Stylogaster ivindoensis, 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 : 139-140

Stylogaster ivindoensis spec. nov.

( Figs 82–91 )

Type material. Holotype ♂: (1) 0030′44′′N / 1246′12′′E / GABON: Ogoou-Ivindo / Ivindo NP, Makokou (518 m) / 11.–19.IX.2012, An Pfad im / nahe Station / (Malaisetrap 3), leg. R. Peters; (2) Holotypus / Stylogaster ivindoensis / spec. nov. / det. Stuke, 2014.

Holotype is deposited in the ZFMK. Abdomen dissected, macerated and stored in glycerine in a microvial pinned beneath the specimen. The left fore leg, the right fore tarsus and the right middle tibia are missing. The holotype is otherwise in good condition.

Description of holotype (male). Body length about 8.9 mm. Wing-length 6.8 mm. Head-height 2.1 mm. Head. Eye dark brown, without ommatrichia. Facets on inner side of eye slightly enlarged. Ocelli orange-brown. Ocellar tubercle black, with 1 pair of inconspicuous ocellar setae. Ocellar triangle occupies almost the entire frons and reaches as far as antennae ( Fig. 83 ). Ocellar triangle dark brown brown, lighter medially. Frons orange-brown to black lateral to ocellar triangle, and with 1–2 proclinate fronto-orbital setae. Antenna yellowish brown, only basal flagellomere dark dorsally. Arista situated anterodorsally on basal flagellomere, three segmented, black ( Fig. 84 ). Scape with a few black setulae anterodorsally. Pedicel with black setulae dorsally and ventrally. Shape of antenna as illustrated in Fig. 84 . 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 dorsally, and several long white hairs ventrally up to the mouth opening. Proboscis mainly brown to black, except for yellowish brown distal division of labellum and yellowish brown base of proboscis. Labrum ca 6.1 mm, labellum approximately the same length. Thorax. Yellowish brown to light brown, with scutum not darker. Almost all setae black. Three long notopleural setae, 1 strong supra-alar seta, 2 strong postalar setae, 1 prescutellar dorsocentral seta, 1 apical scutellar seta, 1 small seta on anepimeron and 1 golden seta above fore coxa on propleuron. Black semi-adpressed hairs on scutum. Wing generally clothed in microtrichia, but bc, base of br, bm, base of dm and cup all virtually without microtrichia. Hind margin of wing with brown setulae. Venation as in Fig. 86 . Haltere orange-brown, distal part light brown. Legs whitish yellow, with brown hind femur. Legs with black and brown setae, except fore tibia entirely with white setulae and hind tibia with white setulae in the distal half on the posterior surface. All coxae with one large black seta laterally. Hind trochanter without an obvious 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 without erect black 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. Orange-brown, with tergites 3–6 with an inconspicious brown posterior margin, epandrium light 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 87–91 . Cercus elongated, not widened laterally. No teeth or obvious bristles at basal junction of cerci. Surstylus as shown in Figs 87–88 , lacking black teeth or fields of setulae. Base of surstylus with characteristic semicircular protuberance. Phallus sheath as illustrated in Fig. 90 ; anteriorly directed phallus sheath not protuding and not covered with spines. Anteroventrally there are a few small erect hairs.

Female unknown.

Etymology. The species is named after the Ivindo National Park, from which the holotype originates.

Discussion. Stylogaster ivindoensis belongs to a group of species which have a deeply curved radial cell r4+5 ( Fig. 86 ); a parallel sided ocellar triangle that reaches the base of the antennae ( Fig. 83 ); the basal flagellomere not obviously large, and with a dorsally situated arista ( Fig. 84 ); the scutum unicolourous with remaining thorax, without darker colouration ( Fig. 82 ); hind tibia white apically and with white setulae posteriorly; and legs without any obvious hairs or bristles. The following genital characters rule out almost all other species with the exception of Stylogaster westwoodi : cercus elongated ( Fig. 89 ); surstylus lacking any obvious black bristles, and with a characteristic semicircular protuberance ( Figs 87–88 ); phallus sheath of hypandrium without any bristles, anteroventrally with a few erect hairs ( Fig. 90 ). Stylogaster westwoodi and Stylogaster ivindoensis can be separated using the characters given in the key below. In Stuke (2012) Stylogaster ivindoensis keys out to couplet 7, from which further progress is uncertain due to its having only small brown markings on the tergites, and either option results in further problems because the colouration of the frons does not fit with any of the included species. Using Smith (1967) this species will be identified as Stylogaster westwoodi .

It is possible that Stylogaster ivindoensis is a synonym of one or other of the nomina dubia Stylogaster cohici Seguy, 1946 (described from „ Côte d’Ivoire: réserve du Banco) or Stylogaster bigoti Smith, 1967 (described from „S. Nigeria: Oshogbo). Both of these species were described from the female only and associated males cannot yet be assigned in the absence of specimens which have been unambiguously collected together.

Distribution. Stylogaster ivindoensis is only known from the locus typicus in Gabon.

Figures

FIGURES 82 – 86. Stylogaster ivindoensis spec. nov. (♂ holotype). 82. Lateral view of thorax and head. 83. Dorsal view of frons. 84. Lateral view of antenna. 85. Posterior view of hind tibia. 86. Wing.

FIGURES 87 – 91. Stylogaster ivindoensis spec. nov. (♂ holotype). 87. Lateral view of outer surface of surstylus. 88. Lateral view of inner surface of surstylus. 89. Dorsal view of cercus. 90. Lateral view of phallus sheath. 91. Tip of aedeagus.