Centrioncus Speiser, 1910

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

Genus Centrioncus Speiser, 1910

Centrioncus Speiser, 1910: 190; Frey 1925: 69; Duda 1925: 22, 24; Duda 1926: 110; Shillito 1950: 109; Smithers 1958: 25; van Bruggen 1961: 422; Steyskal 1970: 325; Griffiths 1972: 167; Feijen 1983: 4; Feijen 1989: 115; McAlpine 1997: 175, figs 21, 22, 35, 42; De Meyer 2004: 25; McAlpine 2011: 150, figs 122, 124; Feijen and Feijen 2021: 1535.

Type species.

Centrioncus prodiopsis Speiser, 1910: 191, by monotypy.

Remark.

Various papers from between 1925 and 1983 can refer to the second Centrioncinae genus Teloglabrus or a mixture of the two genera (see Feijen 1983).

Diagnosis of Centrioncus .

Updated version of the diagnosis by Feijen (1983). Centrioncinae with dark maxillary palps; dark section of funiculus limited to around base of arista; central region behind ocellar tubercle usually dark; wing with cell c partly or wholly glabrous, distal section of vein M4 gradually thinner, central wing spot present (Figs 1 - 8 ); on average 7-10 spinous setae per fore femur; basal ring of ♀ segment 7 with or without sutures; ♀ tergite 7 well sclerotised and with lateral edges curved under, ♀ sternite 7 split into a broad rectangular anterior plate and a curved or rectangular posterior plate (Figs 14 , 104 , 133 , 148 ); ♀ 7th spiracles in tergite or membrane; subanal plate large; epandrium broad and rounded with ratio width/length 1.4-1.5; inner arm of surstylus quite detached from common base of outer and median arms; surstylus in dorsal to dorsolateral position (due to inversion appearing ventrally); outer and median arms with patches of microtrichia on outer side; connection between surstylus and subepandrial clasper short; subepandrial clasper glabrous, without ridges, with 1-3 long setae and 2-8 short setae; inner posterior corner of epandrium without mesad extension for articulation with subepandrial clasper; articulation between subepandrial clasper and cercus via 1-2 small mesad sclerites, the sclerites of both sides linked via a membranous connection; ♂ cercus with distally a broad lateral extension or cercus slender; subepandrial sclerite anteriorly with large lateral extensions, w/l ratio 2.0-2.5; epandrial fold broad and short or epandrial sclerite present; hypandrial clasper with three terminal setae or absent; epiphallus well denticulated, lateral sides of phallophore distally acuminate, phallus rather broad, distal phallic sclerites large and U-shaped; ejaculatory apodeme + sac very large (9.2-16.3% of body length), proximal section of ejaculatory duct at right angles to ejaculatory apodeme.

Remark.

Centrioncus species are known from Angola, West Africa, and eastern Africa north of the Zambesi (north of 16°S latitude).

Figures

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 13 - 15. Centrioncus aberrans, Mount Elgon, ♀ 13 abdomen, ventral view 14 sternite 7, ventral view 15 spermathecae. Scale bars: 0.5 mm (13); 0.1 mm (14, 15).

Figures 101 - 105. Centrioncus crassifemur sp. nov., ♀, holotype, N'dalatando 101 sternites 1 - 5, ventral view 102 sternites 6 - 8, subanal plate, cerci, ventral view 103 tergites 8, 10, cerci, dorsal view 104 sternite 7, ventral view 105 subanal plate, ventral view. Scale bars: 0.5 mm (101, 102); 0.1 mm (103 - 105).

Figures 132 - 135. Centrioncus jacobae, ♀, paratype, Mt Soche 132 sternites 1 - 6, ventral view 133 sternite 7, ventral view 134 abdomen, ventral view 135 abdomen, dorsal view. Scale bars: 0.5 mm (132, 134, 135); 0.2 mm (133).

Figures 146 - 149. Centrioncus prodiopsis, ♀, Oloitokitok 146 sternites 1 - 6, ventral view 147, 148 sternite 7, ventral view 149 tergite 7 and cerci, posterolateral view. Scale bars: 0.5 mm (146); 0.1 mm (147 - 149).