Acantothereva oblata, Holston, Kevin C., 2009

Holston, Kevin C., 2009, A new species of Acantothereva Séguy, 1935, from Tunisia (Diptera: Therevidae: Therevinae): taxonomic consequences and phylogenetic implications, Zootaxa 2155, pp. 28-36 : 33-34

Acantothereva oblata sp. nov.

( Figs 1 , 2, 5A–D)

Diagnosis. The Tunisian species A. oblata , sp. nov., has a vertex with a non-dilated ocellar tubercle in comparison to the expanded, swollen tubercle and vertex of A. rungsi and moderately expanded tubercle of A. punctipennis Lyneborg (Fig. 2). The vertex of A. oblata , sp. nov., is lower than the dorsal eye margin, and the frontal setae are moderately dense. Acantothereva oblata , sp. nov., can also be distinguished from the other two Acantothereva species by dark femoral cuticle and black macrosetae on the femora, tibiae, and tarsi.

Description, holotype male [MEI_157716]. Body length: 7.5 mm. Head. Ocellar tubercle with yellow setae. Eyes separated medially by 2X width of ocellar tubercle (Fig. 2). Lower frons and face not swollen with respect to dorsal outline of head along eye margin. Frons with brownish grey tomentum, setae yellow, erect; darker tomentum at boundary of lower frons forming a pair of crescent-shaped greyish-brown areas with denser complement of semi-reclinate brownish black setae. Tomentum of face grey; setae mixed yellow and brownish black. Antennae: scape 0.25 mm, cuticle black, setae mixed yellow and brownish black, macrosetae black; flagellum cuticle yellowish brown, equal in length to scape. Maxillary palpus cuticle yellowish brown, increasingly brown towards apex; setae yellowish white.

Thorax. Chaetotaxy: 3 np, 1 sa, 1 pa, 0 dc, 1 sc. Macrosetae black. Mesonotum and scutellum with brownish grey tomentum; setae yellow, erect. Acrostical vitta indistinct, yellow anteriorly, absent on posterior half of scutum. Pleuron with grey tomentum; setae of anepisternum and katatergite whitish yellow. Wing. Length: 6.5 mm. Wing membrane opaque white with brown maculation at crossveins and vein intersections, with additional maculation scattered along longer longitudinal veins (e.g., R1, Cu). Wing veins yellow, brown at areas of maculated areas of the wing membrane. Halter knob yellowish white, stalk brownish yellow. Legs. Coxae with white setae; macrosetae black (1 c1, 1 c2, 0 c3). Cuticle of fore- and hindfemur black, midfemur yellow dorsally. Femora lancolate and filiform setae white, macrosetae black: forefemur and midfemur with 2 av; hindfemur with 7 av. Tibiae and first tarsal segment cuticle yellow with black apex (cuticle of remainder of tarsus black), setulae black except a few dorsally on the tibia.

Abdomen. Cuticle black; setae filiform, yellow. Tergites with brown lateral tomentum forming a longitudinal abdominal stripe, dorsal and ventrolateral tomentum grey; setae reclinate, yellow; tergite 8 strongly sclerotized medially. Sternite tomentum brown. Intersegmental membrane yellow. Male terminalia (internal structures described for paratype MEI_157713, Figs. 5A–D). Epandrium cuticle black; setae yellow. Gonocoxite cuticle black, without outer process, setae yellowish brown to brownish black; ventral lobe robust with narrow fringe of setae along posteriomedial edge. Gonostylus broad; inner medial setae forming dense fringe (Fig. 5A). Dorsal apodeme of aedeagus broad, concave medially, quadate anteriorly (Figs.5C–D). Ejaculatory apodeme apex with longitudinal ridge laterally (Figs. 5C–D). Ventral apodeme broad and convex dorsally, apical (recurved) region shorter than posterior (basal) region; apex rounded (Figs. 5C–D). Distiphallus robust, hook-like in lateral view; apex broad and blunt (Figs. 5C–D).

