Sisyrnodytes niveipilosus Ricardo, 1925

Londt, Jason G. H., 2009, A review of Afrotropical Sisyrnodytes Loew, 1856 (Diptera: Asilidae: Stenopogoninae), African Invertebrates 50 (1), pp. 137-137 : 163-165

Sisyrnodytes niveipilosus Ricardo, 1925

Figs 29, 30 , 41

Sisyrnodytes niveipilosus: Ricardo 1925: 247 ; Oldroyd 1957: 87; 1974: 74; 1980: 368 (catalogue); Hull

1962: 191 (figs 501 wing, 1031 & 1040 head).

Redescription:

Male (based on lectotype in excellent condition; both antennae broken off beyond pedicel, left prothoracic leg missing terminal four tarsomeres).

Head: Dark red-brown to black with white, orange and pale yellowish setae. Antennae: Brown-orange (terminal parts missing). Scape and pedicel white setose ventrally, yellowish dorsally. Major ventral setae of pedicel long. Eye to face width ratio 2.4:1. Mystax longish, white, fairly well developed dorsally. Frons and vertex white and orange setose; ocellar setae long. Laterally situated frontal setae orange and white, extending slightly below antennal sockets. Occipital setae white, postoculars mostly orange. Palps and proboscis yellowish setose.

Thorax: Dark red-brown to black. Pronotum white and yellow setose. Mesonotum distinctly humped, entirely long setose except for narrow paramedial strips, sutural and postsutural spots. Lateral macrosetae yellow-orange, other setae of similar development, mostly mixed white and pale orange, but there are clusters of uniformly white, brown or orange setae situated mainly anteriorly. Scutellum apruinose with poorly defined transverse groove (has crinkled appearance); disc asetose, apical marginal setae numerous pale yellowish and white. Pleural setae slightly wavy, mostly orange except for some white setae dorsally on anepisternum. Katepimeron orange setose, katatergals orange, long, shafts slightly wavy. Legs: Orange, proximal two-thirds of femora dark red-brown, mainly orange setose, but there are some small white setae too. Claws longish, dark red-brown to black; empodia yellowish, pulvilli minute to absent. Wings 7.0× 3.1 mm. C white setose basally; membrane transparent. Haltere yellow.

Abdomen: Dark red-brown to black; mainly long white setose except for anterior parts of T2–5 which have shorter yellowish setae.

Genitalia: Not dissected, but visible structures appear to conform to dissected and illustrated genitalia of a topotypic ơ from Bulawayo ( Figs 29, 30 ). Epandrium reduced in size and simple in structure, slightly bulbous proctiger extending well beyond it. Gonocoxite fairly large, external lobe tapering to fairly acute tip in lateral view, internal lobe long with down turned tip. Gonostylus fairly long, simple in structure. Hypandrium reduced, short and broad (twice as broad as long), transversely oval with broadly-rounded apex. Aedeagus robust, slightly dorsoventrally compressed, with wing-like projections laterally and rounded tip.

Female: Similar to male. Somewhat variable in setal coloration. Antennal setae white or yellow; mystax may be uniformly white, white dorsally and yellow to orange ventrally or white and yellow with some dark red-brown setae along epistomal margin (Namibian material); abdominal terga may be predominantly white setose or may have distinct bands of white and yellowish setae.

Variation: Wing length ơ 5.4–7.1 mm, ^5.1 –7.8 mm. Males, known only from Zimbabwean type locality demonstrate little variation. Topotypic male antennae red-brown; major ventral setae of pedicel longer than postpedicel.

Lectotype designation: Ricardo (1925) described the species on ‘ Paratypes (five females) from Bulawayo ( Rhodesia Museum ).’ Oldroyd (1957), under the heading ‘ Holotype ’, wrote ‘I do not think Miss Ricardo can seriously have meant to describe a species from paratypes only, without a holotype, and I imagine a line of text was omitted. There are specimens from Bulawayo in the British Museum , which are labelled “ paratype ^” in Miss Ricardo’s handwriting, but they are undoubtedly males. The best plan, no doubt, would be to consider them all as syntypes.’, and did not designate a lectotype. My experience suggests that all Ricardo’s newly described species, unless based on single specimens, are usually considered to be syntypes. I have studied only the single specimen listed above and here designate it as lectotype. The other four specimens mentioned by Ricardo I consider paralectotypes. Oldroyd (1974) stated ‘ Types in London and Bulawayo’, and Dr Erica McAlister confirms that, apart from the lectotype, there are three other cotypes at the BMNH. This means that the National Museum of Zimbabwe, Bulawayo, probably has a single paralectotype. While I have not checked the gender of all these specimens, Oldroyd (1957) was confident that they were all males and I accept his determinations. It is odd that Oldroyd failed to mention another two specimens, both females, in the BMNH (listed below) as these must surely have been available to him, when he reviewed the genus in 1957. He may not have been sure of their identification however, as the specimens do not carry his identification labels. The evident sexual dimorphism may have caused him some uncertainty .

