Scelolabes Philippi, 1865

Barros, Luana Machado, Freitas-Silva, Rafael Augusto Pinheiro de & Ale-Rocha, Rosaly, 2023, Revision of Neotropical Scelolabes Philippi (Diptera, Hybotidae, Ocydromiinae): two new species and a proposal of delimitation, European Journal of Taxonomy 890 (1), pp. 49-70 : 51-52

Genus Scelolabes Philippi, 1865

Scelolabes Philippi, 1865: 751 , pl. 28 fig. 45

Scelolabes – Gerstaecker 1867: 415 (diagnosis). — Schiner 1868: 200 (citation). — Bigot 1889: 116 (in key). — Bezzi 1905: 458 (catalogue). — Kertész 1909: 104 (catalogue). — Melander 1928: 49 (citation), 51 (in key), 71 (catalogue). — Edwards & Shannon 1927: 655 (citation). — Collin 1928: 13 (citation); 1933: 3 – 4 (citation), 9 (key), 47 (citation), 49 (remark). — Hardy 1930: 238 (citation), 239 (table), 248 (in key). — Smith 1967: 16 (catalogue). — Chvála 1983: 111, 226 (citation). — Plant 1989: 231 (citation). — Sinclair & Cumming 2000: 179 (citation), 182 (in key, world distribution); 2006: 78 (citation); 2007: 37 (citation). — Camousseight 2005: 90 (list). — Ale-Rocha 2007: 410 (citation and in key). — Yang et al. 2007: 335 (catalogue). — Ale-Rocha & Freitas-Silva 2014a: 442 (in key); 2014b: 502 (citation). — Barros et al. 2019: 399 (citation); 2022: 516 (citation). — González et al. 2021a: 163 (list), 166 (catalogue).

Scelobates (sic) – Reed 1888: 301 (catalogue). — Bezzi 1905: 458 (correction). — Melander 1902: 250 (citation). — Becker 1915: 155 (citation).

Scelolates (sic) – González & Llanos 2019: 121 (list).

Type species

Scelolabes bivittatus Philippi, 1865 , by monotypy.

Revised diagnosis

Antenna inserted above mid height of head ( Fig. 3A ). Prosternum narrow, acrostichal multiserial ( Fig. 3F ), 1 notopleural seta. Hind tibia without apical strong process, usually with outstanding short setae ( Fig. 5E ). Discal cell short (shorter than length of bm cell) ( Fig. 3G ), CuA vein complete or incomplete. Hypandrium with a short projection on right distal margin with a tuft of long and slender setae ( Fig. 4A ); right surstylus with bifid apex, chela-like ( Figs 2F , 4F , 6F ); female tergite 10 absent, sternite 10 subtriangular, divided medially ( Fig. 4G ).

Redescription

Male

COLOUR. Predominantly yellow species.

HEAD. Eyes bare. All ocellar facets uniformly sized. Frons shining, except lower half with pruinosity, narrower than width of anterior ocellus; very close eyes near face. Antenna inserted above mid height of head ( Fig. 3A ), postpedicel lanceolate, about twice length of scape and pedicel combined, covered with dense microtrichia ( Fig. 5C ); two pairs of ocellar setae proclinate, anterior pair strong and long, posterior pair very short and thin. Proboscis oriented downwards, short; palpus covered with setae. Occiput covered with pruinosity ( Figs 1E , 3E ), postocular setae elongated, scattered, upper setae stronger ( Fig. 3E ).

THORAX. Prosternum narrow (not forming precoxal bridge).Acrostichal setulae multiserial, dorsocentrals uniserial, short, slender and sparse on scutum. Notopleuron with 1 seta; lacking postpronotal seta; 1 anterior long and strong as well as 1 posterior short and slender postalar setae. Scutellum with 1 pair of lateral setae and 1 pair apical of bristles.

WING ( Fig. 1G ). Narrow, not enlarged at apex. Membrane pale brown; pterostigma present, elongate and narrow, situated at apex of c cell; basal costal seta present, strong; Rs short, arising near apex of br cell; R 1 vein long, ending at apical ⅓ of wing; dm cell shorter than basal cells; CuA vein complete or incomplete, reaching or not reaching CuP vein; CuA+CuP not reaching wing margin; M 1+2 and M 4 veins reaching wing margin; anal lobe not developed. Halter with a row of spine-like setulae on stem ( Fig. 1C ).

LEGS. Fore and mid legs slender; hind femur slightly to strongly swollen, banded near apex. Chaetotaxy of legs: hind tibia without apical strong process, only a slender dorsal outstanding seta at apex. Tarsi lacking outstanding bristles.

ABDOMEN ( Fig. 1A, H ). Shining. Syntergite 1+2 partly fused. All tergites weakly sclerotized anteriorly. Sternite weakly sclerotized. All tergites covered with short to long and slender setae on apical margin.

