Clairvillia nigra ZEEGERS, 2023

Zeegers, Theo & Kim, Wonwoong, 2023, Contribution to the knowledge of Tachinidae (Diptera) of Korea, Linzer biologische Beiträge 54 (2), pp. 669-678 : 673-676

Clairvillia nigra ZEEGERS nov.sp. ( Figs 2 , 3A , 4A )

H o l o t y p e: male: Republic of Korea, Bupyeong-ri, Gangcheon-myeon, Yeoju-si, Gyeonggi-do, 37 o 15’23" N 127 o 45’19" E, 5.vi.2021, swept from low grass, leg Wonwoong Kim.Will be deposited in the collection of Naturalis Biodiversity Center, Leiden, the Netherlands.

D i a g n o s i s: Generally shiny black species (thorax, scutellum, abdomen, legs, antenna, palpus). Ocellar seta very weak, reclinate. Mid tibia with only one ventral seta. Male genitalia generally similar to Clairvillia biguttata (MEIGEN, 1824) , but syncercus in lateral view only as large as gonites-complex.

D e s c r i p t i o n: Generally shiny black species, with black thorax, scutellum, abdomen, legs, antenna and palpus ( Fig. 2 ). Frontal vitta dull black, inner margin of fronto-orbital plate like a shiny black varnish, fronto-orbital plate otherwise white and parafacial shiny white. Hairs on gena completely and on backside of head mostly black, light hairs restricted to the lower part of the occiput. Thoracic dorsum with an inconspicuous silverygrey rectangular spot on postpronotal lobe, reaching backwards towards transverse suture. Upper and lower calypter white, haltere dark. Wing with strong yellow venation and dark yellow colouration at wing base, more so in costal cell; tegula and basicosta black.

Vertex narrow, about 1/3th of the width of one eye. Frontal vitta before anterior ocellus twice as broad as fronto-orbital plate. Head in lateral view: vibrissal angle slightly projecting, gena narrow, about 1/5th of larger diameter of an eye, parafacial narrower than gena and narrower than third antennal segment. Proboscis about 4.5 times as long as its diameter. Eye with ommatidia in upper 2/3 distinctly larger than in lower 1/3th, the two types quite sharply separated. Vertex with both inner vertical seta broken off, apparently quite strong, no visible outer vertical, about ten long, slender postverticals slightly bend forward. Occiput with quite stout seta slightly bend forward. Ocellar seta hairlike, lateroclinate and slightly reclinate. Upper four frontal seta reclinate, other frontal seta crossed, the row descending towards base of pedicel, fronto-orbital plate and parafacial otherwise bare.

Antenna with pedicel twice as long as broad, first flagellomere 1.5 times as long as second. Arista thickened at basal quarter, second aristomere nearly twice as long as broad.

Thorax with 2 postpronotal setae, no obvious acrostichal setae, dorsocentrals 2+3, intraalar 1+2 (the anterior one placed outwards), a small first and a strong second supra-alar seta, the third lacking, 2-3 katepisternal setae accompanied by many long, stout, bristlelike hairs. Anepimeral seta not differentiated from adjacent hairs. Scutellum with three marginal setae of similar size, apical ones crossed; a much smaller fourth pair present near apicals. Lower calypter quite large, reaching to nearly halfway syntergite 1&2.

Excavation on syntergite 1&2 small, reaching only one quarter of syntergite. Syntergite 1&2 with a pair of strong central marginal setae and 1-2 pairs of lateral marginals, tergite 3 partly damaged but with several strong lateral marginal setae (so supposedly also central marginals), tergite 4 with a row of marginal; no discal setae present but hairs on all tergites erect. Sternites, except first, hidden by tergites.

Fore tibia with 2 small pd setae, claws and pulvilli slightly longer than apical tarsal segment. Mid tibia with a strong ventral seta, a strong ad seta accompanied by a second, much smaller one and 2 smaller posterior setae. Hind tibia with 3 av, 3 ad, 2 pd setae and 3 dorsal pre-apicals (pd, d and ad), coxa bare on backside, postmetacoxal area membranous.

