Testudobracon descensus Long, 2023

Mai, Pham Quynh, Long, Khuat Dang, Hiep, Nguyen Duc, Hoa, Dang Thi & Duong, Tran Dinh, 2023, First record of the genus Testudobracon Quicke, 1986 (Hymenoptera: Braconidae: Braconinae) in Vietnam, with description of four new species, Zootaxa 5244 (5), pp. 485-500 : 490-492

Testudobracon descensus Long , sp. nov.

Figures 3–4

Material examined. Holotype, ♀, “Bracn. 1561 ” ( IEBR), NW Vietnam: Son La, Chieng Sinh, Quyet Tam , orchard, MT, 21°18’06’’N 103°55’36’’E, 663 m, 10.v.2017, KD Long.

Description. Holotype, female, length 3.2 mm; antenna 2.6 mm; fore wing 2.9 mm; ovipositor sheath 1.4 mm ( Fig. 3 ).

Head. Antenna with 23 flagellomeres; length of first flagellomere subequal to second flagellomere; first, second and penultimate flagellomeres 2.0, 2.0 and 1.2 × as long as wide; head 1.3 and 1.8 × as wide as long medially in frontal and dorsal view, respectively; frons and vertex anteriorly rugo-granulate ( Figs 4a, 4b ); occiput largely rogose; temple laterally coriaceous; malar space rugose; OOL: OD: POL= 7: 3: 3 ( Fig. 4a );; oculo-antennal groove indistinct; length of eye 3.25 × as long as temple in dorsal view; lateral temples smooth and shiny; height of eye: width of face: width of head = 16: 16: 33; face rugose ( Fig. 4b ); height of clypeus: inter-tentorial distance: tentorio-ocular distance = 2.5: 7.0: 5.0; clypeus with distinct postero-dorsal carina ( Fig. 4b ); length of malar space 1.75 × basal width of mandible.

Mesosoma. Length of mesosoma 1.2 × its height; mesoscutum with sparse and short setosetae; middle lobe more or less with medial longitudinal ridge ( Fig. 4d ); notauli complete, punctate, anteriorly with depressed area, narrowed medially and widened posteriorly, meeting scutelar sulcus; scutellar sulcus deep, with 7 carinae ( Fig. 4d ); scutellum convex, smooth; mesopleuron with a short and deep narrow pit medially ( Fig. 4f ); precoxal sulcus indistinct; mesopleuron coriaceous ventally and medially, transversely rugose dorsally; metapleuron rugo-punctate; propodeum with a complete mid longitudinal carina, smooth, setose latero-posteriorly.

Wings. Length of pterostigma 2.7 × its maximum width; fore wing vein 1-SR 0.4 × as long as 1-M; ratio of length of fore wing veins r: 3-SR: SR1= 5: 11: 36, and 2-SR: 3-SR: r-m = 10: 11: 6; second submarginal cell slightly narrowed distally ( Fig. 4k ). Hind wing vein C+SC+R with single straight hamulus and vein R1 with 3 curved hamuli apically; ratio of length of hind wing veins 1r-m: SC+R1 = 6: 10.

Legs. Length of fore femur: tibia: tarsus = 19: 21: 24; hind coxa smooth, setose; length of hind femur: tibia: basitarsus = 28: 33: 11.

Metasoma. First metasomal tergite rugose, 0.7 × as long as wide apically apically, deeply impressed mediobasally and carinate medially; second metasomal tergite basally 1.8 × wider than long, with sublateral grooves, rugose, setose ( Fig. 4d ); second metasomal tergite 1.1 × as long as third tergite medially; second metasomal tergite areolate-rugulose medially ( Fig. 4c ); third tergite confused rugulose; fourth-sixth metasomal tergites finely irregularly rugose medially, rugose laterally ( Fig. 4g ); sixth metasomal tergite with rounded postero-lateral lobes; medial emargination (incision) deep ( Fig. 4h ), 0.6 × as long as tergite medially, and 0.7 × as long as wide; ovipositor abruptly bent downward ( Fig. 4i ), 1.0 × metasoma in lateral view, and 0.6 × as long as fore wing ( Fig. 3 ).

Colour. Antenna brown; stemmaticum dark brown; head, pronotum yellow; mesoscutum and mesopleuron ventrally reddish yellow; scutellum, mesopleuron dorsally, mesosternum and propodeum brown to dark brown ( Fig. 4f ); fore and middle legs yellow; hind coxa, femur and tibia dark brown, except hind tibia basally, hind trochanters + trochantellus and hind tarsus pale yellow; wing veins yellowish brown; metasomal tergites 1–3 yellow, except 1st tergite apically, 2nd–3rd tergites medially dark brown; 4th–6th tergites pale yellow; postero-lateral lobes of 3rd–5th tergites and 3rd-4th metasomal sutures yellowish brown ( Fig. 4h ); ovipositor sheath brown; ovipositor yellow.

Male. Unknown.

Distribution. NW Vietnam (Hoa Binh, Son La).

Biology. Unknown.

Etymology. From Latin “descensus” meaning “downward course”, because ovipositor abruptly bent downward subapically.

Notes. Testudobracon descensus sp. nov. is close to T. niger Quicke , from Indonesia, but differs from the latter by the following characters: 1) Vein 3-SR of fore wing 1.65 × vein r (1.8 × in T. niger ); 2) Second sub-marginal cell of fore wing almost not narrowed apically; and 3) Propodeum and medio-dorsal area of 3rd tergite blackish brown to black; third-fourth metasomal suture brown.

Figures

FIGURE 3. Habitus of Testudobracon descensus Long, sp. nov., holotype, female (lateral)

FIGURES 4a–k. Testudobracon descensus Long, sp. nov., holotype, female, a Head, dorsal b Head, frontal c First-third metasomal tergites, dorsal d Mesonotum e Head, lateral f Mesopleuron g Metasoma, lateral h Fourth-sixth metasomal tergites, dorsal i Apex of ovipositor, lateral k Fore wing