Zethus propodeus Nguyen & Carpenter

Lien Thi Phuong Nguyen & James M. Carpenter, 2016, Taxonomic review of the genus Zethus Fabricius (Hymenoptera: Vespidae: Eumeninae) from Vietnam with descriptions of four new species, Entomological Science 2016, pp. 1-9 : 7-8

Zethus propodeus Nguyen & Carpenter , sp. nov

( Figs 29–32 )

Holotype, ♀, “ VIETNAM, Pi Oac NR , Thanh Cong , Nguyen Binh , Cao Bang , 22°32.5 ’ N 105°53 ’, 1000 m, 8. viii.2012, LTP Nguyen & IEC-c ” [ IEBR].

Description

Female. Holotype. Body length 17 mm; forewing length 14.5 mm. Structure as in Z. dolosus and Z. angulatus sp. nov. but differs as follows: body covered with coarser and more uniform punctures. Head in frontal view wider than high, 1.2× as wide as high ( Fig. 29 ). Inner eye margins in frontal view further apart from each other at vertex than at clypeus. Clypeus in frontal view 1.2× as wide as long, emarginated at basal margin and concave medially, apical margin nearly truncated ( Fig. 29 ). Mandible with four teeth, the third and fourth teeth truncated. FI 2× as long as its maximum width, FII – III as long as wide, FIV – IX wider than long, FX bullet-shaped, as long as its basal width. Propodeum ( Fig. 30 ) rugose, dull, without lateral carina, with 4 – 5 oblique striae along each side of medial carina, lateral side with small and sparse punctures, without striae, submarginal carina produced into round and short lamella above propodeal valvulae. Metasomal segment I proportionally shorter than in Z. dolosus , 2.6× as long as wide, in dorsal view gradually widening from one-fourth of the distance from base to basal half, then gradually narrowly toward apical margin ( Fig. 31 ), with maximum width 2.6× its basal width, with a medial carina which runs from basal margin to onefourth the length of the tergum, swollen part 2.1× as long as wide in dorsal view, tergum and sternum fused, area between two sides with undefined border, with small and clearly defined punctures, in lateral view dorsal and ventral margin not parallel. Metasomal segment II with rather long petiole at base (Figs 31,32), TII in lateral view slightly concave near base, then gradually convex to near apical margin, slightly depressed before apical margin, SII in lateral view gradually convex from base to apical margin ( Fig. 32 ).

Color. Black. Propodeal valvulae dark brown.

Distribution. Vietnam: Cao Bang.

Remarks. This species can be distinguished from the similar species Zethus malayanus Gusenleitner, 2010 and other known species of the genus by the combination of the following characters: body covered with rather uniform punctures and long hairs, metasomal segment I in lateral view with dorsal and ventral margin not parallel, propodeum rugose, without lateral carinae, submarginal carina produced into short and round lamella above propodeal valvulae, metasomal segment II with rather long petiole at base.

Etymology. The specific name refers to the propodeum with its diagnostic characters.

Figures

Figures 29 – 32 Zethus propodeus sp. nov., holotype ♀. 29 Head, frontal view. 30 Propodeum, dorsal view. 31 TI & II, dorsal view. 32 Metasomal segments I & II, lateral view. Scale bar, 1 mm.