Pseudorhyncomyia aethiopica, Rognes, Knut, 2013

Rognes, Knut, 2013, A new species in the genus Pseudorhyncomyia Peris, 1952 and the identity of P. deserticola Zumpt and Argo, 1978 (Diptera, Rhiniidae), Zootaxa 3736 (3), pp. 249-264 : 251-257

Genus Pseudorhyncomyia Peris

Pseudorhyncomyia Peris, 1952: 58 . Type species: Rhyncomyia braunsi Villeneuve, 1920 , by original designation. Pseudorhyncomyia: Zumpt 1958: 122 ; Pont 1980: 783.

This exclusively Afrotropical genus includes two valid species, i.e., Pseudorhyncomyia braunsi (Villeneuve, 1920) and P. aethiopica sp. nov. Pseudorhyncomyia braunsi is known from South Africa, Namibia and Tanzania (Pont 1980, Kurahashi & Kirk-Spriggs 2006) and has been described in detail by Peris (1952: 58) and Zumpt (1958: 122), the latter of whom selected a lectotype. Pseudorhyncomyia aethiopica is known from a single specimen from Ethiopia and is described below. The nominal species P. deserticola Zumpt and Argo, 1978 does not belong in this genus and is transferred to the genus Zumba Peris, 1951 , where it is a junior synonym of Z. antennalis (Villeneuve, 1929) (see separate section for this species, below).

Diagnosis. Rhiniidae with bare arista; normally developed mouthparts; anterior part of head not swollen; anteroposterior length of eye much larger than length of profrons in lateral view; parafrontal plate without strong frontal setae, but with numerous piliferous dots with short black setulae, these setae become larger towards frontal vitta and may be interpreted as very small frontal setae; lower part of parafacial and anterior part of gena each with a large black spot; lower facial margin shining black and shaped like a rounded strong protrusion; proepisternal depression bare; proepimeral setae absent; suprasquamal ridge posteriorly with a bundle of white setulae; meron without black setae, these replaced by long white setae in a few densely set rows; pleura covered by long densely set white setulae; wing cell r4+5 open or closed and petiolate; abdomen with mostly black ground colour, areas where yellow colour is shining through present anteriorly on dorsal side, dense white microtrichosity, numerous black piliferous dots and short black ground setulae dorsally; ventrally and anteriorly also with long white setae.

Description. Head. Male frons narrow, at narrowest point varying from a little narrower than anterior ocellus to twice as wide; i.e., a little narrower than ocellar triangle. Female frons at vertex about as wide as eye seen from above. Frontal vitta in both sexes reduced to a thin orange line, for most of its length narrower than the anterior ocellus (male) or about as wide (female), slightly widening out towards lunula. Lunula bare, shining dark brown to black ( P. braunsi ) or yellow ( P. aethiopica ). Antennal pedicel and first flagellomere black ( P. braunsi ) or yellow ( P. aethiopica ) in ground colour with a thin layer of microtomentum; first flagellomere 3 ( P. aethiopica ) or 4–5 times ( P. braunsi ) longer than wide. Arista bare, yellow basally, dark distally. Fronto-orbital plate with yellow ground colour; with white microtomentum; without strong frontal and orbital setae, with numerous piliferous dots each carrying a small black setula in center; these latter setae a little stronger near frontal vitta and may be considered to represent frontal setae. Parafacial with yellow ground colour, broad, with ( P. braunsi ) or without ( P. aethiopica ) microtrichosity, in latter case the parafacial is shining waxy yellow ( P. aethiopica ); a shining black spot present in lower part close to the eye, sometimes a shining glossy yellow spot in upper part of parafacial ( P. braunsi ). Facial membrane with yellow ground colour, with a thin layer of whitish microtomentum ( P. braunsi ) or bare and shiny waxy yellow ( P. aethiopica ). Lower facial margin a large rounded shining black protrusion, curved in a half-circle and rounded in anterior view, shining black, without ( P. aethiopica ) or with a wedge-shaped area of microtomentum ( P. braunsi ) on anterodorsal surface. Protrusion more pronounced in P. braunsi than in P. aethiopica . Gena in male one-third to one-fourth of eye height in profile view, in females ( P. braunsi only) almost one-half of eye-height (female P. braunsi ) in lateral view. Genal dilation with yellow ground colour, darkening towards hind end; posterior half microtrichose with small piliferous dots and long white densely set setae; anterior half shining waxy yellow ( P. aethiopica ) or with a thin layer of white microtrichosity sprinkled with large piliferous dots ( P. braunsi ); a black shining spot present in anterior part, close to eye margin. In one species ( P. aethiopica ) many of the white long setae on the posterior part of the genal dilation are yellow at the tip ( Figs. 3, 4 ). No black setae along lower edge of gena. Postgena with yellow ground colour, white microtrichosity and long white setae. Facial ridge broad, low, with yellow ground colour, shiny yellow ( P. aethiopica ) or with a thin layer of whitish microtrichosity ( P. braunsi ). A small black vibrissa present. No supravibrissal vestiture. No black subvibrissal setae, in P. braunsi a row of white subvibrissal setulae; in P. aethiopica no subvibrissal vestiture at all. The wedge-shaped area between anterior end of genal dilation and lower facial margin and below lower end of facial ridge yellow in ground colour, shiny yellow ( P. aethiopica ) or with thin layer of whitish microtrichosity with piliferous dots ( P. braunsi ). Mouthparts normal, mentum and palpus longer than antenna; mentum shining black. Palpus 3–4 ( P. aethiopica ) or 7–8 times ( P. braunsi ) longer than broad, yellow with slight microtomentum, slightly darkened apically ( P. aethiopica , female P. braunsi ), or dark in apical third (male P. braunsi ). Occipital region of head concave, black in ground colour except for the medial occipital sclerite which is yellow; white microtrichose all over the black area except for a black shining submarginal band without microtomentum, black occipital part also with white occipital setulae.

