Two new species of Dactylonotus Parent , 1934 ( Diptera : Dolichopodidae ) from South Africa and a key to Afrotropical species

Two new species from South Africa, Dactylonotus nigricorpus sp. nov. and Dactylonotus tsitsikamma sp. nov., are described and illustrated. D. nigricorpus sp. nov. differs from all other species of the genus in the black body, the smaller size and the shorter antenna. D. tsitsikamma sp. nov. is peculiar in the genus in bearing a flag of long setae on the fifth segment of the fore tarsus. An identification key to 6 Afrotropical species of the genus is provided.


Material and methods
The holotypes of the new species are housed at the National Museum, Bloemfontein, South Africa (BMSA).They were studied with a ZEISS Discovery V12 stereo microscope and photographed with an AxioCam MRc5 camera.Morphological terminology and abbreviations follow Cumming & Wood (2009).Body length is measured from the base of the antenna to the tip of genital capsule.Wing length is measured from the base to the wing apex.Male genitalia were macerated in 10% KOH.The fi gures showing the hypopygium in lateral view (Figs 4,(10)(11)(12) are oriented as it appears on the intact specimen, with the morphologically ventral surface of the genitalia facing up, dorsal surface down, anterior end facing right and posterior end facing left.Genus Dactylonotus Parent, 1934Dactylonotus Parent, 1934: 136.

Diagnosis
The genus can be recognised by the fi nger-like projection or conus of the antennal pedicel, which overlaps the postpedicel dorsally in both sexes (Figs 2, 7); the postpedicel with distinct apex, with relatively short dorsal arista-like stylus, either median or subapical in position; the occiput convex or fl at; male frons and face broad; legs with an anterior preapical seta on the mid and hind femora; the wing costa extending beyond tip of R 4+5 , ending at apex of vein M; vein M unbroken (Figs 3,8); and male sternite 8 with strong projecting setae (Figs 4,10).

Remarks
Two species of the genus were formerly associated with the genera

Diagnosis
The new species is close to D. rudebecki Vanschuytbroeck, 1960 as described by Grichanov (1998) under the name D. meuffelsi, differing from the latter and all other species of the genus in the black body, smaller size, shorter antenna, the hypopygium morphology, the arista-like stylus apical, the mid femur without long setae, the simple tarsi with short claws and the small pulvilli.

Etymology
The species name is composed from Latin "niger" and "corpus" (black body). .

Type material
Holotype REPUBLIC OF SOUTH AFRICA: , Western Cape, Table Mountain  HEAD.Frons small, black, grey pollinose, with medial trapezoid depression, slightly prominent around base of antennae; face densely whitish pollinose, weakly narrowed in upper part, with parallel sides in lower part, 2 × as high as wide at clypeus; occiput fl at, black, grey pollinose; one pair of long ocellar and short postvertical setae; no vertical setae; postocular setae black in upper part and white in middle and lower parts of head; eyes with short white hairs; antennae (Fig. 2) inserted at upper fi fth of head, black, 2 × longer than height of head; scape long, microscopically haired; pedicel with long, slightly widened at apex, dorso-lateral (inner view) process, covered by dorsal, lateral and ventral setulae; postpedicel very long, widest at apex of pedicel, with acute apex, 3 × as long as high in middle, entirely covered by microscopic hairs; arista apical, with microscopic hairs.Length ratio of scape to pedicel to postpedicel (dorsal to ventral sides) to arista-like stylus (1 st and 2 nd segments) in mm, 0.27/0.40/0.49/0.74/0.05/0.32.Palpus and proboscis short, black, with black hairs.
THORAX.Mostly black, with black bristles; mesonotum weakly pollinose; pleura densely grey pollinose; metanotum brownish below; propleuron with 2 strong black setae in lower part; 6 pairs of dorsocentral bristles decreasing in size anteriorly, with several scattered hairs on anterior slope; acrostichals biseriate, extending to 5 th pair of dorsocentrals; scutellum with two long strong bristles and two short fi ne lateral setae, ¼ as long as medians, dorsally bare.

Female
Unknown.

Distribution
South Africa (Western Cape).

Diagnosis
The new species is close to D. univittatus (Loew, 1858) as described by Grichanov (2000), differing in the presence of the posterior brush of long setae on the fi fth segment of the fore tarsus, the brownish yellow hypopygium and the morphology of the hypopygial appendages.The arista-like stylus is middorsal; the fore coxa are with black hairs; the mid femur is without long hairs and setae.

Etymology
The species is named after the Tsitsikamma National Park in South Africa, where the type material was collected.ocellar and short postvertical setae; no vertical setae; postocular setae black in upper part and white in middle and lower parts of head; eyes with short white hairs; antennae (Figs 6-7) inserted at upper fourth of head, dirty-yellow, brownish dorsally and apically, 1.5 × longer than height of head; scape long, bare; pedicel long, slightly widened at apex, dorso-lateral (inner view) process, covered by dorsal, lateral and ventral setulae; postpedicel very long, widest at apex of pedicel, with narrow rounded apex, 2.8 × as long as high in middle, entirely covered by microscopic hairs; arista-like stylus middorsal, with short hairs.Length ratio of scape to pedicel to postpedicel (dorsal to ventral sides) to arista-like stylus (1 st and 2 nd segments) in mm, 0.33/0.38/0.40/0.73/0.43/0.60.Palpus and proboscis short, yellow, with black hairs.

Holotype
THORAX.Mostly brownish yellow, with black bristles; mesonotum with broad median metallic blue violet stripe embracing area between 2 nd -6 th pairs of dorsocentrals; scutellum dorsally blue-violet with yellow margin; pleura with a black spot below calypter; thoracic pollination weak; proepisternum with 2 long brownish ventral setae and 4 yellow hairs above; 6 pairs of dorsocentral bristles decreasing in size anteriorly, with several scattered hairs on anterior slope; acrostichals biseriate, extending to 5 th pair of dorsocentrals; scutellum with two long strong bristles and two short fi ne lateral setae, ¼ as long as medians, dorsally bare.

Female
Unknown.

Distribution
South Africa (Eastern Cape).

Discussion
Unfortunately, for each of the newly described species only one male was found despite intensive collecting with malaise trap and sweeping.Because the secondary sexual characters of these species (including the structure of their genitalia) are unique, their identifi cation will not be problematic in the future.Dactylonotus nigricorpus sp.nov. is the only species with a black body, whereas the other species have mainly yellow bodies.D. tsitsikamma sp.nov. is remarkable in the genus in bearing a fl ag of long setae on the fi fth segment of the fore tarsus.I think their descriptions are important due to our incomplete knowledge of the southern African dolichopodids and our poor understanding of the diaphorine genera.
The two new species and D. frater seem to be extremely rare in nature, all known by a single male only.Summarising my work with the genus over the last 20 years, I could fi nd 319 specimens of D. grandicornis, 37 specimens of D. univittatus and 9 specimens of D. rudebecki in the collections of dozens European and African museums.Thus, classical patterns of relative species abundance (e.g., McGill et al. 2007) are here confi rmed.Expanded knowledge of the genus will probably be essential to improve our understanding of the phylogenetic relations among diaphorine fl ies of the world.