Afrotropical Atrichops Verrall (Diptera, Athericidae) with description of a new species Author Muller, Burgert S. https://orcid.org/0000-0002-7304-4050 Department Terrestrial Invertebrates, National Museum, 36 Aliwal Street, Bloemfontein, 9301, South Africa & Department Zoology & Entomology, University of the Free State, P. O. Box 339, Bloemfontein, 9300, South Africa burgert.muller@nasmus.co.za Author Swart, Vaughn R. https://orcid.org/0000-0001-7905-5298 Department Zoology & Entomology, University of the Free State, P. O. Box 339, Bloemfontein, 9300, South Africa Author Snyman, Louwrens P. https://orcid.org/0000-0002-5768-7216 Invertebrate Zoology, Royal Alberta Museum, 9810 103 A Avenue NW, Edmonton, Alberta, T 5 J 0 G 2, Canada text African Invertebrates 2023 2023-12-11 64 3 303 322 http://dx.doi.org/10.3897/afrinvertebr.64.113133 journal article http://dx.doi.org/10.3897/afrinvertebr.64.113133 2305-2562-3-303 000F15D70DD746F7982625F13C43AF4C 1B4311FDBAF2573E8131BD435D38D7EF Atrichops adamastor (Stuckenberg, 1960) comb. nov. Figs 1 , 4 , 7 , 10 , 13 , 16 , 19 , 22 , 25 , 26 , 31 , 34 , 37 Atherix adamastor Stuckenberg, 1960: 273, fig. 86; Stuckenberg 1980 : 313; Nagatomi 1984a : 94. Identity. Stuckenberg (1960 : 273) originally described Atrichops adamastor in Atherix Meigen, noting that its wings are "unlike those of any other South African species". However, it also differs from all other described southern African athericid species by possessing the key diagnostic characters of Atrichops , namely a combination of a ventrally projecting knob-like proepimeral process (albeit much reduced), having the face narrower than the frons in female, and antennal bases closely set, nearly touching. It also has wing vein R4+5 setulose dorsally, a characteristic only present in Atrichops , compared to other Afrotropical genera (see Stuckenberg 2000 : 157). The male terminalia are also typical of Atrichops species, with the gonostylus inserted medially on the dorsal surface of the gonocoxite (e.g., Figs 31-33 ), compared to other genera where it is inserted apically. Atrichops adamastor has also been observed blood-feeding on frogs (see biology discussion below), a behaviour typical of the genus. Material examined. Type material examined (based on digital photos, additional data from Brinck and Rudebeck (1955 : 77)): Holotype : South Africa • 1♀ ; Western Cape Province , Cape Peninsula , Hout Bay , Skoorsteenkop ; [ 34°02.0684'S , 18°22.2420'E ]; [ 300 ft ]; 26 Dec. 1950 ; [ Swedish South African Expedition leg.]; No. 95, type no. 00790:1, MZLU00205685 (see Fig. 1 ) (MZLU). Figures 1-6. Atrichops spp. ♂ 1-3 lateral habitus 4-6 head anterior view 1 A. adamastor (BMSA(D)38908) 2 A. intermedius sp. nov. holotype (NMSA-Dip. 81808) 3 A. stuckenbergi (BMSA(D) 95848) 4 A. adamastor (BMSA(D)38904) 5 A. intermedius sp. nov. holotype (NMSA-Dip. 81808) 6 A. stuckenbergi (BMSA(D) 95848). Scale bars: 1 mm . Additional material examined. South Africa • 2♂ 10♀ ; Western Cape Province , Gamkaskloof (Die Hel) at:; 33°21.808'S , 21°37.650'E ; 336 m asl ; 16-18 Oct. 2012 ; Kirk-Spriggs, A.H. leg.; Malaise trap in Karoo and valley Acacia woodland; ( 2♂ : BMSA(D)38904, 38908; 10♀ : BMSA(D)38899, 38900, 38901, 38902, 38903, 38905, 38906, 38907, 38909, 40027) . Figures 7-12. Atrichops spp. ♀ 7-9 lateral habitus 10-12 head anterior view 7 A. adamastor holotype and specimen labels (MZLU 00205685) 8 A. intermedius sp. nov. paratype (NMSA-Dip. 81809) 9 A. stuckenbergi (CAS) 10 A. adamastor holotype (MZLU 00205685) 11 A. intermedius sp. nov. paratype (NMSA-Dip. 81809) 12 A. stuckenbergi (BMSA(D)95856). ( 7, 10 modified from originals provided by Rune Bygebjerg, MZLU, CC BY-NC 2.0 9, 12 modified from originals provided by Rikio Matsumoto, Osaka Museum of Natural History). Scale bars: 1 mm . Diagnosis. Atrichops adamastor can easily be distinguished from A. stuckenbergi . In A. adamastor the ommatrichia densely covers the eye in both sexes, the frons is dark brown, the face is brownish, and the wing is uniformly brown suffused, whereas A. stuckenbergi has the eye sparsely covered in ommatrichia, the frons is shiny black, the face has silver-white pruinosity, and its wing brown suffused mainly on apical half, with discal cell and cell m3 less so (e.g., Fig. 26 vs Fig. 30 ). It is most