Valiraptor vittatus, Londt, 2002

Londt, Jason G. H., 2002, Afrotropical Asilinae (Asilidae): A provisional key to genera, with a review of the status of Neomochtherus Osten Sacken, 1878, and descriptions of new genera and species, African Invertebrates 43, pp. 11-92 : 64-69

Valiraptor vittatus sp. n. ( Figs 244–248 )

Etymology: L. vitta – band or stripe, refers to the blackish longitudinal medial stripe of the mesonotum.

Diagnosis: Head: Antennal scape and pedicel yellowish; postpedicel longer than stylus. Thorax: Postpronotal lobe with long setae. Dorsocentrals posterior to transverse suture only. Microtrichial coverage of wing moderate in distal area (proximal tip of cell r 5 bare). Prothoracic femur with long, fine, hair-like posteroventral setae. Katatergal macrosetae mostly dark red-brown. Metathoracic coxa with one lateral macroseta; trochanter brownish yellow; femur anteriorly entirely yellowish or light brownish with dark red-brown to black macrosetae. Abdomen: Gonocoxite length:width ratio>2.5. Distal margin of S8 lacking medial process or sclerotised area. Ventromedial area of hypandrium not markedly constricted. Gonostylus moderately slender (viewed ventrally). Aedeagal terminal filaments well developed and filamentous. Gonostylus shorter than gonocoxite (viewed ventrally). Aedeagus strongly curved, greatly elongate and tubular. Epandrium simple (without obvious lobes or projections).

Material examined: Holotype: SOUTH AFRICA: 1ơ, ‘RSA Mpumalanga #91 / 16km North of Sabie / 25 ° [incorrect – 24 °]58'S: 30 ° 49'E 1350m / Date: 11.xii.1997 / Coll. JGH & A Londt / Forest Falls Trail’. Paratypes: SOUTH AFRICA: 1ơ, ‘ S Africa: E Transvaal / 11km W Sabi [Sabie] 2530BB / Lone Creek River / xii.5.1976 R Miller’; 1ơ, ‘ S Africa: N Transvaal / Entabeni For. Station / Zoutpansberg Range / Jan. 1975 Stuckenberg / indigenous for. 2230CC’ .

Type locality: South Africa, Mpumalanga, 16 km North of Sabie, Forest Falls Trail area .

Comments: A species readily separated from its congeners using the mesonotal stripe. It inhabits forested environments in the Limpopo and Mpumalanga provinces of South Africa ( Fig. 254 ) .

DISCUSSION Taxonomy

In an alpha-taxonomic study of this kind, there is often debate on what constitutes a genus. Tsacas (1969) in discussing afrotropical Neomochtherus species, observed that a number of species groups could be recognised. He took a conservative approach in deciding not to formalise such groups by giving them generic or even subgeneric status. Lehr (1996), on the other hand, chose to give Tsacas’ species groups generic status. My study confirms that there do indeed appear to be groups of species within this fauna, and so Neomochtherus sensu Tsacas (1969) must be seen as polyphyletic. To draw attention to this I have followed Lehr in according generic status to each identifiable group. It is, however, clear that many of the genera considered here are quite closely related and therefore difficult to define. Although Lehr (1996) emphasised characters of the male genitalia, he could not confidently delimit each of his taxa in terms of genital characteristics and no key was provided. While I have confirmed that species within the genera recognised in this paper do appear to have similarly developed genitalia, I too have had difficulty defining the groups on the basis of genital morphology. This is due to a number of limitations. For example, it is difficult to establish the degree of individual or geographic variation as large numbers of specimens would have to be dissected, and this would be unacceptably time-consuming. In addition, dissected material is difficult to interpret, as detailed morphological studies of the often tiny structures involved have yet to be undertaken. Not withstanding these considerations, I believe that my study has consolidated our understanding of the afrotropical Asilinae .

The status of some genera in the afrotropical asiline fauna needs further attention. The most pressing need is to establish the limits of Machimus in the light of the existence in the Natal Museum collection of a number of undescribed species which do not appear to conform to the currently accepted concept of this genus. Another useful project would be to establish the validity of Cerdistus in the afrotropical fauna. As this is primarily a palaearctic genus, the project would probably have to be part of a major work covering all known species, something one of my European colleagues might care to undertake.

Phenology, distribution and biology

Although little is known about the species reviewed and described in this paper, some general observations can be recorded. The phenology and broad distribution of the taxa are summarised in Tables 5 and 6 respectively. Afromochtherus: While data are limited for a few of the species, the adults appear to be mid-summer fliers – being recorded from September through to April,

with a single capture reported in June (Table 5). Most of the species (9) are recorded from southern Africa, while the others (4) are Central and East African

(Table 6). Personal experience suggests that species are ground inhabiting, or

Table 5

The phenology of asiline species studied in this paper. Abbreviations refer to months of the year.

