Simulium (Boreosimulium) konoi ( Takahasi, 1950 )

Kim, Sam-Kyu, 2020, Unrecorded subgenus of black fly (Diptera: Simuliidae) from Korea, Journal of Species Research 9 (1), pp. 19-25 : 20-23

Simulium (Boreosimulium) konoi ( Takahasi, 1950)

( Figs. 1-4 )

Nevermannia konoi Takahasi, 1950: 1556 . Type locality: Tottori, Honshu , Japan.

Simulium (Nevermannia) yamayaense Ogata & Sasa, 1954: 326-327 . Type locality: Honshu, Japan; Takaoka & Okazawa, 1988: 99 (Japanese list); Uemoto, 1991: 191 (synonymization).

Simulium (Nevermannia) liaodongense Sun, 2012: 46- 49 . Type locality: Liaoning, China; Adler & Crosskey, 2014 (synonymization).

Simulium sp. J-9 Bentinck, 1955: 6; Takahasi, 1971 (synonymization).

Simulium (Eusimulium) sp. Ogata & Sasa, 1955: 14 (Japanese key).

Simulium (Boreosimulium) konoi: Sato et al., 2004 (taxonomy, redescription); Adler, 2019 (world list).

Simulium (Nevermannia) konoi: Ogata & Sasa, 1954: 328 (Japanese list and key); Ogata & Sasa, 1955: 11 (Japanese list and key); Shogaki, 1956: 275 (Japanese list); Ogata et al., 1956: 76-77 (description); Takahasi, 1971: 80 (taxonomic notes); Takaoka & Okazawa, 1988: 98 (Japanese list).

Eusimulium konoi: Orii et al., 1969: 3 (Japanese key); Uemoto, 1991: 191 (taxonomic note); Uemoto, 2005: 1017 (Japanese key, illustration).

Simulium (Eusimulium) konoi: Ogata & Uemoto, 1971: 80 (illustration); Matsuo & Uemoto, 1975: 130-133 (morphology).

Simulium (Gomphostilbia) konoi: Uemoto, 1985: 330 (Japanese key).

Simulium (Eusimulium) yamayaense: Ogata et al., 1956: 74 (morphology); Shogaki & Shimizu, 1956: 373 (illustration); Okamoto, 1958: 583 (taxonomic notes, illustration); Ogata & Uemoto, 1971: 77 (illustration); Uemoto, 1985: 330 (Japanese key).

Eusimulium yamayaense: Orii et al., 1969: 9-11 (Japanese key).

Cnetha konoi: Yankovsky, 2001: 305 (Russian key).

Cnetha konoi: Ono, 1979 (misidentification of Simulium oligotuberculatum ( Knoz, 1965)) .

Diagnosis. This species can be distinguished from other black flies by the following combination of characteristics: female cibarium equipped with oblique rows of denticles; male ventral plate well-developed W or inverted V­shaped; pupa with 4 gill filaments; larva with thorax and abdomen densely covered with short branched dark setae; larval antenna with 3 hyaline bands.

Description. Female ( Fig. 1 ). Body length ( Fig. 1A ): 2.6- 2.8 mm (n = 10). Head ( Fig. 1B ). As wide as thorax. Eye dichoptic. Antenna 11 segmented, terminal segment with 3-4 apical setae. Frons dark brown to black, dull densely covered with whitish golden hairs. Clypeus dorsally and laterally with dark brown, medially brown with whitish hairs, pruinosity. Maxillary palp ( Fig. 1C ) 5 segmented, proportional ratio of 3 rd to 5 th segments 1: 1.2-1.3: 2.4- 2.6; sensory vesicle 0.4 × as long as 3 rd segment. Mandible with ca. 25 serrations. Maxillary lacinia ( Fig. 1C ) with 23-27 teeth. Cibarium ( Fig. 1D, E ) with ca. 70-80 water drop-shaped oblique rows of denticles anteriorly. Hypopharynx with 20-30 spine-like serrations. Thorax ( Fig. 1F ). Wing length: 2.5-2.7 mm. Basal section of radius with dorsal hairs. Scutum dark brown to black with densely covered with whitish golden hairs. Scutellum light brown with long golden hairs, apically with long black hairs. Pleural membrane light brown, bare. Katepisternum brown, bare. Legs. All femora and tibiae brownish yellow with apex brown. Tarsi dark brown. Hind leg with basitarsus ( Fig. 1G ) with calcipala distinct, 1.6× as long as tarsomere 1-4 combined. Pedisulcus distinct. Tarsal claw with well-developed thumblike lobe, 0.64 × as long as claw. Abdomen. Brown to dark brown, moderately covered with whitish hairs except abdominal segments 3-7 with dark long hairs near each spiracles. Genitalia ( Fig. 1H ). Genital fork with space between each arms semi-round. Anal lobe moderately produced ventrally, rounded, 13-17 long hairs. Cercus small, rounded posteriorly, setose. Spermatheca ( Fig. 1I ) slightly longer than wide, with distinct reticulate pattern.

