Pseudosmittia littoralis (Tokunaga)

Saether, Ole A., 2006, Japanese Pseudosmittia Edwards (Diptera: Chironomidae), Zootaxa 1198, pp. 21-51 : 35-39

Pseudosmittia littoralis (Tokunaga)

( Figs. 10, 11 )

Spaniotoma (Smittia) littoralis Tokunaga, 1936: 303 .

Smittia (Pseudosmittia) littoralis (Tokunaga) ; Goetghebuer (1940 –1950: 107).

Pseudosmittia littoralis (Tokunaga) ; Yamamoto (2004: 89).

Type material JAPAN: Holotype lost, paratypes Wakayama Prefecture, Seto , 5.vii.1934 and Mie Prefecture, Ukijama, 6.viii.1934, M. Tokunaga ( KU) (not examined).

Diagnostic characters The male imago can be separated from other members of the genus by the combination of a strong apical seta on the antenna and an inferior volsella more triangular than in Pseudosmittia xanthostola (Kieffer) and P. brevifurcata (Edwards) . According to Tokunaga (1936: plate viii, fig. 5) it also may have an accessory lobe of the inferior volsella.

Description

Male. No type material was available for loan, but the description by Tokunaga (1936) is reasonably complete. He gives the total length as about 1.2 mm and the coloration as dull black with brownish black abdomen, antennal ratio as 0.5–0.8 (0.6), temporals apparently consisting of outer verticals only, clypeus with 6 or 7 setae, and relative lengths of four last palpomeres as 6:15:17:28.

The median antepronotal lobes are reduced medially, with 2 lateral antepronotal setae; dorsocentrals probably relatively numerous since they are biserial in front; prealars 6–7; scutellum with 6 setae.

The wing as illustrated by Tokunaga (1936: fig. 1) is shown in Fig. 10 . The VR 1 is about 1.65, VR 2 about 1.25, anal lobe obtuse, costa not extended and Cu 1 slightly sinuous.

The middle tibia carries only one apical spur, the hind tibial comb consists of 12–14 setae. The relative lengths of the leg segments (fe to ta 5) are as follows:

Fore leg: 19.5: 19.5: 13.5: 7: 4.5: 3: 3.

Mid leg: 20: 20: 11: 6: 4.5: 3: 3.

Hind leg: 22: 22: 14: 7: 7: 3: 3.

The hypopygium as illustrated by Tokunaga (1936: fig. 5) is reproduced in Fig. 11 . The anal point is triangular with straight sides, pointed, and apparently with about 20 lateral setae. The phallapodeme, sternapodeme and virga are unknown. The inferior volsella is placed posterior on the gonocoxite, and apparently with an accessory lobe.

Female, pupa and larva: The female is inadequately described by Tokunaga (1936). However, according to Tokunaga (1964: 520) the gonocoxite has horn­like posterior extensions, i.e. similar to P. guamensis ( Tokunaga) (Tokunaga 1964: fig. 7e ). The pupa and larva are unknown.

Ecology and distribution

According to Tokunaga (1936: 303) the species was swarming in the evening on a gravelly seashore, about 10 cm above the ground and usually above the zone of the hightide mark. The species is known only from the Pacific coast of Kii Peninsula, Honshu, Japan.

Pseudosmittia mathildae Albu

( Fig. 12 )

? Pseudosmittia sp. B Strenzke (1950: 309).

Pseudosmittia mathildae Albu, 1968: 4 .

Pseudosmittia itachibifurca Sasa et Kawai, 1987: 54 ; Yamamoto (2004: 87). Syn. n.

Pseudosmittia amamibifurca Sasa, 1990a: 132 ; Saether and Ferrington (2003: 3); Yamamoto (2004:

87) as syn. of P. itachibifurca .

Pseudosmittia trilobata ( Edwards, 1929: 364) ; Langton, (1991: 173), pro parte, misidentification.

Pseudosmittia furudobifurca Sasa et Arakawa, 1994: 100 ; Yamamoto (2004: 88) as syn of P. itachibifurca. Syn. n.

Pseudosmittia hibaribifurca Sasa, 1993: 80 ; Yamamoto (2004: 88) as syn of P. itachibifurca . Syn.

n.

Pseudosmittia (Nikismittia) shofukuundecima Sasa, 1998a: 42 ; Yamamoto (2004: 88) as syn of P. itachibifurca. Syn. n.