Male variation. Body length: 6.5–8 mm. Thorax. Chaetotaxy: 4–5 np. Wing. Length: 4.5–7 mm. Legs. Fore- and midfemur with 0–4 av, hindfemur with 5–9 av.

Specimens collected on the Nabuel peninsula in northeast Tunisia have the midfemur cuticle mostly or entirely black, a more extensive complement of black setulae on the hindtibia, and lighter vestiture color: the majority of head, thorax, and abdominal tomentum is grey and setae are whitish yellow to white.

Females. Similar to males except as follows. Body length: 7.5–12 mm. 6.5–7.5. Head. Frons slightly wider; tomentum at boundary of lower frons darker brownish-grey; setae yellow. Wing. Length: 6–7.5 mm. Abdomen. Tergite setae erect, yellow and increasing in density towards apex; setae on tergite 9 long and curved. Acanthophorite (tergite 10) with narrow A2 setae, apices rounded.

Etymology. oblata (L., feminine) flattened at the poles (of a spheroid), in reference to the shape of the head in anterior view.

Distribution. Acantothereva oblatus , sp. nov., has been collected in northern Tunisia at four localities at or near the coast (Tabarka, Korba, Nabuel, and Bizerte) and one inland locality (Aïn Draham).

Number of specimens examined: 43. Holotype. TUNISIA: Jendouba, Tabarka area, [36.95444, 8.76], Zool. Mus. Cop. Exp., 7–18 May 1988, HT 3 (MEI_157716; ZMUC). Paratypes. TUNISIA: Jendouba, Tabarka area, [36.95444, 8.76], Zool. Mus. Cop. Exp., 7–18 May 1988, 4 PT 3 (MEI_157713, ZMUC 00511295–97; ZMUC), 4 PT ƤƤ (MEI_157722-25; ZMUC). Additional specimens: TUNISIA: Jendouba, 25 km SE Aïn Draham, [36.61793, 8.890523], Zool. Mus. Cop. Exp., 10–16 May 1988, 1 3 (MEI_157715; NHRS); Tabarka, [36.95444, 8.76], Zool. Mus. Cop. Exp., 24 Mar 1986, 1 3 (NHRS-DIPT 000000009; NHRS), 9 3 (MEI_157714, MEI_157718–19, MEI_157721, ZMUC 00511303–06, ZMUC 00511316; ZMUC); Tabarka area, [36.95444, 8.76], Zool. Mus. Cop. Exp., 7–18 May 1988, 5 3 (MEI_157718, ZMUC 00511298–301; ZMUC), 1 Ƥ (NHRS-DIPT 000000008; NHRS), 1 Ƥ ( ZMUC 00511302; ZMUC). Bizerte, Bizerte, [37.28333, 9.87], Hauser, M., 23 Jun 2001, 2 3 collected as immatures (MEI_136430, MEI_136431; NHRS); Remel, [37.26667, 9.88] Hauser, M., 12–17 Jun 2000, 1 3 collected as immature (MEI_157717; NHRS). Nabeul, 10 km N Korba, [36.66872, 10.85], Zool. Mus. Cop. Exp., 29 Mar 1986, 2 3, (MEI_157711, NHRS-DIPT 000000010–11; NHRS), 9 3 ( ZMUC 00511307–15; ZMUC), 1 Ƥ, (MEI_157712; NHRS).

Figures

FIGURE 1. Male habitus of Acantothereva oblata, sp. nov., [MEI _ 157717] reared from larva. Body length = 7.5 mm. FIGURES 2 – 4. Male heads of Acantothereva species, anterolateral view. Fig. 2. Acantothereva oblata, sp. nov. [MEI _ 157716]. Fig. 3. Acantothereva rungsi Séguy [ZMUC 00511317]. Fig. 4. Acantothereva punctipennis Lyneborg [MEI _ 120188].