Species J A S O N D J F M A M J Afromochtherus anatolicus - - - - • • - - - - - - astiptus - - - - - - - - • - - - atrox - - - - - - - - - - - - kolodrilus - - - - - • - - - - - - malawi - - - - - • - - - - - - megastylus - - - - - - - - - • - - melanurus - - - - • - • - • - - - mendax - - - • • • • • • - - • mkomazi - - • • • - • - - - - - peri - - • • • • • - - • - - sathus - - - • - - - - - - - - unctus - - - • • • - - - - - - zoropegus - - - - • • • - - - - - Aneomochtherus africanus - - - - - - • • - • • - deserticolus - - - - - - - - - - - - monobia - - - - • • • • • • - - Caenoura annulitarsis - - - - • • • • • • • - sinuatus - - - - - • • • • • - - Dikowmyia mediorus - - - - - - - - • - - - Gongromyia bulla - - - - - • - - - - - - Melouromyia diaphorus - - - - - - • - - - - - natalensis - - • - - • • • • • • • Notomochtherus brevicauda - - - - - • - - - - - Sphagomyia botswana - - - • • • - - - - - - kenya - - - • - - - - - - - - Tsacasiella blanda - • - - - - - - - • - - debilis • - - - - - - - - • - - exilis - - - - - - - - - - - • futilis - • - - • - - - - - • • inornata - - - - - - • • • • • - instabilis - - - - - - - • - • - - kivuensis - • - - - - - - - - - - neavei - - - - - - - - - • • - Valiraptor montanus - - - - - • • • • • - - namibiensis - - - - • - - - - - - - silvestris - - - • • • • • • • - - vittatus - - - - - • • - - - - - Species 1 3 3 8 13 16 16 10 11 14 6 4

Table 6 The distribution of asiline species studied in this paper. Abbreviations: Bo = Botswana; DC = Democratic Republic of the Congo; Ke = Kenya; Le = Lesotho; Ma = Malawi; Mo = Mozambique; Na = Namibia; Ru = Ruanda; SA = Republic of South Africa; Sw = Swaziland; Ta = Tanzania; Za = Zambia; Zi = Zimbabwe. Species SA Le Sw Na Bo Zi Za Mo Ma DC Ru Ta Ke Afromochtherus anatolicus • - - - - - - - - - - - - astiptus - - - • - - - - - - - - - atrox - - - - - - - - - • - - - kolodrilus • - - - - - - - - - - - - malawi - - - - - - - - • - - - - megastylus - - - • - - - - - - - - - melanurus • - - - - - - - - - - - - mendax • - - • - • - - - - - - - mkomazi - - - - - - - - - - - • - peri • - - - • • - - - - - - - sathus - - - - - • • - - - - - - unctus - - - - - - - - • - - • • zoropegus • - - - - - - - - - - - - Aneomochtherus africanus - - - - - - - - - - - • • deserticolus - - - - - - - - - - - • - monobia - - - - - - - - - - - • - Caenoura annulitarsis • • - - - • - - - - - - - sinuatus • - - - - • - - - - - - - Dikowmyia mediorus • - - - - - - - - - - - - Gongromyia bulla • - - - - - - - - - - - - Melouromyia diaphorus • - - - - - - - - - - - - natalensis • - • - • • - • • - - - - Notomochtherus brevicauda • - - - - - - - - - - - - Sphagomyia botswana • - - - • - - - - - - - - kenya - - - - - - - - - - - - • Tsacasiella blanda - - - - - - - - - • • - - debilis - - - - - - - - - • - - - exilis - - - - - - - - - • - - - futilis - - - - - - •? - - • - - • inornata - - - • • • - - • - - - - instabilis - - - - - - - - • • - - - kivuensis - - - - - - - - - • - - - neavei - - - - - - • - - - - - - Valiraptor montanus • - - - - - - - - - - - - namibiensis - - - • - - - - - - - - - silvestris • - - - - - - - - - - - - vittatus • - - - - - - - - - - - - Species 17 1 1 5 4 7 3 1 5 7 1 5 4

rest on stones (i.e. habitat categories 1a, 1c & 2b of Londt (1994)). The ovipositor is relatively short and broad when compared with related genera, and is probably adapted for depositing eggs directly into sand or soil. Four prey records are available, all for males of A. mendax – two hemiptera ( Alydidae &?Cicadelidae), two Diptera ( Mycetophilidae & Muscidae ).

Aneomochtherus : Adults are active between November and May and probably have their peak abundance in the later part of the southern hemisphere summer (bearing in mind that species live near the equator and that africanus straddles it) (Table 5). The known species are apparently confined to the East African countries of Tanzania and Kenya (Table 6). Little is known about the biology of this genus. Ovipositors are longish and somewhat laterally compressed, suggesting that species deposit their eggs into suitable places on plants (i.e. cracks in bark or in leaf axils). A. monobia apparently inhabits woodland and grassy areas, so an association with grass seems a strong possibility.

