Stylogaster occulta, Stuke, Jens-Hermann, 2015

Stuke, Jens-Hermann, 2015, New Conopid records from the Afrotropical Region (Diptera). Part 1: Paramyopa Kröber, Pseudoconops Camras, Stylogaster Macquart, Thecophora Rondani, and Zodion Latreille, Zootaxa 3963 (2), pp. 101-159 : 147-149

Stylogaster occulta spec. nov.

( Figs 107–113 )

Type material. Holotype ♂: (1) Congo Belge P. N. G. / Miss H. De Saeger / II/gd/11, 23–vi–1951 / Réc. J. Verschuren. 1969; (2) Holotypus / Stylogaster occulta / spec. nov. / det. Stuke, 2014. Paratypes. DEMOCRATIC REPUBLIC OF CONGO: 2♂, 6.viii.1948, Muyanoe (Imbo), 1600 m, leg. F. J. François, coll. ISNB; 3♂ with almost the same labels as holotype but third line with: II/le/8, 9–ix–1952 & 4040, II/fd/18, 26–vi–1951 & 1981, or II/ed/9, 22–vi–1951 & 1968. According to de Saeger (1956) these specimens were collected at Tète de souree boisée [4040], Strate herbeuse [1981], and Expansion marécageuse [1951]; BURUNDI: 1♂, 10.xi.1951, Rutana Province, Ghihofi-Moso, 1400 m, leg. F. J. François, coll. ISNB; 1♂, 11.xi.1951, ditto.

Holotype is deposited in the MRAC. Abdomen dissected, macerated and stored in glycerine in a microvial pinned beneath the specimen. The left hind leg and the right antenna are missing, and the holotype is otherwise in poor condition. The location is situated in the Garamba National Park (P. N. G.), Democratic Republic of Congo, Orientale Province. Additional information about the label was published in de Saeger (1956: 218): The specimen was collected at an Expansion marécageuse (wetland) [1969]. The paratypes are in the collection of MRAC and PJHS.

Description of holotype (male). Body length about 4.6 mm. Wing-length 3.9 mm. Head-height 1.2 mm. Head. Eye dark brown, with a few small scattered inconspicuous ommatrichia. Facets on inner side of eye slightly enlarged. Ocelli orange-brown. Ocellar tubercle dark brown, with 1 pair of inconspicuous ocellar setae. Ocellar triangle occupies almost the entire frons and reaches as far as antennae ( Fig. 107 ). Ocellar triangle brown. Frons brown lateral to ocellar triangle, with 3 proclinate fronto-orbital setae. Scape and pedicel yellowish brown, basal flagellomere brown with orange-brown base. Arista situated anterodorsally on basal flagellomere ( Fig. 108 —arista broken in holotype). Scape with a few brown setulae dorsally. Pedicel with black setulae dorsally and anteriorly. Basal flagellomere dorsally with a more shining surface than ventrally. Shape of antenna as illustrated in Fig. 108 . One distinct black vertical seta. Face pale yellow, silver pruinose. Postcranium black dorsally and yellow ventrally, distinctly silver pruinose. Postcranium with a line of regularly-arranged small white setulae. Some long brown setulae on mouth opening. Proboscis mainly brown to black, except for yellowish brown distal division of labellum and yellowish brown base of proboscis. Labrum ca 2.1 mm, labellum approximately the same length. Thorax. Yellowish brown to light brown, with scutum (with exception of postpronotum), scutellum and mediotergite dark brown. All setae black (several are broken in holotype). Two small notopleural setae, 1 strong supra-alar seta, 2 strong postalar setae, 1 prescutellar dorsocentral seta, 1 apical scutellar seta, 1 seta on anepimeron and 1 seta above fore coxa on propleuron. Black semi-adpressed hairs on scutum. Wing generally clothed in microtrichia, but bc, base of c, base of br, bm, base of dm and cup all virtually without microtrichia. Hind margin of wing with brown setulae. Venation as in Fig. 109 . Haltere orange-brown, distal part sharply defined dark brown. Legs whitish yellow, with brown hind femur. Legs with black and brown setae, fore tibia additionally with some white setulae. Fore and middle coxae with 1 brown to black seta. Hind coxa with 1–3 indistinct setae anteriorly. Hind trochanter with a small triangular tooth. Mid femur posteriorly in distal half with a row of regularly-arranged black setulae curved at their apices. Ventral side of mid femur lacking black erect setulae. All tibiae lacking conspicuous setulae. Hind tibia with short black spines on anterior surface. Claws yellowish brown basally, black distally. Pulvilli yellow to yellowish brown. Empodia short, pale brown. Abdomen. Pale brown, with tergite 1 brown, tergites 2–4 with brown posterior margin and broad brown median fascia, tergites 5–6 and epandrium largely dark brown. Tergites with semi-adpressed black setulae, and longer setulae laterally on tergite 5. Tergite 1 with long black setulae laterally, tergite 2 with black setae on either side of anterior margin. Terminalia as illustrated in Figs 110– 113 . Cercus short, slightly widened laterally, rounded distally. No teeth and only a few inconspicuous bristles at basal junction of cerci. Surstylus broad, with a finger-like process anterodorsally. Distal margin of surstylus lacking black tooth, but with a small field of erect setulae on inner surface. Two short membranous appendages on inner surface of surstylus directed from anterior margin backwards to the posterior margin. Phallus sheath as illustrated in Fig. 110 : Base of phallus sheath slightly protuding and covered with dense black spines.

Female unknown.

Variation (♂). Wing length 3.6–4.4 mm. Frons brown to black lateral to ocellar triangle, with 2–3 proclinate fronto-orbital setae. Antenna almost brown or with distinct orange-brown parts. Arista three-segmented. Scutum can be black. One notopleural bristle can be strong. Fore coxa may have two setae.

Etymology. From Latin occulta (meaning hidden, feminine) reflecting the misidentification as Stylogaster nitens in an earlier paper.

Discussion. Stylogaster occulta belongs to the Stylogaster nitens group as defined in the discussion of Stylogaster angolensis , the species of which can be identified using the key given above. Using Stuke (2012) the species will key out as Stylogaster nitens .

Distribution. Stylogaster occulta is known from the Democratic Republic of Congo and Burundi.

Figures

FIGURES 107 – 109. Stylogaster occulta spec. nov. (♂ paratype from 22 – vi – 1951). 107. Dorsal view of frons. 108. Lateral view of antenna. 109. Wing.

FIGURES 110 – 113. Stylogaster occulta spec. nov. (♂ holotype). 110. Lateral view of phallus sheath. 111. Dorsolateral view of cercus. 112. Lateral view of inner surface of surstylus. 113. Lateral view of outer surface of surstylus. mais—membranous appendage on inner surface of surstylus.