Spathius aciculatus, Tang & Belokobylskij & Chen, 2015

Tang, Pu, Belokobylskij, Sergey & Chen, Xue-Xin, 2015, Spathius Nees, 1818 (Hymenoptera: Braconidae, Doryctinae) from China with a key to species, Zootaxa 3960 (1), pp. 1-132 : 15-17

Spathius aciculatus sp. nov.

( Fig. 1 )

Description. Female. Body length 4.5 mm; fore wing length 3.3 mm.

Head. Antennae almost filiform, more than 25-segmented (apical segments missing). Scape 1.4 × as long as its maximum width. First flagellar segment 5.5 × as long as its apical width, as long as second segment. Head width (dorsal view) 1.7 × median length. Head behind eyes (dorsal view) roundly narrowed; transverse diameter of eye 1.9 × length of temple. Ocelli medium-sized, arranged in triangle with base 1.3 × its sides; POL: Od: OOL = 6: 5: 12. Vertex and frons entirely densely aciculate. Eye glabrous, 1.4 × as high as broad. Malar space 0.4 × eye height and equal to basal width of mandible. Temple almost smooth, with very fine striation. Face with very dense, fine and absolutely even transverse aciculation (like surface of gramophone record or CD); its width 1.1 × eye height and 1.1 × height of face and clypeus combined. Clypeal suture absent. Hypoclypeal depression rather small and round, its width 0.6 × distance from edge of depression to eye, 0.3 × width of face. Occipital carina complete dorsally, not joined with hypostomal carina being obliterated upper base of mandible.

Mesosoma. Length of mesosoma 2.0 × its height. Pronotal keel fine, its posterior branch widely fused with posterior margin of pronotum, anterior branch situated submedially on pronotum. Mesoscutum highly and roundly elevated above pronotum, its median lobe convex anteriorly and without anterolateral corners. Mesoscutum mostly glabrous, with rather sparse, more or less long and almost erect pale setae arranged narrow along notauli and laterally, densely and small reticulate-areolate with additional very fine granulation, lateral lobes of mesoscutum only granulate; with two distinct and convergent posteriorly carinae medioposteriorly. Notauli anteriorly distinct, wide, crenulate, very shallow in posterior half. Prescutellar depression deep, long, with four carinae, finely rugulose-reticulate, 0.4 × as long as scutellum. Scutellum entirely densely granulate, distinctly convex, with distinct lateral carinae. Mesopleuron weakly rugulose. Subalar depression very shallow, wide, finely reticulate-granulate and with sparse striae. Precoxal sulcus distinct, deep, weakly curved, crenulate, running along anterior half of lower part of mesopleuron. Propodeum with very short and wide lateral tubercles, with distinctly delineated by carinae and granulate basolateral areas, its rest part coarsely and transversely striate with rugosity; areola narrow and short; basal carina present in basal half, 3.0 × as long as anterior fork of areola.

Wings. Fore wing 3.7 × as long as wide. Vein r arising behind middle of pterostigma. 3-SR: r: SR1: 2-SR = 20: 5: 27: 16. Second submarginal cell not narrowed distally, its length 3.5 × maximum width, 1.45 × length of first subdiscal cell. Vein CU1a interstitial. Hind wing vein M+CU 0.5 × as long as vein 1-M. Vein m-cu distinctly antefurcal, weakly curved and strongly oblique towards base of wing.

Legs. Hind coxa dorsally finely transversely striate, widely and densely granulate at rest part, with basoventral tooth and corner. Hind femur distinctly and densely granulate-coriaceous, smooth ventrally, 3.1 × as long as wide. Hind tibia apically without spines on outer side. Dorsal surface of hind tibia with long, sparse and semi-erect setae, their length 0.9–1.0 × maximum width of tibia. Hind tarsus 0.9 × as long as hind tibia. Hind basitarsus 0.7 × as long as second-fifth segments combined. Second segment of hind tarsus 0.5 × as long as basitarsus, as longer as fifth segment (without pretarsus).

Metasoma. Petiole (lateral view) weakly curved ventrally, dorsally arched in basal third and straight in apical two-thirds, thickened in basal third; widened in apical quarter (dorsal view), with spiracular tubercles in basal third; distinctly reticulate-rugulose and with sparse striae in basal 0.7, finely striate apically. Length of petiole 3.0 × its apical width (dorsal view), 1.9 × length of propodeum. Second tergite with separate laterotergites only basally. Median length of second and third tergites combined 1.25 × basal width of second tergite, 0.7 × as long as their maximum width. Second suture absent. Second and third tergites densely reticulate-granulate, almost smooth narrowly apically. Fourth tergite densely reticulate-granulate, almost smooth narrowly apically. Remaining tergites smooth. Ovipositor straight. Ovipositor sheath 2.3 × as long as petiole, as long as metasoma, 1.5 × as long as mesosoma, 0.8 × as long as fore wing.

Colour. Body yellowish brown, precoxal sulcus reddish brown. Antennae yellow brown. Palpi pale yellow. Legs pale yellowish brown, fore and middle coxae and all trochanters white, hind coxa white with infuscation; all tibiae white basally; hind leg brownish yellow. Ovipositor sheath brownish yellow in basal half and black in apical half. Fore wing faintly infuscate, with brown spots near vein 1-SR, 1-M and pterostigma. Pterostigma brown, pale in basal third.

Male. Unknown.

Material examined. Holotype: female, China, Hainan Prov., Jianfengling , 7.VI.2007, Liu Jingxian, No. 200702556 ( ZJUH).

Comparative diagnosis. This new species belongs to the S. vulnificus Wilkinson species group. Spathius aciculatus sp. nov. is similar to S. paracritolaus Belokobylskij , but differs in having the petiole longer, its length 3.0 × apical width and 1.9 × length of propodeum (2.0 × its apical width and 1.5 × length of propodeum in S. paracritolaus ); vein CU1a interstitial (not interstitial in S. paracritolaus ); mesoscutum densely and small reticulate-areolate with additional very fine granulation (finely and densely reticulate in S. paracritolaus ); vertex entirely densely aciculate (laterally smooth, finely aciculate only medially in S. paracritolaus ); ovipositor long (short in S. paracritolaus ).

Etymology. From “aciculus” (Greek for “aciculate”), because its aciculate sculpture on vertex and frons.

Distribution. China (Hainan).

Figures

FIGURE 1. Spathius aciculatus sp. nov. A, habitus, lateral aspect; B, head, frontal aspect; C, head, dorsal aspect; D, fore wing; E, petiole, lateral aspect; F, mesoscutum, dorsal aspect; G, mesosoma, lateral aspect; H, metasoma, dorsal aspect. Scale bar 0.5 mm.