similar to A. intermedius sp. nov., a South African contemporary (see A. intermedius diagnosis). Remarks. The species was described by Stuckenberg (1960 : 273), based only on a single female. The description is sufficient and no re-description is necessary. A description of its previously undescribed (but known) male follows. Mention is made of female characters should they differ from the male. Description. Measurements (♂ n = 2, ♀ n = 10): Wing span: ♂ 4.8-5.2 mm (avg. 5.0 mm); ♀ 5.0-6.0 mm (avg. 5.4 mm); body length: ♂ 4.6 mm (avg. 4.6 mm); ♀ 3.7-4.9 mm (avg. 4.5 mm); wing span to body length ratio (avg.): ♂ 1.1; ♀ 1.2. Male. Head (Fig. 4 ): Colour brown, with some light yellowish pruinosity on face; eye densely covered in ommatrichia; narrowly dichoptic, ♀ widely dichoptic; ommatidia on lower 1/2 of eye smaller than upper 1/2 (♀ ommatidia uniform, comparatively larger than in ♂); lateral edge of eye with slight indentation, nearly absent in ♀; ocellar tubercle base level with frons, ♀ base with sunken appearance; ocellar tubercle with short dark setulae, vertex dark brown, almost appearing black, with somewhat longer setulae than ocellar tubercle; ocelli similar in size; ocellar tubercle in front of dorsal margin of eye, margin less indented than in ♀; vertex narrower than in ♀; dorsal inner edge of eye surrounding ocellar tubercle without discernible paired dark markings (present in ♀); occiput same dark brown as frons, when viewed at angle appearing shiny blackish; upper occiput with short dark setulae on dorsal margin and on rest of upper surface, lower occiput with erect, long and pale setulae, these continue ventrally on head to before mouthparts, bearing dark ventral setulae; frons dark brown, almost black, somewhat shiny, narrow area above antenna lighter brown; frons at narrowest as wide as anterior ocellus, widening towards antennal base, ♀ frons at least 2 x width of ocellar tubercle, narrowing only slightly towards antennal base (Fig. 10 ); frons with well-developed dark setulae on surface, but only on lateral margins, very similar to ocellar and vertical setulae; ♀ frons more setulose than ♂; face lateral edges bare; gena bare; face light brown, clypeus darker brown, ♀ clypeus orange-brown; clypeus bare; face separated from clypeus by prominent transverse suture, in ♀ separated by transverse emargination, never forming suture; clypeus less prominent than in ♀; face much wider than in ♀, with prominent longitudinal emargination on side of clypeus, giving appearance that face bulges laterally; face and clypeus not visible in profile (visible in ♀); antennal bases close together, almost touching, gap somewhat larger than in ♀; scape brown, dorsally infuscate around setulae; pedicel comparatively darker than scape, dorsal surface infuscate; scape and pedicel setulae dark; 1st flagellomere reniform, appearing almost 2 x height of pedicel, concolourous with pedicel, basal margins lighter brown; 2nd flagellomere arista-like, dark brown; scape and pedicel setulae similar in size; palpus dark brown, well-developed, ca 0.5 x length of proboscis, with long, dark setulae; proboscis dark brown with orange-brown base. Thorax (Figs 13 , 19 ): Scutum with short dark setulae, posterior setulae longer than anterior setulae; scutellum with well-developed dark setulae; postpronotal lobe lighter brown than scutum, with fine dark setulae; scutum uniformly dark brown; scutellum uniformly dark brown; pleura generally brown in colour, with anepisternum, katepisternum, anatergite and katatergite somewhat darker; proepimeron with reduced flap-like process near anterior edge; notopleuron with well-developed dark setulae; area surrounding posterior spiracle dark brown, postspiracular scale dark brown almost black; proepisternum and pronotum yellow; anterior spiracle bare posteriorly; proepimeron, proepisternum bare, anepisternum with short dark setulae; katatergite with long pale setulae; rest of pleura bare; postmetacoxal bridge narrow. Figures 13-18. Atrichops spp. ♂♀ dorsal view 13 ♂ A. adamastor (BMSA(D)38908) 14 ♂ A. intermedius sp. nov. holotype (NMSA-Dip. 81808) 15 ♂ A. stuckenbergi (BMSA(D)94158) 16 ♀ A. adamastor holotype (MZLU 00205685) 17 ♀ A. intermedius sp. nov. paratype (NMSA-Dip. 81809) 18 ♀ A. stuckenbergi holotype (CAS). ( 16 modified from