Leiobracon Long & van Achterberg, 2024

Dzuong, Nguyen Van, Long, Khuat Dang, Achterberg, Cornelis Van & Hiep, Nguyen Duc, 2024, Leiobracon, a new genus of the subfamily Braconinae (Hymenoptera, Braconidae) from Vietnam, Zootaxa 5453 (3), pp. 387-394 : 388

Leiobracon Long & van Achterberg , gen. nov.

( Figures 1 , 2 )

Type species: Leiobracon vietnamicus Long & van Achterberg , sp. nov.

Diagnosis. Body medium-sized and about 8 mm in length, reddish yellow; scape nearly globose, longer dorsally than ventrally in lateral view; terminal flagellomere apiculate/mucronate; in lateral view face with dense and long setosity; clypeus separated from coriaceous face by a fine carina; glossa long, deeply bilobed; galea rather long, broad ( Fig. 2B ); maxillary palp 5-segmented; labial palp 3-segmented; notauli absent; scutellar sulcus narrow, shallow and smooth; in lateral view pronotum densely setose; mesopleuron convex, smooth; propodeum smooth; hind tibial spurs straight, setose; tarsal claws with small inner tooth and widened subbasally; vein 1-SR+M of fore wing strongly curved posteriorly after arising from vein 1-SR and vein r of fore wing long ( Fig. 2H ); apex of vein C+SC+R of hind wing with one short, robust bristle; apex of vein R1 with three curved hamuli; vein 2-SC+R vertical and vein 1r-m long ( Fig. 2I ); vein cu-a strongly reclivous; first metasomal tergite elongate, 2.9 × longer than width apically ( Figs 1B , 2F ); metasoma entirely smooth; hypopygium sclerotized throughout, acute apically and reaching apex of metasoma ( Fig. 1C ); ovipositor sheath densely setose, subequal to hind tibia; ovipositor with pre-apical dorsal nodus and apico-ventral serrations ( Fig. 2G ).

Distribution. Oriental ( Vietnam; one species).

Biology. Unknown.

Etymology. Name derived from “leios” (Greek for smooth, bald), because of the smooth body, and the generic name Bracon Fabricius.

Comments. Leiobracon gen. nov. shares with other genera of the Mesobracon group of genera the bifurcate tarsal claws ( Quicke 1987) and the comparatively long vein r of the fore wing, but can be distinguished by having the metasoma largely smooth (vs metasoma coarsely sculptured in Mesobracon group of genera) and vein 1-SR+M of fore wing strongly bent (vs straight). Tarsal claws bifurcate or with a small separate tooth on its inner side found in the new genus and other Mesobracon group of genera may be interpreted as the plesiomorphic state. The new genus resembles the Myosoma group of genera by sharing the following synapomorphies: the first metasomal tergite more than 2.6 × longer than wide medially and its lateral areas largely reduced, the second metasomal tergite triangular, the outer side of the hind femur and tibia densely setose and with longitudinal depression, the metasoma smooth and shiny and the second metasomal suture smooth.

Figures

FIGURE 1. Leiobracon vietnamicus Long & van Achterberg, sp. nov., holotype, female. A Habitus, lateral B Metasoma, dorsal C Ovipositor and apex of metasoma lateral.

FIGURE 2. Leiobracon vietnamicus Long & van Achterberg, sp. nov., holotype, female. A Head, dorsal B Head, anterior C Head, lateral D Mesonotum, dorsal E Hind telotarsus and tarsal claw F Metasomal tergites 1–3, dorsal G Apex of ovipositor, lateral H Fore wing I Hind wing.