Lectotype: ơ ZIMBABWE: ‘Pres. by / Imp. Bur. Ent. / Brit. Mus. / 1927–209.’, ‘ Sisyrnodytes / niveipilosus . / Ric.’, ‘ Bulawayo [20°09’S: 28°35’E] / S. Rhodesia / 20.5.1923 / Rhodesia / Museum’, ‘ Syntype / Sisyrnodytes / niveipilosus Ricardo / det. J.E. Chainey, 1983’ [this rectangular label has a circular blue rimmed label glued to its upper right hand corner reading ‘Syn- / type’] (BMNH). The specimen is double mounted on a cellulose strip and a little green verdigris is present above and below the specimen.

Other specimens examined: BOTSWANA: 1^‘ 20km W of Ghanzi , [21°34'S: 21°47'E] / Botswana / 28.viii.83. Day / C. Stockmann’ ( NMSA) ; 2^‘ N. Bechuanaland: / Ghanzi, / Mongaletsela. / 8.v.1924 / J. Maurice’ ( BMNH) ; 1^‘ Lekwabi Pan [?] / Bechuanaland / April 1960 / Schofield’ ( NMSA) ; 1^‘ Lekwabi Pan / Bechuanaland / iv 60 / Schofield’ ( NMSA) . NAMIBIA: 1^‘ Oshikango [17°24'S: 15°53'E] / Ovamboland / viii–48. Koch’ ( NMSA) ; 1^‘ Oshikango / C. Koch’ ( NMSA) ; 4^‘ Aminuis [23°43'S: 19°21'E] / SWA / SA Museum’ ~ ‘ Mus. Staff / June 1936 ’ ( SAMC) . SOUTH AFRICA: 1^Zoutpb. [Soutpansberg, 22°45'S: 30°00'E] dist. / 6-7.1917 / H. G. Breyer’ ( NMSA) ; 1^‘ 60m [?miles or km] W Hopetown, [29°37'S: 24°05'E] / C. Prov., S.Afr. / 8:iv:1961 / H. Dick Brown. ’ ( SANC) . ZIMBABWE: 2 ơ ‘ Bulawayo [20°09'S: 28°35'E] / 13.v.1923 / R. Stevenson’ ( NMSA) ; 1 ơ ‘ Bulawayo / S. Rhodesia / 6.6.1925 / R.H.R. Stevenson’ ( NMSA) ; 1^‘ Bulawayo / S. Rhodesia / 30.4.1927 / R.H.R. Stevenson’ ( NMSA) ; 1^‘ Bulawayo / 10.8.1918. / Rhodesia / Museum. ’ ( BMNH) ; 1 ơ ‘ Hillside / Bulawayo / S. Rhodesia / 13.5.1923 / Rhodesia / Museum’ ( SAMC) ; 1^‘ S. Rhodesia / Matopos Hills [20°35'S: 28°40'E] / iv.1932 ’, ‘ Miss A. Mackie’ ( BMNH) .

Distribution, phenology and biology: Oldroyd (1957) provided the following distributional information ‘ Southern Rhodesia [= Zimbabwe]: Bulawayo District, Northern Bechuanaland [= Botswana]: Ghanzi, Mongolatsela ( Maurice)’. An update was provided nearly twenty years later (Oldroyd 1974) ‘ Rhodesia: Bulawayo Dt., Matopos Hills. Botswana: Ghanzi, Mongolabela. Transvaal [then a province of South Africa]: Soutpansberg Dt.’ My study shows the species widely distributed over parts of Zimbabwe, Namibia, Botswana and South Africa ( Fig. 41 ). Adult activity was recorded as ‘April– May’ ( Oldroyd 1957) but my data show that specimens have been collected in April, May, June, July and August (i.e. autumn and winter) (Table 1). Labels provide no biological data.

Similar species: This species is distinctive and should not be confused with any other.

Figures

Figs 25–30. Sisyrnodytes species, ơ terminalia in lateral and ventral aspects: (25, 26) S. major Adams, 1905, Zuarungu, Ghana; (27, 28) S. nilicola (Rondani, 1850), Tel Aviv, Israel; (29, 30) S. niveipilosus Ricardo, 1925, Bulawayo, Zimbabwe. Arrowed is a broken structure. Scale lines = 1 mm.

Fig. 41. Distribution of Sisyrnodytes ausensis sp. n. (•), brevis (Macquart, 1838) (·) and niveipilosus Ricardo, 1925 (9).