Brachyradia, ík & Kjaerandsen, 2012
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publication ID |
https://doi.org/ 10.5281/zenodo.5347102 |
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persistent identifier |
https://treatment.plazi.org/id/AE078780-4C00-FF95-C063-FABEFF44FBA1 |
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treatment provided by |
Tatiana |
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scientific name |
Brachyradia |
| status |
gen. nov. |
Brachyradia View in CoL View at ENA , new genus
Type species. — Brachyradia asiatica View in CoL , new species
Gender. — Feminine
Etymology. — The generic name refers to the very short radial vein R 1 of the wing.
Diagnostic characters. — Small compact fungus gnats (body length 2–3 mm, wing length 1.3–2.1 mm) of the tribe Exechiini with mainly yellowish body ( Fig. 1A, B View Fig ), habitually similar to Brevicornu , Cordyla , and Neallodia but possessing a unique combination of modified wing venation, modified palps, shape of thoracic sclerites and terminalia. Wing vein R 1 very short ( Fig. 1D–F View Fig ), ending in costa in basal half of wing. Anepisternum ( Fig. 1C View Fig ) bare, subsquare with almost horizontal lower margin. Palpomere III ( Fig. 2A–E View Fig ) enlarged, forming a triangular shield over base of palpomere IV that is attached at the middle of the ventral surface. Tergite IX of male terminalia ( Figs. 2G View Fig , 3C View Fig , 4C View Fig ) strongly reduced, medially divided and devoid of setae. Female terminalia ( Figs. 3D View Fig , 4D View Fig ) short oviscapt, with two-segmented cercus.
Description. — Head ( Fig. 2A–C View Fig ) slightly elongated, subrectangular in frontal view. Compound eyes relatively small, covering about half of the length of head in lateral view. Lateral ocellus touching the eye margin, mid ocellus absent. Frons with several dark setae laterally in front of the ocelli, and several strong setae above the upper eye margin. Occipital furrow absent, frontal furrow short. Face short, with a few setae. Clypeus subrectangular to ovate, covered with short setae. Antenna ( Fig. 2F View Fig ) unmodified, about as long as head and thorax together; flagellum cylindrical with 14 short flagellomeres (F2 about as wide as long then gradually longer towards tip where F14 is 2 times as long as wide). Palp with 4 visible segments ( Fig. 2C View Fig ); palpomere I & II seemingly fused, palpomere III ( Fig. 2A, C–E View Fig ) enlarged, forming a triangular shield over base of palpomere IV that is attached at the middle of the ventral surface, sensory groove placed in basal half with opening on dorsal surface; palpomere V ( Fig. 2E View Fig ) longer than palpomere III+IV together.
Thorax ( Fig. 1C View Fig ) compact and somewhat dorsoventrally compressed; less highly arched than in most Exechiini . Scutum with small decumbent bristles intermingled among small setae, not arranged in distinct lines. Scutellum about as long as wide, its dorsal surface densely covered with dark setae, subapical bristles slightly longer than scutellum. Antepronotum and proepisternum with several dark setae, 3–5 proepisternal bristles. Anepisternum bare, subsquare with almost horizontal lower margin. Mediotergite and preepisternum 2 bare; ventral edge of preepisternum 2 convex, evenly rounded. Laterotergite with several dark bristles. Wing membrane covered with microtrichia in regular longitudinal rows; costa and R 4+5 with dorsal and ventral setae, radial stem and R 1 with dorsal setae only, other veins devoid of setae. Wing venation ( Fig. 1D–F View Fig ) modified: vein sc extremely short, vestigial and ending free; costa distinctly produced beyond R 4+5; vein R 1 very short, ending in costa less than half way from base of dmp to tip of wing; vein ta short, interrupted by a longitudinal fold; stem of M-fork short, 0.8–2.5 times as long as ta ( Fig. 1D–F View Fig ); Cu-fork branching slightly beyond branching of M-fork ( Fig. 1D–E View Fig ) or opposite to it ( Fig. 1F View Fig ); vein M 2 distinctly shortened, breaking between 2/3 and 3/4 its length before wing margin; CuP strong, apically weaker, reaching beyond the point of furcation of M; vein A 1 weak, short; A 2 distinct, not reaching wing margin. Legs covered with dark trichia and setae. All coxae with several black setae apically. Hind coxa in basal third with 2–3 fine dark posterolateral bristles. Femora laterally compressed, clothed with numerous dark trichia. All tibiae with numerous small trichia tending to form regular longitudinal rows and with several scattered short bristles. Fore tibia without any special tibial organ. One spur on fore tibia, about half as long as fore tibia; two spurs on both mid and hind tibia, ventral spurs slightly longer than dorsal ones. Hind tarsomere 1 with cluster of enlarged setulae ventrally at base (possibly a sensory organ operating together with spurs). Tarsal claws small, empodium absent.
Abdominal segments ( Fig. 1A, B View Fig ) with dark brown markings along posterior margins. Sternites narrow, with a more or less distinct medial concave fold longitudinally.
Male terminalia ( Figs. 2G, H View Fig , 3A–C View Fig , 4A–C View Fig ) small; tergite IX strongly reduced, medially divided, devoid of setae; proctiger enlarged, narrowly connected to tergite IX, cerci large, epiproct distinct, hypoproct large, downcurved, with pointed apex; gonocoxite ventrally with deep vshaped anterior emargination and wide shallow posteror emargination, open dorsally; hypandrial lobe well developed, bulbous; aedeagal guides retracted into gonocoxite; gonocoxal apodemes strongly sclerotized; aedeagal apparatus with pair of pointed parameres and apodemes connecting to gonocoxite. Gonostylus ( Figs. 3B View Fig , 4B View Fig ) with five distinct branches; dorsal branch large, lanceolate; dorsointernal branch bulbous, detached from dorsal branch, with a few strong setae; medial branch elongated, sclerotized, apically dilated, devoid of setae; ventral branch narrow elongated, with setae mostly confined to basal half; internal branch knob-like, with pair of strong setae apically; anterior branch vestigial or absent, striated internal cushion absent.
Female terminalia ( Figs. 3D View Fig , 4D View Fig ) short oviscapt, with tergite VII and IIX deeply retracted into segment VI; tergite VII small, with strongly sclerotized marginal sutures; cercus two-segmented, both segments short ovate; gonocoxite VIII with triangular apex in lateral view, apex with a few strong bristles; gonapophysis VIII thin, hyaline; gonapophysis IX triangularly tapered, sclerotized, with pair of small setae on tip.
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