Thorax. Dorsum with black ground colour and white microtrichosity and numerous rather large piliferous dots. Five obscure vittae, the three medial ones partly microtrichose and reaching scutellum; the outermost vitta quite shining, without microtrichosity, and encompassing almost all of the notopleuron, the extreme upper part of the anepisternum and the outer half of the postpronotal lobe (humeral callus). Green bronze metallic ground colour shining through the microtrichosity. The anterior slope of prescutum, anterior surface of the postpronotal lobe, parts of notopleuron, postalar callus and lateral margin of scutellum with long white densely set often wavy setae; the remainder of the dorsum with short erect black or white very short setulae (male P. aethiopica , male P. braunsi ) or black obliquely set setulae (female P. braunsi ) originating from piliferous dots. In one species the white setae on the anterior slope of the thorax are yellow at the tip ( P. aethiopica ). White setulae also on underside of tip of scutellum. Suprasquamal ridge with white setulae in posterior part. Postalar wall bare. Pleura with black ground colour, with greenish or bronze metallic colouring hardly shining through the microtomentum, whitish microtrichosity and with small piliferous dots, carrying long white setae. Lateral surface of the postpronotal lobe, all of anepisternum, except for narrow area at uppermost part, posterior half of anepimeron, katepisternum and katepimeron with numerous, long, densely set white setae (in P. aethiopica some pleural setae with yellowish tips). Coxopleural streak present. Meron bare except for meral setae which are white and long. Metakatepisternum and katatergite bare. Proepisternal depression bare (very difficult to observe). Anterior thoracic spiracle yellowish, posterior thoracic spiracle yellowish brown ( P. aethiopica ) or brown ( P. braunsi ).

Chaetotaxy of black thoracic setae. Proepisternal and proepimeral setae absent. 0 prst acr ( P. aethiopica , female P. braunsi ) or 1 weak prst acr (male P. braunsi ). 1–2 post acr (the prescutellar). 0 prst dc (or 2 very inconspicuous ones?) + 1 post dc (the prescutellar) ( P. aethiopica ) or 2 weak prst dc + 1–2 post dc ( P. braunsi ). 0 prst ia (or 1 weak?) + 1 post ia ( P. aethiopica ) or 0 prst ia (or 2 weak on right side?) + 2 post ia ( P. braunsi ). 1 prst. 1 h (+ 1 very weak beside it) ( P. aethiopica ) or 2 h ( P. braunsi ). 1 inner and 1 outer ph (absent on right side) ( P. aethiopica ) or 1 inner and 1 outer ph strong ( P. braunsi ). The outer ph is very much to the outside of the prst. 2 npl, otherwise notopleuron with black ( P. aethiopica ) or black and white setulae ( P. braunsi ), short in females. 2 strong sa. 2 strong pa. Anepisternum with 1–2 upper and 1 lower black setae among the bundle of densely set long white anepisternal marginal setae, the short uppermost seta very close to the posterior notopleural seta. 1 + 1 kepst. Anepimeron without black setae. No black meral setae present, all are white and set in a couple of rows. Scutellum with three black marginal setae: apical, subapical and basal pairs; distance between subapicals almost the same as distance between subapical and basal ( P. aethiopica ; the P. braunsi female available has the tip of scutellum partly destroyed).

Wing. Tegula brownish-yellow, basicosta yellow. Subcostal sclerite yellow, without setulae, only with pale microtomentum. Veins yellow, darkening somewhat distally. No costal spine. Node at base of vein R2+3 and R4+5 bare below ( P. aethiopica ) or with 0–2 black setulae below ( P. braunsi ); with 1–2 black setulae above ( P. aethiopica ) or with 1–4 black setulae above ( P. braunsi ). Stem vein with 2–3 inconspicuous white setulae in P. aethiopica , 5–7 in P. braunsi . Cell r4+5 petiolate ( P. aethiopica ), or open ( P. braunsi ). Vein M with a very shallow curve ( P. aethiopica ) or more angulate ( P. braunsi ). Calypters white, lower one with inner edge diverging from axis of fly.