original provided by Rune Bygebjerg, MZLU, CC BY-NC 2.0; 18 modified from original provided by Rikio Matsumoto, OMNH). Scale bars: 1 mm. Figures 19-24. Atrichops spp. ♂♀ proepimeral process, lateral view 19 ♂ A. adamastor (BMSA(D)38904) 20 ♂ A. intermedius sp. nov. paratype (NMSA-Dip. 81811) 21 ♂ A. stuckenbergi (BMSA(D)94158) 22 ♀ A. adamastor (BMSA(D)38899) 23 ♀ A. intermedius sp. nov. paratype (NMSA-Dip. 212861) 24 ♀ A. stuckenbergi holotype (CAS). ( 24 modified from original provided by Rikio Matsumoto, OMNH). Abbreviations: prepm - proepimeral process. Legs (Fig. 1 ): Coxae yellow, anterior surface of mid- and hind coxae brown; fore coxa with short dark setulae on surface, more pronounced apically; mid coxa with long dark setulae on surface, hind coxa with dark setulae on anterior and lateral apical edges, and with well-developed anterior apical point; trochanters with some scattered short dark setulae, trochanters yellow, apical margins with darker markings, more pronounced than in ♀; fore and mid femora, and basal 1/4 of hind femur yellow, apical 3/4 of hind femur dark brown (♀ with all femora yellow); fore, mid and hind femora with small anterior apical dark mark; fore, mid and hind tibiae dark brown (♀ with fore and mid tibiae yellow); all tarsi dark brown (♀ with yellow fore and mid tarsi); fore tarsal claws symmetrical, empodium at least 2 x size of pulvilli on fore legs; fore femur covered with dark setulae on all surfaces, posteroventral setulae forming row, mid femur with row of longer anteroventral setae and hind femur with similar dark setulae on ventral and dorsal surfaces; hind leg stouter than fore and mid legs; fore tibia and tarsi densely covered with long setulae along dorsal and ventral surfaces, at least as long or longer than width of segments (♀ without long hairs); hind tarsomeres 1.01-1.02 (♂) and 0.87-1.02 (♀) times as long as hind tibia. Wing (Fig. 25 ): Suffused brown on entire surface, with much darker pterostigma over area of veins R1 and R2+3 and cell r1 ; vein R4+5 with setulae dorsally, extending to vein R5 ; veins dark brown; cell br and discal cell uniform in colour; costa with distinct downward flexure over pterostigma; cell cua closed at short distance from wing margin, cell m3 open, veins M1 , M2 , M3 present; halter with yellow stalk and dark knob in both sexes and ♀ holotype (Fig. 7 ). This differs from original description of A. adamastor ♀ holotype with Stuckenberg (1960 : 274) noting "Halteres with pale yellowish knob." Abdomen : Dark brown, with anterodorsal margins of tergites 1-3 as well as entirety of sternites 1-5 yellow; tergites and sternites with short dark setulae, longer dark setulae on lateral margins of tergites, as well as long pale setulae on sternites 1-3; tergite 1 without median suture. Terminalia (Figs 31 , 34 ): Epandrium and cercus dark brown; hypoproct dark brown; epandrium, hypandrium and cercus with dark setulae; gonostylus finger-like with rounded apex; gonocoxite narrowing from middle towards base, apically rounded with long setulae; parameral apodeme long, extending to base of gonocoxite in ventral view; gonocoxal apodeme markedly shorter than gonocoxite. Female. Terminalia : Stuckenberg (1960) did not describe proepimeral process, which is reduced flap-like process (Fig. 22 ), much as in ♂. Cercus dark brown with dark setulae; genital fork (Fig. 37 ) with slender distal apodeme, median lobe with deep apical emargination, paired apical lobes with somewhat square appearance, arms each gradually rounded; 3 sclerotised, somewhat oblong, spermathecae. Distribution. South Africa (Western Cape Province). Biology. The species was observed and photographed feeding on the Cape River Frog, Amieta fuscigula Dumeril & Bibron in the Garden Route Botanical Garden, George, South Africa, by Colin Ralston (iNaturalist observation 9344668). While this behaviour has been informally observed before, it is the first published photographic observation of the species exhibiting typical Atrichops behaviour. It also emphasizes the importance of citizen science in highlighting species interactions that might otherwise go unrecorded or unnoticed. Although an attempt was made to sample material from the Botanical Garden for study, it was unsuccessful, possibly due to heavy rains earlier in the season.