Trachyusa whartoni Yao

Yao, Junli, Kula, Robert R. & Chen, Jiahua, 2015, A new species in the newly recorded genus Trachyusa (Hymenoptera: Braconidae: Alysiinae) from China, Zootaxa 3931 (4), pp. 579-584 : 581-583

Trachyusa whartoni Yao , sp. nov.

( Figs 1–10 )

Diagnosis. Face 1.15–1.50X longer than wide ( Fig. 3 ); mesoscutum long, 1.10–1.30X longer than wide ( Figs 4 , 7 ); notauli wide and long, extending posteriorly beyond middle of mesoscutum, almost reaching mesoscutal midpit, mesoscutal midpit narrow and long ( Fig. 7 ); sternaulus long and curved, incomplete, present medially ( Figs 6 , 10 ); metanotum with ridge terminating into arch-shaped carina ( Fig. 7 ); metacoxa smooth with long setae, almost as long as trochanter ( Fig. 10 ); second metasomal terga and basal of third and fourth metasomal terga granulate ( Fig. 8 ); mesosoma and metasoma dark yellow.

Body length. 2.70 mm (based on holotype only).

Head. Antenna with 26–28 flagellomeres, almost uniformly thick, only weakly narrowing basally to apically ( Fig. 2 ); first flagellomere 1.10–1.20X longer than second flagellomere, first flagellomere 4.50–5.75X longer than its width apically, penultimate flagellomere 1.70–2.00X longer than apical width; head width 1.67–2.25X wider than medial length, 1.50X wider than maximum length, head behind eyes rounded, evenly slightly narrowed, almost parallel-sided, converging ventrally ( Fig. 4 ); transverse diameter of eye 1.50X longer than temple; face 1.15–1.50X wider than high, with weak medial ridge and dense, long setae ( Fig. 3 ); base of mandible ( Fig. 5 ) with sparse, long, white setae, 1st and 3rd tooth very small, 2nd tooth wide and sharp and with orthogonal protuberance on upper margin.

Mesosoma. Mesosoma 1.60X longer than high; propleuron smooth with several weak ridges ( Fig. 5 ); mesoscutum slender and 1.10–1.30X longer than wide ( Figs 4 , 7 ); notauli wide and long, extending posteriorly beyond middle of mesoscutum, almost reaching mesoscutal midpit, midpit narrow and long, not extending to transscutal articulation ( Figs 4 , 7 ); scutellar sulcus with distinct medial ridge and several weak lateral ridges ( Fig. 4 ); mesopleuron smooth, sternaulus long and curved, medially distinct ( Fig. 6 ); metanotum with ridge terminating into arch-shaped carina; propodeum areolate-rugose, spiracle distinct ( Fig. 7 ).

Wings. Fore wing 2.90X longer than maximum width ( Fig. 1 ); pterostigma elliptical, 3.50X longer than wide, r very short, 1/5 length of pterostigma width, arising slightly distad middle of pterostigma; 3RSa 0.80–0.90X longer than 2RS; 2nd submarginal cell 1.80–2.30X longer than width ( Fig. 1 ); (RS+M)a, 2M, and 2RS slightly curved; 1cu-a slightly postfurcal ( Fig. 1 ).

Legs. Metacoxa smooth, with very long setae, tarsus setose ( Fig. 10 ).

Metasoma. First tergum 1.60–1.65X longer than apical width, 2.65–2.80X longer than basal width ( Fig. 8 ); second tergum 1.45X longer than basal width, maximum width 1.20X longer than length of second tergum ( Fig. 8 ); metasomal terga 1–2 and visible portion of 3rd and 4th except posterior margin punctate-rugose ( Fig. 8 ); ovipositor short, less than length of first tergum, slightly protruding beyond apex of metasoma, ovipositor sheath setose ( Fig. 9 ).

Colour. Head dark reddish brown; antenna brown, scape, pedicel, first and second flagellomere light brown; mesosoma and metasoma entirely yellow; pterostigma mostly light brown and apical 1/3 weakly infuscate; legs entirely yellow; mesosoma and metasoma dark yellow.

Male. Unknown.

Variation. The two specimens, both females, are almost the same morphologically except the flagellum varies from 26–28 flagellomeres.

Type material. Holotype: ♀ China: Liaoning, Dalian Taishan, 5–VII–2012, Chunguang CHANG. Paratype: 1 ♀ same data as holotype except 8–VII–2012. Both types deposited in Beneficial Insects Institute, Fujian Agriculture & Forestry University, Fuzhou, China.

Remarks. This species is very similar morphologically to T. vasilisk , but in T. vasilisk the notauli are narrow and distinct on the anterior part of the mesoscutum only, 3RSa is as long as 2RS, the metacoxae are more or less sculptured, and the mesosoma and metasoma are brown or dark brown. In T. whartoni the notauli are wide, long, and sculptured; 3RSa is shorter than 2RS; the metacoxae are smooth; and the mesosoma and metasoma are dark yellow. This species is also close morphologically to T. aurora , but in T. aurora the notauli are narrow and complete (i.e., reach the midpit), the scutellum is flat, the metacoxae are densely granulate-rugulose, and 3/5 of the third tergum is shagreened and finely punctate. In T. whartoni the notauli are as described above, the scutellum protrudes, the metacoxae are smooth with white and long setae, and metasomal terga 1–3, as well as 1/2 of tergum 4, are densely shagreened and finely punctate.

Biology. Unknown.

Etymology. This species is named in honor of Professor Robert A. Wharton for the guidance on alysiine systematics he provided to the first author.

Figures

FIGURES 1 – 6. Trachyusa whartoni Ya o, sp. nov. 1. Lateral habitus. 2. Head and antennae, lateral view. 3. Head, anterior view. 4. Head and mesoscutum, dorsal view. 5. Head, lateral view. 6. Head and mesosoma, lateral view.

FIGURES 7 – 10. Trachyusa whartoni Yao, sp. nov. 7. Mesosoma, dorsal view. 8. Metasoma, dorsal view. 9. Metasoma, lateral view. 10. Meso- and metathoracic legs, lateral view.