MALE TERMINALIA ( Fig. 4A–F ). Hypandrium with slender setae, and a short projection on right distal margin with a tuft of long and slender setae ( Fig. 4A ). Phallus elongate, phallic shaft gradually arched, cylindrical, without protuberances ( Fig. 4C–D ); phallus articulation as long as phallic shaft, sclerotized. Left epandrial lamella slightly shorter than right lamella ( Fig. 4C ); right epandrial lamella with a dorsal projection near base ( Figs 2B , 4B , 6B ); dorsal connection between epandrial lamellae wide and narrow ( Fig. 4B ). Surstyli setulose, setae inserted on tiny tubercles ( Fig. 4F ); left surstylus usually sinuous at apex ( Fig. 4E ); right surstylus shorter than left, with bifid apex, chela-like ( Fig. 4F ). Cerci symmetrical, short, subtriangular, weakly sclerotized, flattened, covered with short and slender setae ( Fig. 4B ); subepandrial sclerite short and broad, with basal margin truncate and distal margin with slight medial concavity; hypoproct with short marginal apical projections ( Fig. 4B ); bacilliform sclerite setulose.

Female ( Fig. 3B )

Similar to male, except by the shorter length.

FEMALE TERMINALIA ( Fig. 4G ). Tergite and sternite 8 fused laterally, broad; sternite 8 with slight constriction in posterior margin making a bifid and sharpened projection. Tergite 10 absent. Sternite 10 slightly sclerotized, small, sub triangular, divided medially. Cerci symmetrical, slightly sclerotized, flattened, short, covered by several short and slender setae.

Distribution

Scelolabes is known from southern Argentina and Chile. Sinclair & Cumming (2000) also list the genus from Australia.

Remarks

Scelolabes is similar to Hoplopeza by the antenna inserted above the mid-height of the head, wing with anal lobe not developed and Rs vein very short, arising near the apex of bm cell. Both genera are different by apical strong setae in hind tibia present in Hoplopeza , vs weak or absent in Scelolabes , right surstylus with bifid apex, chela-like in Scelolabes , vs simple in Hoplopeza , and tergite 10 absent in females of Scelolabes , while it is present in Hoplopeza . Additionally, in Scelolabes the acrostichal setae are always multiserial, while in Hoplopeza they may be either uniserial or multiserial.

Figures

Fig. 3. Scelolabes bivittatus Philippi, 1865 (INPA). A–B. Lateral habitus A. Male. B. Female. C. Halter, row of spine-like setulae in evidence. D. Antenna of male in lateral view. E. Occiput of male in dorsal view. F. Scutum of male in dorsal view. G. Wing of male. H. Abdomen of male in dorsal view.

Fig. 5. Scelolabes verasilvae sp. nov. A, C–G. Holotype, ♂ (CNC). B. Paratype, ♀ (CNC). A. Lateral habitus. B. Lateral habitus of female. C. Antenna in lateral view. D. Scutum in dorsal view. E. Hind legs. F. Abdomen in dorsal view. G. Wing. Fig. 5B provided by Bradley Sinclair.

Fig. 4. Scelolabes bivittatus Philippi, 1865. A–F. Male terminalia. A. Ventral view. B. Dorsal view. C. Left lateral view. D. Right lateral view. E–F. Surstyli in frontal view. E. Left. F. Right. G. Female terminalia in ventral view. Scale bars = 0.1 mm.

Fig. 2. Scelolabes amorimi sp. nov. A–F. Male terminalia. A. Ventral view. B. Dorsal view. C. Left lateral view. D. Right lateral view. E–F. Surstyli in frontal view. E. Left. F. Right. G. Female terminalia in ventral view. Abbreviations: bac scl = bacilliform sclerite; cerc = cercus; epand = epandrium; hypd = hypandrium; hyprct = hypoproct; ph = phallus; projc = projection; sbepand scl = subepandrial sclerite; st = sternite; sur = surstylus. Scale bars = 0.1 mm.

Fig. 6. Scelolabes verasilvae sp. nov., male terminalia. A. Ventral view. B. Dorsal view. C. Left lateral view. D. Right lateral view. E–F. Surstyli in frontal view. E. Left. F. Right. Scale bars = 0.1 mm.

Fig. 1. Scelolabes amorimi sp. nov. A. Holotype, ♂ (MNHN). B. Paratype, ♀ (MNHN). C–H. Paratypes (MNHN). A–B. Lateral habitus. C. Halter, row of spine-like setulae in evidence (arrow). D. Antenna in lateral view. E. Occiput of male in dorsal view. F. Scutum in dorsal view. G. Wing of male paratype. H. Abdomen in lateral view. Abbreviations: bm = basal medial cell; br = basal radial cell; CuA = anterior branch of cubital vein; cua = anterior cubital cell; CuA+CuP = anterior branch of cubital vein + posterior branch of cubital vein; dm = discal medial cell; M 1+2 = first branch of media; M 4 = fourth branch of media; R1 = anterior branch of radius; R2+3 = second branch of radius; R4+5 = third branch of radius; Rs = radial sector.