Caenoura : Adults are active between November and May, being most prevalent during the late summer months of January, February and March (Table 5). The two known species are confined to South Africa and Lesotho (Table 6). Personal experience indicates a strong association with grasslands – C. annulitarsis can be extremely common in open grasslands, while C. sinuatus is associated with the grassy margins of forest patches. The species can therefore be placed in category 4a of Londt’s (1994) classification of habitats occupied by asilids. The ovipositor of C. annulitarsis is clearly adapted for lodging eggs in crevices in vegetation, while that of C. sinuatus may allow eggs to be deposited directly into soil. Seven prey records are available – 6^ C. annulitarsis pinned with Lepidoptera (2 unidentified moths); three ant alates ( Hymenoptera : Formicidae ); two flies ( Diptera : Muscidae & Lonchaeidae ); 1^ C. sinuatus with a fly ( Diptera , Muscidae ).

Dikowmyia : The few specimens were captured in March (Table 5) in South Africa (Table 6). The only known species was captured in long grass in an open situation and so may also be placed in category 4a of Londt (1994). The ovipositor is intermediate between being short and conical, and long and laterally compressed, so oviposition behaviour is difficult to predict.

Gongromyia : The few known specimens were captured in December (Table 5) in South Africa (Table 6). They may have been collected from grassland, and the ovipositor could be adapted for laying eggs into plant crevices.

Melouromyia : The majority of records indicate that adults of the two known species are active during late summer (between December and June, there being a single record from September) (Table 5). While data for M. diaphorus are limited, M. natalensis is fairly widely distributed in southern Africa (Table 6) and also occurs in the Central African country of Malawi. M. natalensis has been collected from woody shrubs in suburban gardens in Pietermaritzburg, so may be classified as belonging to Londt’s (1994) category 5a or 5b. The ovipositor is long and laterally compressed, and therefore ideally adapted for oviposition in plants. Five prey records are available, all for M. natalensis females – flies ( Diptera : two Muscidae , Tipulidae , Asilidae ( Dasophrys sp. )) and a bug (Homoptera: Dictyopharidae ).

Notomochtherus : The few known specimens were captured in January (Table 5) in South Africa (Table 6). The only species known appears to be most closely related to Afromochtherus species. The ovipositor is of a similar design, and so the species may also inhabit open sandy areas and deposit eggs beneath the soil surface.

Sphagomyia: Although the two known species are apparently separated geographically by some distance, all known specimens were collected during October, November and December (i.e. early summer) (Table 5). P. botswana is found in the northern parts of southern Africa, while P. kenya is East African (Table 6). Most of the material from Botswana was collected in Malaise traps set in open woodland. Like Dikowmyia , the ovipositor is somewhat intermediate in development, but is probably used to deposit eggs into plant crevices.

Tsacasiella: Although data are limited, species appear to be late summer fliers – five of the eight species having been collected in April (Table 5). Apart from T. inornata , which has a distribution centred on southern Africa (but is also recorded from Malawi), all the species are Central African with one ( T. futilis ) also being recorded from East Africa (Table 6). Ovipositors are long and somewhat laterally compressed, and therefore probably adapted for laying eggs into plant crevices. The rather unusual, curved form of the ovipositor of T. futilis may be an adaptation for highly specialised oviposition behaviour.

Valiraptor : Species are active between October and April, thus having a mid to late summer flight period (Table 5). The species are confined to southern Africa, there being only one record from outside South Africa (Table 6). V. silvestris inhabits rank vegetation (including grass) adjacent to forests, while V. montanus is associated with montane grasslands.The ovipositors, being long and laterally compressed, are adapted for laying eggs in plant crevices. These species probably belong to Londt’s (1994) habitat categories 4 and 5. V. vittatus has been collected on low vegetation under a forest canopy. Eight prey records are available – V. silvestris 4ơ 3^ pinned with flies ( Diptera : Stratiomyidae , Calliphoridae , two Muscidae ); two moths (Lepidoptera: unidentified) and a beetle ( Coleoptera : Scarabaeidae ); and V. montanus 1^ pinned with an alate ant ( Hymenoptera : Formicidae ).

Seventeen (46 %) of the 37 species dealt with in this paper are known to occur in

South Africa. If the Central African genus Tsacasiella is excluded, South Africa would host 59 % of the species under review. This is a notable increase in species abundance considering that Tsacas (1969) reported a small number of specimens from South Africa,

representing only four species.

Figures

Figs 244–248. Valiraptor vittatus sp. n. (Sabi = Sabie ơ). 244. Antenna. 245. Wing. 246–248. ơ genitalia. 246. Lateral. 247. Dorsal. 248. Ventral. Scale lines = 1 mm.

Fig. 254. Distribution of Valiraptor species in southern Africa. V. montanus (circles), V. vittatus (squares).