Trachionus brevisulcatus Cui & van Achterberg

Cui, Qian, van Achterberg, Cornelis, Tan, Jiang-Li & Chen, Xue-Xin, 2015, The genus Trachionus Haliday, 1833 (Hymenoptera, Braconidae, Alysiinae) new for China, with description of four new species, ZooKeys 512, pp. 19-37 : 25-28

Taxon classification Animalia Hymenoptera Braconidae

Trachionus brevisulcatus Cui & van Achterberg sp. n. Figs 22, 23-32, 45

Type material.

Holotype, ♀ (NWUX), "NW. China: Shaanxi, Pingheliang, Ningshan, c. 2000 m, 27.vi.2011, 33°48'N, 108°50'E, Jiangli Tan, NWUX". Paratypes (ZJUH, RMNH): 4 ♀, topotypic and same date.

Diagnosis.

Scutellum largely smooth, at most punctulate and nearly flat; mandible black, medially with irregular transverse crest and with minute fourth and fifth teeth (Figs 28, 30, 45); temple smooth and medium-sized (Fig. 29); propleuron without transverse carina subposteriorly; sternaulus absent; median groove of mesoscutum and notauli wide posteriorly; metanotal spine medium-sized, its highest point remaining below level of tips of setae of scutellum (Fig. 32); propodeum angularly lowered posteriorly in lateral view and carina hardly protruding postero-laterally (Fig. 25); transverse carina of propodeum coarsely developed and irregular; medial third of hind tibia brownish yellow; basal half of second metasomal tergite coarsely rugose-striate, with about 30 striae and very shiny (Fig. 26); rugae of third tergite with distinct shiny interspaces. Similar to Trachionus hians , but this species has a strong transverse carina at the propleuron subposteriorly (without transverse carina in Trachionus brevisulcatus ) and basal half of second metasomal tergite largely finely aciculate (basal half of second tergite moderately striate).

Description.

Holotype, female; body length 3.5 mm, forewing length 3.5 mm.

Head. Width of head 2.1 × its median length, head dorsally smooth, strongly shiny and largely sparsely setose; antenna with 37 segments,1.2 × longer than fore wing, third segment 1.3 × as long as fourth segment, length of third, fourth and penultimate segments 2.9 ×, 2.3 × and 1.4 × their width, respectively; frons slightly depressed behind antennal sockets and smooth; eye in dorsal view 2.2 × as long as temple; temple in dorsal view directly roundly narrowed, smooth and near mandible punctulate; OOL: diameter of ocellus: POL= 10:3:3; face weakly convex, with long downward pointing setae laterally, punctulate and largely smooth; clypeus hemi-circular, smooth with some fine punctures and convex; eye glabrous; mandible nearly touching eye, length of malar space less than 0.1 × basal width of mandible; mandible 1.1 × as long as its maximum width and 1.2 × as long as its basal width, largely rugose medially and basally; mandible with irregular transverse crest, two wide lateral lobes and minute ventral fourth and fifth teeth; maxillary palp as long as height of head.

Mesosoma. Length of mesosoma 1.5 × its height; pronotum laterally punctate; propleuron without transverse carina subposteriorly; epicnemial area largely punctate; precoxal sulcus complete, wide and coarsely crenulate; sternaulus absent; remainder of mesopleuron smooth, but dorsally punctate; episternal scrobe large; pleural sulcus finely crenulate; mesosternal sulcus medium-sized and moderately crenulate, posteriorly widely reticulate; metapleuron narrowly smooth anteriorly and mainly coarsely punctate-reticulate; notauli deep and completely crenulate, united medio-posteriorly in wider reticulate area; median groove of mesoscutum complete and crenulate, mesoscutum smooth, shiny and only anterior half of middle lobe and area near notauli setose; scutellar sulcus very deep and with 3 longitudinal carinae, 0.4 × as long as scutellum; scutellum largely smooth, with few fine punctures and nearly flat; metanotal spine medium-sized, its highest point remaining below level of tips of setae of scutellum (Fig. 32); propodeum angularly lowered posteriorly in lateral view and carina hardly protruding postero-laterally (Fig. 25); transverse carina of propodeum coarsely developed and irregular; surface of propodeum mostly reticulate and medio-longitudinal carina present anteriorly.

Wings. Pterostigma elliptical; marginal cell of forewing elongate; vein r issued after middle of pterostigma (Fig. 23); r:2-SR:3-SR+SR1 = 6:10:42; SR1 curved; 1-CU1:2-CU1 = 2:19; CU1b present; m-cu antefurcal; 1-CU1 hardly widened; M+CU1 sclerotized. Hind wing: M+CU:1-M:1r-m = 33:14:20; cu-a straight; m-cu vaguely indicated.

Legs. Hind coxa largely smooth and with long setae; tarsal claws medium-sized (Fig. 31); length of femur, tibia and basitarsus of hind leg 3.7, 6.0 and 3.9 × their width, respectively; all femora widened.

Metasoma. Length of first tergite 1.1 × its apical width, its surface punctate-rugose, with dorsal carinae converging medially and united in distinct median carina (Fig. 26); second tergite strongly rugose; basal half of third metasomal tergite moderately striate and strongly shiny, remainder smooth; combined length of second and third metasomal tergites 0.7 × total length of metasoma (Figs 26-27); rugae of third metasomal tergite with distinct shiny interspaces; setose part of ovipositor sheath 0.1 × as long as fore wing; hypopygium large and apically acute (Fig. 27).

Colour. Black (including mandible); palpi, tegulae and legs yellow, but tarsi and base of coxa darkened; hypopygium partly brown; pterostigma and veins dark brown; wing membrane slightly infuscate.

Variation.

Forewing length 3.5-3.6 mm, body length 3.5-3.9 mm; antenna 35 (1 ♀), 36 (1 ♀) and 37 (1 ♀) segments; hypopygium largely brownish yellow or dark brown.

Distribution.

China (Shaanxi).

Etymology.

The name is derived from “brevis” (Latin for “short”) and “sulcus” (Latin for “groove”) because of the short widened parts of precoxal sulcus and notauli.