Sisyrnodytes dasykylon, Londt, 2009

Londt, Jason G. H., 2009, A review of Afrotropical Sisyrnodytes Loew, 1856 (Diptera: Asilidae: Stenopogoninae), African Invertebrates 50 (1), pp. 137-137 : 154-155

Sisyrnodytes dasykylon sp. n.

Figs 19, 20 , 43

Etymology: From Greek dasys (thick with hair, shaggy) and kylon (parts below eyes). Refers to the well-developed mystax that is supplemented by long frontal setae.

Redescription:

Male (based on holotype in excellent condition).

Head: Dark red-brown to black, with mainly white setose except for a few pale yellowish postocular setae. Antennae: Dark brown except for yellowish tip of style. Scape and pedicel white setose. Major ventral setae of pedicel project beyond level achieved by postpedicel. Basal element of style short (shorter than broad). Eye to face width ratio 1.8:1. Mystax longish, white. Frons and vertex white setose. Laterally situated frontal setae extending below antennal sockets, mingling with mystax. Occipital setae white. Some postoculars yellowish. Palps and proboscis white setose.

Thorax: Dark red-brown to black. Pronotum white and pale yellowish setose. Mesonotum extensively setose except for narrow paramedial strips and large sutural and postsutural areas. Lateral macrosetae white (npl) and yellowish (spal & pal), other setae white anteriorly, pale yellowish posteriorly. Scutellum apruinose with poorly defined transverse groove (has somewhat crinkled appearance); disc asetose, 20 pale yellowish apical setae (in single row). Pleural setae mostly white except for some yellowish setae dorsally on anepisternum and on katepimeron. Katatergals white, long, shafts more or less smooth. Legs: Dark red-brown, mainly white and pale yellow setose, but some black setae at apex of tibiae and ventrally on tarsi. Claws longish, dark red-brown; empodia moderately long, yellowish; pulvilli minute to absent. Wings 3.7× 1.5 mm, C white setose basally, membrane transparent. Haltere with orange-brown knob, dark brown stalk.

Abdomen: Dark red-brown to black, white setose. Tergal setae mostly long, reclinate laterally, short, rather transparent medially (giving the impression of asetose areas medially).

Genitalia: Not dissected, but visible structures appear to conform to dissected and illustrated topotypic ơ paratype ( Figs 19, 20 ). Epandrium moderately developed and simple in structure, proctiger not extending greatly beyond it. External lobe of gonocoxite in lateral view broadly rounded proximally, fairly acutely pointed distally. Internal lobe fairly robust. Gonostylus somewhat shorter than internal lobe of gonocoxite and simple in structure. Hypandrium flattish, sub-triangular in ventral view, with long gradually tapering medial lobe extending well beyond external lobe of gonocoxite. Aedeagus fairly slender with fairly blunt tip.

Female: Similar to male but have more yellowish setae which may even be described as orange in colour and in a few instances these outnumber white setae.A few specimens may even have some orange abdominal setae.

Variation: Wing length ơ 2.9–4.7 mm, ^3.2 –5.4 mm.

Holotype: ơ SOUTH AFRICA: Northern Cape: ‘ S Africa: Cape #33 / 23km SE of Middelpos / 32°01'S: 20°25'E 1200m / Date: 28.xi.1990 / Whittington & Londt / Banks of Visrivier’ ( NMSA).

Paratypes: SOUTH AFRICA: Northern Cape: 5 ơ 5^same data as holotype ( NMSA) . Western Cape: 6 ơ 14^‘ S Africa : Cape #21 / 70km E of Laingsburg / 33°06'S: 21°35'E 500m / Date: 24.xi.1990 / Whittington & Londt / Dry Dwyka River area’ ( NMSA, BMNH 1 ơ 1^) .

Other specimens examined: NAMIBIA: 2 ơ 1^‘ Gt Karas Mtns [Groot-Karasberge, 27°20'S: 18°45'E] / SWA / SA Museum’ ~ ‘ Mus. Staff / Nov 1936 (1939 ^) ’ ( SAMC) ; 2 ơ 2^‘ Gt. Fish R. / Aiais [27°55'S: 17°29'E], S. W.A. ’ ~ ‘ Mus. Staff / Nov. 1936 ’ ( SAMC) . SOUTH AFRICA: 4 ơ 6^‘ 26 mls [c. 41 km] North / of Postmasburg [28°19'S: 23°04'E]’ ~ ‘ Mus. Staff / Oct.1939 ’ ( SAMC) ; 1 ơ 4^‘ Kenhardt [29°30'S: 21°00'E] / Area’ ~ ‘ Mus. Staff / Oct. 1939 ’ ( SAMC) ; 5 ơ 4^‘ South Africa: N Cape / 1 km S Carnarvon 1260m / Appie van Heerden Nat. / Reserve 14.xi.2008 / 30°58.83'S: 22°07.39'E / J&A Londt Karoo scrub’ ( NMSA) ; 1 ơ ‘S Africa : Cape #34 / 2km N of Middelpos / 31°54'S: 20°14'E 1250m / Date: 29.xi.1990 / Londt & Whittington / Dry scrub on dam bank’ ( NMSA) ; 3 ơ 3^‘ South Africa: N Cape / Fish River bridge 23 km / SE Middelpos 1145 m / 32°01.42'S: 20°24.41'E / 18.xi.2008 J&A Londt / Sandy riverine scrub area’ ( NMSA) ; 2 ơ 1^‘ S.W. Africa: / Cape of Good Hope, / Nels Poort. [Research Station, 32°07'S: 23°00'E] / 2.xii.1933. / J. Ogilvie’ ( BMNH) ; 1^‘ S.W. Africa: / Cape of Good Hope, / Nels Poort. / 4.xii.1933. / J. Ogilvie’ ( BMNH) ; 5 ơ 2^‘ Sth Africa: Cape Prov / Gamka River 40km N / Prince Albert 3321BB / 11.xi.1986 500m / Londt & Quickelberge / Sandy area / Acacias’ ( NMSA) ; 1 ơ 1^‘ Gamkas Poort [33°19'S: 21°43'E] / Oct 1937 ’ ( SAMC) ; 1 ơ ‘ Cape Province / 43km ENE of Ceres [33°22'S: 19°19'E] on / road to Sutherland / 2-3.xii.1989 / F.W. & S.K. Gess’ ( AMGS) .

Distribution, phenology and biology: A fairly widely distributed species found in the Succulent Karoo and Nama-Karoo biomes of southern Africa ( Fig. 43 ). Adults have been collected during spring and summer (October–December) (Table 1). Experience tells me that the species is found in fairly arid, sandy places and that population densities may be low.

Similar species: This species is similar to nilicola and xeromyia .

Figures

Figs 19–24. Sisyrnodytes species, ơ terminalia: (19, 20) S. dasykylon sp. n., 23 km SE of Middelpos paratype, lateral and ventral; (21, 22) S. irwini Oldroyd, 1974, holotype, lateral (shape of robust aedeagus shown with a broken line) and ventral; (23, 24) S. major Adams, 1905, Nguruma, Kenya, lateral and ventral. Scale lines = 1 mm.

Fig. 43. Distribution of Sisyrnodytes curtus (Wiedemann, 1819) (•), dasykylon sp. n. (·) and oligotrichus sp. n. (9).