Paragus cooksoni, 1998

Whittington, A. E., 1998, Hoverflies (Diptera: Syrphidae) from Vumba, Eastern Highlands of Zimbabwe, with the description of a new species of Paragus, Ann. Natal Mus. 39 (1), pp. 185-198 : 187-190

Type material: d Holotype: 'N.Vumba, I S.Rhodesia I 8.5. 1965 I D.Cookson.' [small rectangular white label, photographically produced, with date handwritten]; ' HOLOTYPE I Paragus I ( Pandasyopthalmus) I cooksoni sp.n. c 5 I Del. Whittington' Uarge rectangular red label with first and last lines printed, middle lines handwritten]. Deposited in NMSA.

Type locality: North Vumba [ca. 19° 06'S; 32° 46'E], Zimbabwe

Body length: 5.5 mm; wing length: 4.6 mm.

Description:

Head (Fig. 1): Eyes strongly developed and dominating (eye width five sixths of head width [Fig. 3; c/d = 0.81; eye width 0.6 of eye length [Fig. 3; cia = 0.6]); vestiture sparse and short. Face narrow in lateral view [Fig. 3; bid = O. U and in frontal view; orange-yellow. Buccal margin blackened at posterior end. Frons black, apical triangle densely white pruinose. Facial triangle (i.e. between constriction of eyes and insertion of antennae) minute and brown, covered with short white setae. Antennae grey-brown above, slightly redder ventrally. Width of third segment half its length. Sacculae organs numerous, small and scattered. Postocciput and postgena densely covered with thick white setae Thorax: Black with coarse punctation, each puncture with a seta. Vestiture on notum fine and golden, elsewhere short and white, but long, dense and white on anterior mesopleuron. Postalar callus and base of scutellar margin with wart-like tubercles giving rise to fine dark setae (Fig. 4). Legs reddish-brown; apex of femora and base of tibiae slightly more yellow. Mid-coxal prong well developed. Wings with microtrichia covering membrane; membrane suffused-brown; pterostigma elongate and brown. Veins brown. Brown spot present on vena spuria, a little beyond halfway along first basal cell. Calypter creamy-white, fringed with long, branched, white setae.

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Abdomen: Not conspicuously petiolate, second segment only fractionally narrower distally than proximally (Fig. 4). First segment with shining distal margin, free of setation. Second segment distinctly wider than long. Punctation pronounced, each puncture with a seta. Vestiture short, but slightly longer on proximal lateral edge.

Male postabdomen (Fig. 5): Epandrium saddle-shaped and longer than deep. Cerci rounded and narrow, weakly setose. Style narrow and tapering apically. Superior claspers rounded with a distinctive venterobasal spur (Fig. 5a). Penis-sheath about as deep as epandrium. Lingula strongly developed with medial groove strongly incised (Fig.5b).

Distribution: Known only from the type locality Discussion: For the sake of consistency, I have deliberately used the same terminology as that used by Stuckenberg (l954a), rather than that used more recently by Vockeroth & Thompson (1987).

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Paragus (P.) cooksoni clearly belongs to the longiventris -group of Pandasyopthalmus, having a flattened, non-tuberculate face and males without facial stripes. The abdomen is scarcely petiolate, but certainly not parallel-sided or diminishing distally, as is the case in the tibialis-group. The wings are suffused and covered with fine microtrichia and the frontal triangle is black, as in P. (P.) gracilis Stuckenberg, 1954 , although the abdomen is clearly different from that of P ( P) gracilis.

Aside from these gracilis-like characters, P (P) cooksoni most closely resembles P (P) minutus Hull, 1938. Both species share the following character states :

• No facial stripe in male

• No facial tubercle

• Pile on notum golden and very short (in cooksoni the pile is shorter than in minutus)

• Wart-like tubercles present on postalar callus and base of scutellar margin

• Punctation on thorax and abdomen coarse

• Abdomen only moderately constricted at base

• Second abdominal segment wider than long

• Well-developed superior claspers in male

In the keys to afrotropical species of Pandaysopthalmus ( Stuckenberg 1954a: 102-105), P (P) cooksoni runs to couplet 6 based on external features, and between couplets 6 and 7 based on male genital features. It differs from minutus in the following characters (character states of minutus in parentheses) :

• Eye large in comparison to head size, bId = 0.6, Figs 2 & 3 (smaller in comparison, bId = 0.5, Figs 2 & 3)

• Facial width narrow in comparison to head width, alc = 0.1, Figs 2 & 3 (wider in comparison, alc = 0.2, Figs 2 & 3)

• Length of third antennal segment twice the shorter dimension in lateral view (less than twice shorter dimension)

• Tergites 3 and 4 lack anterolateral wedge-shaped depressions filled with white setae (with wedge-shape depressions filled with white setae)

• Superior claspers in male rounded with a ventrobasal spur (boomerang-shaped, smooth along ventral margin)

• Style in male narrow and pointed towards apex (broad and dilated towards apex)

• Abdomen entirely black (with fifth tergite reddish)

Furthennore, there is close affinity between P ( P) cooksoni and P ( P) stuckenbergi De Meyer (1998); stuckenbergi differs from cooksoni in that the wing apex has a black spot, the hind tibia is curved, and the male postabdomen is substantially different. The superior claspers of stuckenbergi are narrow and curve downwards, and the lingula is broad and square with a shallow median groove, reminiscent of P ( P) marshalli Bezzi, 1915 .