Male ( Fig. 2 ). Body length ( Fig. 2A ): 2.4-2.7 mm (n = 10). Head ( Fig. 2B ). Wider than thorax. Eye holoptic. Upper corneal facets consisting of 15-17 vertical rows and 20- 22 horizontal rows. Antenna ( Fig. 2C ) 11 segmented, terminal segment with 3-5 apical setae. Clypeus dark brown, pruinosity, moderately covered with yellowish hairs. Maxillary palp ( Fig. 2D ) 5 segmented, proportional ratio of 3 rd to 5 th segments 1: 1.1-1.3: 2.4-2.6; sensory vesicle 0.2 × as long as 3 rd segment. Maxillary lacinia with 15-18 short setae, not well serrated. Cibarium ( Fig. 2E ) without denticles. Hypopharynx with 15-20 apical setae. Thorax ( Fig. 2F ). Wing length: 2.2-2.5 mm. Basal section of radius with dorsal hairs. Scutum brownish black, densely covered with golden hairs, posteriorly with long reclinate hairs. Scutellum yellowish brown with long black hairs and sparse golden hairs. Pleural membrane brown, bare. Katepisternum brown, bare. Legs. All femora and tibiae yellowish brown with apex brown. Tarsi brown to dark brown. Hind leg with basitarsus ( Fig. 2G ) with calcipala distinct, 1.4 × as long as tarsomere 1-4 combined. Pedisulcus distinct. Tarsal claw small without thumb-like lobe. Abdomen brown to dark brown with all hairs brown to dark brown. Genitalia ( Fig. 2H, I ). Gonostylus slender, tapered to pointed apex, gently curved inwardly, with single small spinule. Ventral plate with well developed median keel, W or inverted V­shaped in ventral view. Median sclerite elongate, thin. Cercus small, rounded. Paramere moderate sized, 8-11 hooks, each with 10- 15 short setae.

Pupa ( Fig. 3 ). Body length ( Fig. 3A, B ): 2.7-3.0 mm (n = 10). Body ( Fig. 3B, C ) brown to reddish­brown ground color. Gill ( Fig. 4B ) with 4 filaments, equal in size, 0.8 × as long as pupal body length (2.2-2.5 mm), angle between uppermost and lowermost filaments less than 90°. Cephalic plate and vertex ( Fig. 3D ) bare, without tubercles. Frons with 3 pairs of short trichomes, simple, less than half the length of facial trichome, only visible in high magnification; face with 1 medium long trichome, simple, about half the length of thoracic trichomes. Thorax ( Fig. 3D ) bare anteriorly, moderately covered with small tubercles posteriorly; thoracic trichome ( Fig. 3E ) in 6 pairs, simple (unbranched), long. Abdomen ( Fig. 3C ). Abdominal tergites III and IV with 4 anteriorly directed spin hooks on posterior margin. Tergites V- IX with spine combs, spines on tergite V smallest, tergite VIII largest. Terminal hooks well developed. Cocoon ( Fig. 3A ) slipper-shaped, tightly woven, as long as pupa.

Larva ( Fig. 4 ). Body length ( Fig. 4A, B ): 5.3-5.7 mm (n = 10). Body ( Fig. 4A, B ) reddish­brown or brownish­grey ground color. Gill histoblast ( Fig. 4A, B ) 4 filaments. Head ( Fig. 4C ) with head spots positive; anteromedial spots 4, separated, distinct; first and second anterolateral spots obliquely elongated, separated, parallel with each other; posteromedial spots narrow, distinct, 1.3× as long as anteromedial spots; first and second posterolateral spots separated, distinct. Single spot under ocellus. Antenna ( Fig. 4D ) brown with 3 hyaline bands, 1.2 × as long as labral fan stem, proportional ratio of antennal segments 1: 1.4: 0.8. Labral fan with 35-38 primary rays. Postgenal cleft ( Fig. 4E ) not clearly defined, round, as long as wide, laterally with elongate spot. Hypostoma ( Fig. 4F ) with 9 teeth, lateral and median teeth subequal in length, basally with 3-4 hypostomal setae. Subesophageal ganglion darkly pigmented. Thorax and abdomen densely covered with short branched black setae dorsally and laterally ( Fig. 4G, H ). Rectal papillae ( Fig. 4H, I ) of 3 compound lobe with 6-7 secondary lobules. Ventral tubercle absent ( Fig. 4I ). Posterior proleg ( Fig. 4J ) with 10-12 hooks (posterior circlet), 60-65 rows.

Specimens examined. Korea: Gyeonggi-do, Gapyeonggun, Buk-myeon, Jeokmok-ri , Gapyeongcheon stream, 37°57 ʹ 48 ʺ N, 127°26 ʹ 58 ʺ E, altitude 290 m. 10.v.2019, SK Kim (159 ultimate, 187 penultimate, 72 early instar larvae, 50 pupae (except for rearing), 16♂, 32$; Gyeonggi­do, Gapyeong­gun, Buk­myeon, Dodae­ri, Myeongjicheon stream, 37°56 ʹ 07 ʺ N, 127°29 ʹ 18 ʺ E, altitude 210 m, 22.v.2019, SK Kim (1 ultimate, 6 penultimate instar larvae).

