Sisyrnodytes aethes, Londt, 2009

Londt, Jason G. H., 2009, A review of Afrotropical Sisyrnodytes Loew, 1856 (Diptera: Asilidae: Stenopogoninae), African Invertebrates 50 (1), pp. 137-137 : 142-143

Sisyrnodytes aethes sp. n.

Figs 5–7 , 44

Etymology: From Greek aethes (unusual, strange). Refers to the unusual wing venation that represents a condition intermediate between that found in Acnephalum and that characteristic of all other species of Sisyrnodytes .

Description:

Male.

Head: Dark red-brown to black with yellow, white and pale orange setae. Antennae: Orange except for slightly paler tip of style. Scape and pedicel pale yellow-white setose. Major ventral setae of pedicel project beyond level achieved by postpedicel. Basal element of style long (twice as long as broad). Eye to face width ratio 2.7:1. Mystax moderately long, yellow-white. Frons and vertex yellow-white setose. Laterally situated frontal setae not extending below antennal sockets. Occipital setae white, postoculars orange dorsally. Palps and proboscis dark red-brown, white setose.

Thorax: Dark red-brown to black. Pronotum white, pale yellow and orange setose. Mesonotum entirely pale yellow setose, but asetose centrally (probably through abrasion). Scutellum apruinose with poorly defined transverse groove; disc asetose, apical setae numerous (difficult to count) pale yellowish. Pleural setae long, glistening whitish. Katepimeron strongly setose, katatergals long, shafts more or less smooth (i.e. not wavy). Legs: Orange, mainly white and pale yellow setose (there are some dark red-brown to black setae distally on tibiae and ventrally on tarsi). Claws longish, dark red-brown to black; empodia short yellowish; pulvilli minute to absent. Wings c. 7.8 (tip missing) × 3.5 mm; C white setose basally; membrane transparent but slightly pale yellowish stained anterobasally. Venation unusual with C not terminating at the wing tip but continues around it, ending slightly beyond where M 2 reaches wing margin (as in Fig. 5 ). In addition veins M 3 +CuA 1 and CuA 2 +A 1 reach wing margin. Haltere brown-yellow with reddish knob.

Abdomen: Dark red-brown, glistening white setose; setae long laterally and along posterior margins of terga.

Genitalia ( Figs 6, 7 ): Epandrium greatly reduced and simple in structure, proctiger extending well beyond it. Gonocoxite with external lobe tapering to blunt tip, internal lobe with slightly inflated distal tip. Gonostylus shorter than internal lobe of gonocoxite and simple in structure. Hypandrium flattish, triangular in ventral view, with medial lobe extending almost as far as tip of internal lobe of gonocoxite.Aedeagus fairly slender with small, blunt tip.

Female: Agrees with male except as follows. Generally more yellow and orange setose. Prothorax mostly orange setose; mesonotum anteriorly orange and posteriorly yellow setose.Apical scutellar setae not as numerous (c. 30). Legs orange-brown. Wing ( Fig. 5 ) length 6.6 mm; venation as in male, but C ends where M 2 reaches wing margin (not slightly beyond that point as in male). Abdominal setae shorter.

Holotype: ơ SOUTH AFRICA: Northern Cape: ‘Soebatsfon- / tein [30°07'S: 17°35'E] 13–14.11 [xi]’ [19]33 / G. van Son’ ( NMSA). The holotype is in fair condition, somewhat greasy, right antenna broken off beyond pedicel, left wing broken off at midlength.

Paratype: SOUTH AFRICA: Western Cape: 1^‘ Sth Africa : Cape Prov / Meiringspoort 3323CA / 12.xii.1979 Londt / & B. Stuckenberg Rocky / hillside & stream edge’ ( NMSA) .

Distribution, phenology and biology: Recorded only from two fairly widely separated localities in the winter-rainfall region of South Africa ( Fig. 44 ).Adults active in November and December (Table 1). The female paratype was collected on sandy ground near a stream flowing through the Meiringspoort and was found together with brevis .

Similar species: This is a distinctive species, differing from congeners in having costal vein continuing around wing tip and terminating where M 2 reaches wing margin.

Figures

Figs 1–5. Sisyrnodytes species: (1) S. brevis (Macquart, 1838), dorsal view of a Gonnemanskraal ơ; (2) S. curtus (Wiedemann, 1819), lateral view of Knersvlakte ^; (3, 4) S. major Adams, 1905, variation in wing staining: (3) Nguruma ơ; (4) Azare paratype ơ; (5) S. aethes sp. n., wing venation of Meiringspoort paratype ^.

Figs 6–12. Sisyrnodytes species, ơ terminalia: (6, 7) S. aethes sp. n., holotype, lateral and ventral (position of aedeagus faintly stippled); (8, 9) S. apicalis Oldroyd, 1957, Strandfontein, lateral and ventral; (10–12) S. aterrimus Engel, 1929, Bulawayo paratype: (10) lateral, (11) oblique view of gonocoxite, (12) ventral.Abbreviations: aed – aedeagus, el – exterior lobe of gonocoxite, epan – epandrium, goncx – gonocoxite, gonst – gonostylus, hypd – hypandrium, il – interior lobe of gonocoxite, proct – proctiger. Scale lines = 1 mm.

Fig. 44. Distribution of Sisyrnodytes aethes sp. n. (•), irwini Oldroyd, 1974 (·) and vestitus Oldroyd, 1974 (9).