Sisyrnodytes xeromyia, Londt, 2009

Londt, Jason G. H., 2009, A review of Afrotropical Sisyrnodytes Loew, 1856 (Diptera: Asilidae: Stenopogoninae), African Invertebrates 50 (1), pp. 137-137 : 169-170

Sisyrnodytes xeromyia sp. n.

Figs 37, 38 , 42

Etymology: From Greek xeros (dry) and myia (fly). Refers to the generally arid area from which specimens are known.

Redescription:

Male (based on holotype in excellent condition).

Head: Dark red-brown to black, white and yellowish setose. Antennae: Dark brown except for tip of style which is yellowish. Scape and pedicel white setose. Major ventral setae of pedicel project beyond level achieved by postpedicel. Basal element of style short (slightly longer than broad). Eye to face width ratio 2.1:1. Mystax longish (especially dorsally), white. Frons and vertex white setose. Laterally situated frontal setae extending below antennal sockets. Occipital setae white, postoculars white except for some yellowish setae behind ocellar tubercle. Palps and proboscis white setose.

Thorax: Dark red-brown to black. Pronotum yellow and white setose. Mesonotum entirely longish white and yellowish setose except for narrow paramedial strips, sutural and postsutural spots. Lateral macrosetae white; other setae mostly white with patches of yellowish setae (anteriorly and adjacent to sutural and postsutural spots).Scutellum apruinose with moderately well-defined transverse groove; disc asetose, apical setae numerous white (slender and somewhat wavy except for 8 more robust setae). Pleural setae mostly white except for some yellowish setae dorsally on anepisternum.Katepimeron wavy yellow setose, katatergals white, long, somewhat wavy shafts. Legs: Orange-brown, femora dark red-brown except for orange-brown distal ends, mainly white setose, some blackish setae distally on metathoracic tibiae and ventrally on all tarsi. Claws longish, dark red-brown; empodia yellowish; pulvilli minute to absent.Wings 4.8×2.0 mm; C white setose basally; membrane transparent. Haltere with orange knob, brown stalk.

Abdomen: Dark red-brown to blackish, terga white setose, sterna pale yellowish setose. Tergal setae long, mostly erect laterally, shorter, reclinate along posterior parts (weak, transparent anteriorly).

Genitalia ( Figs 37, 38 ): Epandrium greatly reduced and simple in structure, proctiger projecting well beyond it. Gonocoxite with external lobe tapering to blunt tip, internal lobe clearly visible in lateral view, with hook-like tip. Gonostylus fairly long, tapering to longish filamentous tip. Hypandrium with broadly oval (in ventral view) proximal region and somewhat club-shaped distomedial lobe. Aedeagus fairly slender with blunt tip.

Female: Similar to male, but males generally more extensively white setose and setae are longer than in females which have more yellowish setae. Abdominal terga usually have orange setae anteriorly (one has red-brown setae) and white setae posteriorly.

Variation: Wing length ơ 4.8–5.4 mm (– x= 5.1 mm, n=5), ^4.2 –7.0 mm (– x= 5.3 mm, n=9); males slightly smaller than females. There is little geographical variation (the Botswana male has pale yellow setae on the posterior parts of the mesonotum).

Holotype: NAMIBIA: ơ ‘ Namibia 24.iv.1983 / 20km W Usakos [22°00'S: 15°35'E] 2115CD / Londt & Stuckenberg / Sparse savannah’ ( NMSA).

Paratypes (all NMSA): BOTSWANA: 1 ơ ‘ Tzatonie Pan / Botswana / 15.6.69 2322CD / T. Schofield’ . NAMIBIA: 1^same data as holotype; 1 ơ 1^‘ Oshikango [17°24'S: 15°53'E] / Ovamboland / vii.48. Koch’; 1^‘ Oshikango O- / vambold. [Ovamboland] vii / 1948. C. Koch’; 1 ơ 1^‘ Oshikango / Ovamboland / viii.48. Koch’; 1^‘ Namibia 22.iv.1983 / 48km W of Windhoek / 2116 DA Stuckenberg / & Londt Thornveld in / dry river valley’; 4^‘ Namibia 18.iv.1983 / 5km S Windhoek 2117CA / Londt & Stuckenberg / Mixed Thornveld’; 1 ơ ‘ Valencia [?] S. W.A. / 4/6/1972 / A.F. Port’ .

Distribution, phenology and biology: Known only from northern Namibia and western Botswana ( Fig. 42 ).Adults have been collected from April through to August (no record for May) (Table 1) and so fly during autumn and winter in an area receiving late summer rainfall. Little is known of the biology, but I have collected the species in sparse savannah and thornveld.

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

Figures

Figs 31–38. Sisyrnodytes species, ơ terminalia in lateral and ventral aspects: (31, 32) S. oligotrichus sp. n., holotype; (33, 34) S. subater Oldroyd, 1957, Serowe; (35, 36) S. vestitus Oldroyd, 1974, Gemsbok Pan paratype; (37, 38) S. xeromyia sp. n., holotype. Scale lines = 1 mm.

Fig. 42. Distribution of Sisyrnodytes apicalis Oldroyd, 1957 (•), subater Oldroyd, 1957 (·) and xeromyia sp. n. (9).