strong contiguous teeth with setae between. Larva with 3 inner teeth on mandible, mentum with 4 pairs of lateral teeth, posterior parapods with 5 claws, and antennal blade subequal in length to width of basal antennal segment.

Description The species will be redescribed in a world­wide revision of Pseudosmittia (in prep.).

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, Germany, China, Japan and the USA.

Pseudosmittia jintuoctava (Sasa) comb. n.

( Figs. 6, 7 )

Mesosmittia jintuoctava Sasa, 1990b: 46 ; Yamamoto (2004: 51).

Material examined JAPAN: Honshu, Toyama Pref., Jinshu River at Ousawano , holotype ♂, 30.v.1989, M. Sasa ( NMST, No. A 207: 38, misspelled Mesosmittia jintunona ) .

Diagnostic characters

The male imago differs from other Japanese species of the genus by antepronotal lobes not reduced medially, about 4 acrostichals, supraalar present, superior volsella indicated as basal swelling, and inferior volsella with accessory lobe.

Description

Male (n = 1). Total length 1.98 mm. Wing length 1.10 mm. Total length/wing length 1.80. Wing length/length of profemur 2.64. Coloration pale brown with darker brown vittae, preepisternum, scutellum and postnotum.

Head ( Sasa 1990b: fig. 9a). AR 0.61. Terminal flagellomere 244 m long, apically slightly expanded, then abruptly narrowed with pointed apex. Temporal setae 4, consisting of 1 inner vertical and 3 outer verticals. Clypeus with 6 setae. Tentorium 198 m long, 30 m wide. Stipes 83 m long, 26 m wide. Palpomere lengths (in m): 26, 38, 56, 56, 71; third palpomere with 2 sensilla clavata.

Thorax ( Sasa 1990b: fig. 9c). Antepronotal lobes not reduced medially, antepronotum with 4 lateral setae. Dorsocentrals 5, acrostichals 4, prealars 3, and 1 supraalar seta. Scutellum with 6 setae.

Wing ( Fig. 6 ; Sasa 1990b: fig. 9d). VR 1.27. Anal lobe weak. Costal extension 26 m long. R 4+5 ending distal to apex of M 3+4; Cu 1 distinctly sinuate. Brachiolum with 1 seta, other veins bare.

Legs. Spur of fore tibia 34 m long; spurs of middle tibia 19 m and 15 m long; of hind tibia 38 m long, the other lost ( Sasa 1990b: figs. 9e–g). Width at apex of fore tibia 26 m, of middle tibia 30 m, of hind tibia 34 m. Number of setae in comb not measurable, but setae 21–34 m long. Lengths and proportions of legs as in Table 2 .

Hypopygium ( Fig. 7 ; Sasa 1990b: fig. 9 h). Anal tergite apparently with complex, possibly divided anal point or longitudinal ridge (specimen distorted); tergite IX with about 8 setae; laterosternite IX apparently with 2 setae. Phallapodeme 95 m long; transverse sternapodeme 59 m long, with barely projecting oral projections. Virga 6 m long, 5 m wide at base. Gonocoxite 166 m long; superior volsella barely indicated as basal swelling; median volsella absent; inferior volsella reaching to 0.66, accessory lobe to 0.75 of gonocoxite length. Gonostylus 55 m long; megaseta broad, 9 m long, 5 m wide. HR 2.50, HV 2.99.

Female, pupa and larva: Unknown.

Remarks

The hypopygium of the only known specimen is squashed and partly on its side. The interpretation of the anal tergite having a ridge similar to that in Mesosmittia Brundin thus may be incorrect.

Distribution The species is known only from Japan.

Figures

FIGURES 5–9. Pseudosmittia spp., male imagines. 5. P. holsata Thienemann et Strenzke (holotype of P. hachijotertia Sasa), hypopygium. 6–7. P. jintuoctava (Sasa), wing (6), hypopygium (7). 8–9. P. kisotriangulata Sasa et Kondo, wing (8), hypopygium (9).