Bend in vein M in wing gently curved, vein M reaching wing margin close to vein R 4+5 and close to apex of wing, hence cell r 4+5 open. Crossvein dm-cu distinctly closer to bend of vein M than to cross-vein r-m. Costal spine present, but small. First, second and basal half of third section of costa from below with small setulae. Base of vein R 4+5 with one long but slender seta.

Male genitalia: quite different from most other Tachinidae , but resembling those of Clairvillia biguttata ( TSCHORSNIG, 1985) : cerci fused to a syncercus, hook-shaped in lateral view, surstylus vestigial, pre- and postgonite fused, building a claw-like structure in lateral view ( Fig. 4 ). Epandrium elongated, in dorsal view 1.5 times as long as its basal width, in lateral view nearly twice as long as syncercus.

Length: 7 mm.

Female unknown.

E t y m o l o g y: niger, a Latin adjective, meaning ‘shiny black’, refers to the generally very shiny black habitus. Other known Palaearctic species have a pair of large red sidemarkings on the abdomen.

G e n e r i c a f f i l i a t i o n: Basedonthepresenceofonly2postintra-alar setae and the reclinate (though vestigial) ocellar seta, the species is placed within the tribe Leucostomatini . It is considered to belong to genus Clairvillia , despite the absence of red coloration on the tergites, which is present in other Palaearctic species of the genus. This is supported by the peculiar shaped united pre- and postgonites in male genitalia. Also, the sharply separated larger and smaller ommatidia in the eye are not seen in other Leucostomatini .

The new species differs from other black Leucostomatini by the lack of presutural acrostichals (present in Dionaea ROBINEAU- DESVOIDY, 1830 and Psalidoxena VILLENEUVE, 1941 ), the open cell r 4+5 (petiolated in Leucostoma MEIGEN, 1803 ), the number of katepisternal setae and slightly projecting vibrissal angle (only 2 katepisternal setae present and vibrissal angle not projecting in Clairvilliops MESNIL, 1959 ) and the membranous postmetacoxal area (sclerotized in both Clelimyia HERTING, 1981 and Takanoella Baranov, 1935 ). In the genus Labigastera Macquart, 1834 , the epandrium is enlarged and flattened, one pair of strong posterior acrostichal setae and distinct grey pruinescence on tergites is present.

Reduction of reddish sidemarkings in Tachinidae is not uncommon. In fact, the first author caught a male Clairvillia biguttata near Komsomolsk, Khabarovskii Krai, Russian Far East with strongly reduced reddish sidemarkings on tergites ( ZEEGERS 2017). The new species differs from such aberrant specimens of biguttata by its different male genitalia ( Fig. 4 ) and also by the reduction of the ocellar seta, the absence of a second ventral seta on mid tibia and the slightly more elongated abdomen ( Fig. 3 ).

Actually, the new species looks more similar to the western Nearctic Clairvillia nitoris (COQUILLETT, 1898) by sharing a shiny black elongated abdomen and reduced ocellar seta. The latter differs by the presence of the median light vitta on anterior part of thoracic dorsum and the yellow colouration of the palpus.

Figures

Fig. 2A-B: Male Clairvillia nigra nov.sp., holotype, habitus; (A) dorsal view; (B) lateral view. Scale bare = 1 mm.

Fig. 3A-B: Male Clairvillia, abdomen, dorsal view. (A) C. nigra nov.sp. holotype; (B) C. biguttata (male from Spain: Asturias). Scale bare = 0,5 mm.

Fig. 4A-B: Clairvillia male genitalia in lateral view. (A) C. nigra nov.sp., holotype; (B) C. biguttata (male from Greece, Peloponnesos). Scale bar = 0,1 mm.