Dactylolabis (Dactylolabis) kyororo, Kato, 2023

Kato, Daichi, 2023, Taxonomic study of the genus Dactylolabis Osten Sacken, 1860 of Japan (Diptera: Limoniidae), Zootaxa 5375 (2), pp. 227-240 : 232-234

Dactylolabis (Dactylolabis) kyororo sp. nov.

( Figs 3 , 6A )

Diagnosis. Grey to dark brownish grey species with sparsely patterned wing. Antenna generally brownish black, 1.7–2 times length of head. Thorax generally grey to dark grey, with four darker thoracic stripes. Wing brownish tinged, yellowish on base, with small or narrow darkening at origin of Rs, R 2, along cord and CuA. Legs with femora to tarsi dark brown except yellow femoral bases. Hypopygium with epandrium cylindrical, about as long as wide. Gonocoxite 2.2 times as long as wide and about as long as epandrium. Outer gonostylus roughly finger-shaped, slightly shorter than gonocoxite and inner gonostylus. Interbase with middle part broadened into squarish plate, bearing distinct U-shaped notch at middle of posterior margin. Aedeagus cylindrical, straight, tip extending slightly beyond posterior end of interbase.

Type material. HOLOTYPE, male, JAPAN, Honshu, Niigata, Tokamachi-shi, Matsunoyama , Echigo-Matsunoyama Museum of Natural Science , ‘ Kyororo’ , altitude 310 m, N37.0995°, E138.6163°, 16–23.V.2021, D. Kato, MT ( BLKU) . PARATYPES: JAPAN: [Honshu] 1 male, same data as holotype except 14. V .2023 ; 1 male, Niigata, Shibata-shi, Takidani, altitude 204 m, N37.8155°, E139.4629°, 11. V .2022 , D. Kato ( BLKU).

Description. Male. Body length 8.1–9.0 mm, wing length 8.0– 9.3 mm.

Head. Grey, weakly tinged with brown on posterolateral part of vertex, sparsely covered with yellow and dark brown setae. Anterior part of vertex with narrowest part relatively broad, 4/3 as wide as eye in dorsal view; vertex posterior to eye slightly longer than eye. Antenna generally brownish black, 1.7–2 times length of head. Scape dark grey, 3.5 times as long as wide. Pedicel slightly greyish, twice longer than wide and about half as long as scape, distal part distinctly broader. Flagellomere oval to long oval, 2–3 times length of width on flagellomere 1, gradually decreased in size toward apical segment; each segment with about seven verticils, at most as long as corresponding segment, and covered with pale pubescence, about 1/4 length of corresponding segment; pubescence on apical flagellomere indistinct. Rostrum 3/4 length of scape. Palpus dark brown; palpomere 1 small, roundish; palpomeres 2–5 almost same in length, each segment three times as long as palpomere 1; palpomere 4 slightly broader than other segments. Labellum dark brown.

Thorax. Notum weakly subnitidous by relatively sparse pruinosity, sparsely covered with short yellow to brown setae. Pronotum grey, with or without brownish longitudinal line at middle; postpronotum vaguely brownish laterally. Mesonotum generally grey; prescutum and presutural scutum tinged with ocherous except lateral margin, with four darker stripes, middle pair well-separated on anterior part in anterodorsal view, extending from near anterior end to near transverse suture; lateral pair broader and shorter, about half length of middle one, reaching at transverse suture and joining dark marking on scutal lobes; scutal lobe with large brown area at middle, narrow posteriorly. Scutellum weakly brownish. Mediotergite distinctly dark on posterior half in dorsal view. Pleuron dark grey, dorsopleural membrane pale yellowish. Wing ( Fig. 3B ) tinged with brown, prearcular region yellowish. Obscure small darkening present at origin of Rs and R 2, one at crossvein sc-r and near fork of R 2+3+4 absent in one paratype; CuA and cord seamed with brown, one on CuA more distinct, one on A 1 and outer end of cell dm indistinctly dark. Rs strongly curved near base; cell dm 2.8 times as long as wide. Legs covered with short blackish setae. Coxae grey, posteroapical surface of fore coxa brownish. Trochanters brown to dark brown. Succeeding segments dark brown, basal 1/3 of femora gradually turning into yellow toward bases. Halter whitish yellow.

Abdomen. Dark brownish grey, sparsely covered with yellowish setae.

Hypopygium ( Figs 3C–I ). Epandrium ( Fig. 3C ) cylindrical, about as long as wide. Hypandrium ( Fig. 3D ) strongly and widely convex posteriorly at middle of posterior margin. Proctiger ( Fig. 3C ) roughly squarish, lateral lobe ( Fig. 3E ) roughly tongue-shaped, weakly pointed at tip, twice as long as wide. Gonocoxite ( Fig. 3F ) 2.2 times as long as wide, and 0.9–1 times as long as epandrium, slender, widest on basal and distal 1/3. Outer gonostylus ( Fig. 3G ) roughly finger-shaped, gradually narrowing to tip, slightly shorter than gonocoxite and inner gonostylus, slightly wider than inner gonostylus; inner gonostylus ( Fig. 3G ) curved and flattened on distal 1/3, tip rounded. Interbase ( Figs 3H–I ) with middle part fused and forming wide, squarish plate, bearing pair of small triangular ventral lobes, gradually narrowed to tip; posterior margin of interbase with distinct U-shaped notch at middle; lateral arm curved medially and abruptly narrowed on distal 1/3. Paramere ( Figs 3H–I ) slender, weakly curved outward. Aedeagus ( Figs 3H–I ) cylindrical, relatively slender, straight, tip extending slightly beyond posterior end of interbase. Sperm pump ( Figs 3H–I ) large, slightly shorter than and about five times as wide as aedeagus, with small nail-shaped plate covering middle of ventral end. Ejaculatory apodeme ( Figs 3H–I ) with each arm large and wide, directing anteroventrally.

Female. Unknown.

Distribution. Japan (Honshu) ( Fig. 6A ).

Etymology. This new species is named after the type locality, Echigo-Matsunoyama Museum of Natural Science, ‘Kyororo’, where it was found for the first time. The specific name is a noun in nominative singular.

Remarks. This species is generally somewhat similar to the previous species, D. (D.) diluta , and the morphological differences are shown in the key to species above.

Figures

FIGURE 3. Dactylolabis (Dactylolabis) kyororo sp. nov. A. habitus, lateral view; B. wing; C. hypopygium, dorsal view; D. male hypandrium, ventral view; E. lateral lobe of proctiger, outer surface; F. gonocoxite, outer view; G. gonostyli, dorsal surface. H. aedeagal complex, dorsal view. I. same, lateral view (left side directing dorsally). Scale bars: A, 3 mm; C–I, 0.1 mm.

FIGURE 6. Distributions of Japanese species of Dactylolabis. A. D. (D.) diluta (red circle) and D. (D.) kyororo sp. nov. (green square); B. D. (D.) longicauda.