Centrioncinae Hennig, 1965, 1862

Feijen, Hans R. & Feijen, Cobi, 2023, A revision of Centrioncus Speiser (Diptera, Diopsidae, Centrioncinae) with descriptions of new species from Angola, Burundi, and Kenya, ZooKeys 1144, pp. 1-93 : 1

Subfamily Centrioncinae Hennig, 1965

Centrioncinae : Hennig, 1965: 62; Shillito 1971: 288; Steyskal 1972: 1; Feijen 1983: 67 (as Centrioncidae ); Feijen 1989: 115 [as Centrioncidae ]; McAlpine 1997: 170; Hilger 2000: 335; Meier and Hilger 2000: 1, 6; Baker et al. 2001: 89; Meier and Baker 2002: 332; Nartshuk 2003: 246 [as Centrioncidae ]; De Meyer 2004: 25; Kotrba and Balke 2006: 843; Kotrba et al. 2010: 299; McAlpine 2011: 150; Feijen and Feijen 2021: 1523.

Type genus.

Centrioncus Speiser, 1910: 190.

Diagnosis of Centrioncinae .

Updated version of the diagnosis by Feijen (1989) for Centrioncidae . Small (4-7 mm), slender flies; head rounded (Fig. 11 ); eyes not stalked; pedicellus without cleft and in lateral view strongly asymmetrical; funiculus (=first flagellomere) ventrally extended within sagittal plane ~ 1.7 × the width of pedicellus, funiculus with a large basal hollow on dorsal half, into which the strongly asymmetrical pedicellar conus is inserted; tripartite pubescent arista; one pair of outer vertical setae and one pair of fronto-orbital setae; lanceolate basiliform prosternum (Fig. 129 ); supra-alar ridge (carina) present; no pleurotergal spines, three pairs of scutal setae, one pair of scutellar spines with apical setae (Fig. 117 ), apical setae varying from 20% shorter to 25% longer than spines; costa unbroken, alula present (Figs 1 - 8 ), veins CuA+CuP and M4 reaching margin, impression of crossvein bm-cu visible, wings transparent with or without vague spots; incrassate fore femora with double series of ventral tubercles and spinous setae; slender hind femora with distal set of small tubercles; no apical spurs on mid and hind femora; syntergite consisting of tergites 1 and 2; ♀ segment 7 sclerotised basally in complete ring, ♀ sternite 7 transversely divided, ♀ tergite 8 and sternite 8 each consisting of two sclerites; ♂ tergite 6 half as long as tergite 5, main part of ♂ sternite 7 located on left side, very large inverted ♂ sternite 8 (Fig. 136 ) on both sides fused to sternite 7 which forms a complete ventral band of sclerotisation ( Feijen and Feijen 2021: fig. 38); abdominal spiracles 1-6 in membrane, ♀ 7th spiracles in tergite or not, ♂ left 7th spiracle in laterally located sternite 7 and ♂ right 7th spiracle in ventral band of sclerotisation; three (2 + 1) spermathecae; elongate, striated eggs; articulated three-lobed surstylus with tubercles and often spinous setae; subepandrial sclerite with clasper-like ventral lobes and large mesal plate; membranous ♂ cercus; small phallapodeme with posterior two-thirds fused to hypandrium, hypandrial clasper usually present; postgonites and epiphallus present, phallus a short solid structure with a complex distal section; ejaculatory apodeme + sac present, seminal ducts without distinct reticulated transverse structures.

Figures

Figure 117. Centrioncus decoronotus, ♂, Nyahururu, Ngare Naro Forest. Photograph by D. Gavryushin.

Figures 9 - 12. Centrioncus aberrans 9 Mount Elgon, ♀, habitus, lateral view 10 - 12 Timboroa Forest, ♂ 10 head, dorsal view 11 head, frontal view 12 thorax, lateral view. Arrows indicate glossy spots on frons. Scale bars: 0.5 mm.

Figures 126 - 131. Centrioncus jacobae, paratypes 126 Mt Ndirande 127 - 131 Mt Soche 126 ♂, habitus, lateral view 127 ♀, thorax, dorsal view 128 ♂, head, anterolateral view 129 ♀, basiliform prosternum, ventral view 130 ♀, fore femur, inner view 131 ♂, hind femur, inner view. Scale bars: 0.5 mm (126 - 128); 0.2 mm (129 - 131).

Figures 1 - 4. Centrioncus, dorsal view of wings 1 ♂, C. aberrans, Timboroa Forest 2 ♀, paratype, C. bururiensis sp. nov., Bururi Nat. Forest 3 ♂ C. bytebieri, Ngangao Forest 4 ♀, paratype, C. copelandi sp. nov., Kasigau Mtn. Scale bars: 0.5 mm.

Figures 5 - 8. Centrioncus, dorsal view of wings 5 ♀, holotype, C. crassifemur sp. nov., N'dalatando 6 ♂, C. decoronotus Njuki-Ini Forest 7 ♂, C. jacobae Mount Soche 8 ♀, C. prodiopsis, Oloitokitok. Scale bars: 0.5 mm.

Figures 136 - 138. Centrioncus jacobae, ♂, Mt Soche 136 holotype, abdomen, hind femur, lateral view 137 epandrium, surstyli, posterior view 138 paratype, subepandrial clasper and surstylus, inner view. Scale bars: 0.5 mm (136); 0.1 mm (137, 138).