Distribution. Korea (Gyeonggi-do, new record), China (Liaoning), Japan (Hokkaido, Honshu, Kyushu, Shikoku), Siberia (Far East).

Stream information. Two streams, the only localities where larvae and pupae of S. konoi were collected so far, were separated by Mt. Myeongjisan (1,267 m) by a distance of 4.6 km. Both streams were medium to large-sized streams with moderate to rapid flow and stream beds consisting of boulders and rubble, and totally exposed to the sun. Edges of the streams were lined with trailing vegetations including reeds. The streams were 10-20 m wide and 15-20 cm deep, but the streams were partially dried up due to spring drought.

Biological notes. Larvae were collected from trailing vegetation, submerged twigs, and dead leaves. Body colors of fresh larvae were brownish red or brownish grey when fully matured. Specimens were collected along with Prosimulium kiotoense , Simulium japonicum , Simulium malyschevi , Simulium suzukii , and Simulium yamatoense (the latter was previously misidentified as S. rufibasis ). All larvae and pupae were collected only twice in May 2019 from two streams, and I failed to collect S. konoi in subsequent attempts in other months at the same streams, suggesting S. konoi is univoltine as Sato et al. (2004) suggested. In Japan as well, larvae and pupae of S. konoi were collected only in April and had not been found in other months ( Sato et al., 2004).

Remarks. Subgenus Boreosimulium contains three species-groups: annulus species-group where S. konoi belongs to, baffinense species-group, and johannseni species-group ( Adler, 2019). The most distinctive characteristic of S. konoi is several rows of denticles on the female cibarium as Bentinck (1955) and Sato et al. (2004) recognized. Placement of S. konoi in the subgenus Boreosimulium is somewhat problematic since S. konoi possess many characteristics that do not match the diagnosis for Boreosimulium , such as denticles on the cibarium of the female, the bi-colored legs of the female, and short black setae on the larval abdomen. Cibarial armature are present in species of Psilopelmia , Psilozia and Hemicnetha ( Adler et al., 2004) , but the shape and position of armature is different in S. konoi . Furthermore, chromosomal analysis showed that the chromosomes of S. konoi were very different and it did not match the typical chromosomes of Boreosimulium (e.g., annulus species-group) (Peter H. Adler, pers. comm.). Features of Korean S. konoi specimens matched those of Japanese specimens in almost all details, with some degree of geographical variation, such as ventral tubercle on larval abdominal segment IX and shape of larval head spots. Due to the autapomorphy and other characters found in S. konoi , the current placement of S. konoi in the subgenus Boreosimulium or species-group assignment is tentative, and future research is warranted to clarify the placement of the S. konoi in the subgenus or species-group.

Figures

Fig. 1. Female of Simulium (Boreosimulium) konoi. (A) Body, lateral view; (B) Head, frontal view; (C) Maxillary palp with lacinia; (D) Cibarium with hypopharynx; (E) Cibarium; (F) Body, dorsal view; (G) Hind leg with basitarsus and tarsomeres; (H) Abdomen and genita- lia, ventral view; (I) Spermatheca. Scale bars, 1 mm (A, F); 200 μm (B, H); 100 μm(C, D, G); 50μm (I); 20μm (E).

Fig. 2. Male of Simulium (Boreosimulium) konoi. (A) Body, lateral view; (B) Head, frontal view; (C) Antenna; (D) Maxillary palp with lac- inia; (E) Cibarium with hypopharynx; (F) Body, dorsolateral view; (G) Hind leg with basitarsus and tarsomeres; (H) Genitalia, end view; (I) Genitalia, ventral view(slide mounted). Scale bars, 1 mm (A, F); 200μm (B); 100μm (C-E, G-I).

Fig. 3. Pupa of Simulium (Boreosimulium) konoi. (A) Pupa with cocoon, lateral view; (B) Pupa, lateral view; (C) Abdomen, dorsal view; (D) Head and thorax (gill filaments removed), frontal view; (E) Head and thorax, ventrolateral view. Scale bars, 1 mm(A, B); 500 μm (C-E).

Fig. 4. Larva of Simulium(Boreosimulium) konoi. (A, B) Larva, lateral and dorsal view; (C, D) Head, dorsal view; (E) Head, ventral view; (F) Hypostoma (slide mounted); (G) Abdominal setae (slide mounted); (H) Posterior end of abdomen, dorsal view; (I) Posterior end of ab- domen, lateral view; (J) Posterior circlet (slide mounted). Scale bars, 1 mm (A, B); 500μm (C, E, H, I); 200μm (D); 100μm (F, J); 50μm (G).