Legs. Shorter and stouter in P. aethiopica than in P. braunsi . Coxa, trochanter and femur with dark, tibia and tarsus with yellowish ground colour on all legs. White setulae on legs more numerous and shorter and thicker in P. aethiopica than in P. braunsi . Coxae and trochanters with numerous white setae. In P. aethiopica basal half or more of all femora with white setulae posteriorly, hind femur also with white setulae on anterior side. In P. braunsi long white hairs present on posterior side of fore femur; long white setulae present on posterior side of mid femur in male, but only a few short adpressed white setulae on posterior side of mid femur in female; and an ad row of white long setae along basal half of hind femur. Fore tibia with 0 ad and 1 pv ( P. aethiopica ) or with 4 ad and 1 pv ( P. braunsi ). Mid tibia with 1 ad, 1 p, 1 pv ( P. aethiopica ) or with 1 ad, 2–3 p, 1 pv, 1 v ( P. braunsi , both sexes). Hind tibia of P. aethiopica with few setae differentiated from rather strong ground setulae: 1 av and 1–2 pd visibly different. In P. braunsi the setae are much stronger: 1 av, 3–4 ad among a row of strong ad ground setulae, 3 pd.

Abdomen. The abdomen in both species dorsally and ventrally with large piliferous dots; dorsally more or less confluent, leaving a black mid-dorsal vitta bounded by densely white microtomentum of varying width. In P. aethiopica abdomen with one large yellowish spot dorsally on each side of midline affecting T1+2 and most of T3; in P. braunsi the yellow spots are confined to T1+2. T1+2 with black ground vestiture on most of dorsal surface; laterally with densely set white setae in several rows, among which are 3 black lateral discal setae in P. braunsi , but no discal setae in P. aethiopica ; ventrally with shorter and more sparse white vestiture. T3–T5 dorsally and laterally with short black setulae only, no white setae; with weak marginal setae, the ground setulae becoming stronger also along side of abdomen. Ventral surface of remaining tergites with black ground setulae and with additional white vestiture as follows: T3 ventrally with white setae on most of anterior half, posterior half with mostly black setae. T4 ventrally with white setulae along anterior third. T5 ventrally with white setulae along anterior margin. ST1 only with densely set white setae all over. ST2 with 2 strong erect black marginal setae in P. a e t h i o p i c a and numerous short white setae on disc; the black marginal setae are lacking in P. braunsi . ST 3 in P. aethiopica with 4 strong black marginal setae, a few smaller black and many white setae on disc; in P. braunsi ST3 with only extreme hind end visible, this part carries 2 black marginal setae. In P. aethiopica ST4 with 4 black marginal black setae, disc not visible. In P. braunsi ST4 not visible in the female examined, in the male the extreme hind end visible and carrying a pair of black setae. Male ST 5 in P. aethiopica with long yellowish lobes which carry a number of long white hairs, a few of which are yellow apically. Male ST 5 in P. braunsi with longer, greyish tomentose lobes with black setulae only. Female ST 5 in P. braunsi with 4 short black marginal setulae.

Genitalia. Male TST7+ 8 in P. aethiopica mostly lost, although a small fragment is still in place behind T5. The fragment is shining black with a slight greenish tinge, and has some microtrichosity on the left side. In P. braunsi TST7+8 is shining green metallic with numerous white setae except for a central area ( Fig. 26 ). Ovipositor with straight spines at tip, when known ( Fig.16 ).

Figures

FIGURES 3 – 9. Pseudorhyncomyia aethiopica sp. nov. (from holotype in NMSA). 3. Head, anterior view. 4. Head, left lateral view. 5. Head, dorsal view. 6. Right suprasquamal ridge, red arrow points to bundle of white setulae. 7. Original labels on holotype. 8. Apex of wing. 9. Area around meron and posterior thoracic spiracle on left side, red arrow points to white meral setae.

FIGURES 23 – 28. Pseudorhyncomyia braunsi (Villeneuve) (23, 25 – 27 from male in BMNH “ … Graaf Reinet … ”; 24, 28 from female in NMSA). 23. Right suprasquamal ridge. 24. Much of pleura and base of abdomen, left lateral view. 25. Apex of wing. 26. Tip of abdomen, ventral view. 27. Labels of male. 28. Labels of female.

FIGURES 14 – 16. Pseudorhyncomyia braunsi (Villeneuve) (from female in NMSA). 14. Habitus, left lateral view. 15. Habitus, dorsal view. 16. Abdominal tip. The reddish outgrowths on T 5 are fungi of the order Laboulbeniales, so far unidentified as to species.