Diplosmittia amamibifurca (Sasa) ; Saether et al. (2000: 185).

Diplosmittia furudobifurca (Sasa et Arakawa) ; Saether et al. (2000: 185).

Diplosmittia hibarabifurca (Sasa) Saether et al. (2000: 185) .

Diplosmittia itachibifurca (Sasa) ; Saether et al. (2000: 185).

Diplosmittia shofukuundecima (Sasa) ; Saether et al. (2000: 185).

Material examined

JAPAN: Honshu, Toyama Pref., Itachigawa River, holotype ♂ of P. itachibifurca , 16.iv.1986, S. Nagai et al. ( NMST, No. A 115: 03); Honshu, Toyama Pref., Lake Furudo , holotype ♂ of P. furudobifurca , 23.viii.1993, M. Sasa & R. Arakawa ( NMST, No. A 248: 37); Honshu, Toyama Pref., Kurobe, holotype ♂ of P. shoufukuundecima , 30.iv.1996, M. Sasa ( NMST, No. 326: 50); Honshu, Fukushima Pref., Lake Hibara , holotype ♂ of P. hibarabifurca , 8.vi.1991, M. Sasa ( NMST, No. A 223: 90); Nansei Archipelago, Kagoshima Pref., Amami­Oshima Is., Yakkachei River , holotype and paratypes ♂ of P. amamibifurca , 18.iii.1989, M. Sasa & S. Hattori ( NMST, holotype: No. A 179: 21, paratypes: Nos 179: 22–27). Material from China, Germany, Italy, and USA also has been examined.

Diagnostic characters

Antenna without apical strong seta. Antepronotal lobes reduced medially, 2 acrostichals, no supraalars. Postcubitus not forked, R 4+5 ending well proximal to apex of M 3+4. Anal point small and triangular, superior volsella absent, inferior volsella with accessory lobe placed well posterior on gonocoxite, gonostylus bilobed. Female without posterolateral projection on gonocoxite, tergite IX divided by median line only, seminal capsule ovoid and relatively dark. Pupa with stronger anterior and posterior shagreen on tergites, with nose on wing sheath, without setae on anal segment, tergite IX with longitudinal ridge carrying 2–3 rows of strong points, genital sac with spinules in both sexes. Larvae with 3 inner teeth on mandible, 4 pairs of lateral teeth on mentum; posterior parapods with 8 claws, 15–18 m long; antennal blade longer than basal segment, about as long as the latter is wide.

Description All stages of the species will be redescribed in a world­wide revision of Pseudosmittia (in prep.).

Remarks

Pseudosmittia itachibifurca may represent a different species since the AR was described as 0.64–0.84 and the gonostylus as lacking a megaseta. However, non­Japanese specimens show an AR of 0.42–0.60, and a variation of 0.29–0.84 is not unusual in other species of Pseudosmittia . As shown by Yamamoto (2004: 88) the megaseta is present.

Pseudosmittia amamibifurca could be regarded as a subspecies since the AR is lower than in other populations and the type locality (Nansei Archipelago, in the Oceanic (Indo­ Pacific Region) represents the only record from outside the Holarctic Region.

Pseudosmittia mathildae differs from most members of the genus in having a bifurcate gonostylus. For this reason, some past assignments on the basis of the male imago alone have resulted in generic misplacement (see the list of synonyms above). However, the immature stages show the species is an atypical member of Pseudosmittia .

Ecology and distribution

The larvae from the USA are from moist banks along rivers and streams and the larva mentioned by Strenzke as Pseudosmittia sp. B, which is most likely the larva of P. mathildae , was collected from water­saturated peat in a bog. The species is known from Austria, southern Germany, northern Italy, Romania, China, Japan including the Nansei Archipelago, and in the USA from Alabama, Georgia and South Carolina. One of the samples from China, Guangdong, is from well within the Oriental Region.

Figures

FIGURES 10–13. Pseudosmittia spp., male imagines. 10–11. P. littoralis (Tokunaga), wing (10), hypopygium (11), both from Tokunaga (1936). 12. P. mathildae Albu (holotype of P. amamibifurca Sasa), hypopygium. 13. P. nishiharaensis Sasa et Hasegawa (holotype), hypopygium.