First record of the monotypic genus Acanopsilus Kieffer, 1908 (Hymenoptera: Diaprioidea: Diapriidae) from the Eastern Palaearctic region

Abstract Background The monotypic genus Acanopsilus (Hymenoptera: Diapriidae), is hitherto known only from Europe, where it is widely distributed. New information The genus is here recorded for the first time from South Korea and China, which constitutes the first formal record of the species from the entire Eastern Palaearctic region. A detailed redescription and photographs of Acanopsilus heterocerus (Haliday, 1857) are provided. Also, Acanopsilus brevinervis Kieffer, 1909 is proposed as junior synonym of Anommatium ashmeadi Mayr, 1856 (syn. nov.).


Introduction
Acanopsilus, a monotypic genus of tribe Pantolytini (Diapriidae: Belytinae) was established (Kieffer 1908) based on the type species, Acanopsilus clavatus Kieffer. The genus is widely distributed in Europe, but has not yet been recorded outside the continent. Generally Acanopsilus is easily distinguished from other Pantolytini genera by the following characteristics: eyes bare; very long and slender scape with simple apical margin; femora slender; petiole cylindrical; antenna of female composed of 14 segments.
As a result of the present study, the known range of A. heterocerus is extended from Europe (Western Palaearctic) to South Korea and China (Eastern Palaearctic). A redescription of the species, along with figures of taxonomically important morphological features are provided.

Materials and methods
The terminology used in the present study follows Nixon (1957) and Masner and García (2002). The images were taken with the aid of an Axiocam HRc camera mounted on a Discovery V20 stereomicroscope (Carl Zeiss, Oberkochen, Germany) and were produced with AxioVision40AC software (Carl Zeiss, Oberkochen, Germany). Final plates were prepared in Adobe Photoshop CS6 (Adobe Systems Incorporated, San Jose, United States of America).

Taxon treatment
Mesosoma. Mesosoma much longer than width (15: 9); cervix with two large pits and bare in dorsal view; pronotal shoulders angled; epomia absent; mesoscutum convex and covered with long setae; notauli complete; humeral sulcus distinct; scutellum smooth, covered with long sparse setae and convex; anterior scutellar pit large and deep, transverse (5: 4), longer than remaining scutellar disc; posterior scutellar pits absent; mesosoma in lateral view clearly longer than high (25: 16); lateral part of pronotum smooth, bare and shiny; upper part of mesopleuron smooth, bare and shiny with deep sulcus under tegula, without sternaulus; lower part of mesopleuron smooth and covered with sparse setae; median keel of dorsellum prominent, tubercle-shaped; propodeum transverse; posterior margin of propodeum slightly emarginated; posterior transverse propodeal keel distinctly raised; median propodeal keel raised into ridge.
Wing. Fore wing with costal, subcostal, marginal and stigmal veins tubular; basal, cubital and medial veins pigmented; stigmal vein short, nearly perpendicular to the marginal vein, as long as post-marginal vein and half of marginal vein.
Metasoma. Petiole cylindrical in dorsal view smooth, bare, shiny, with irregular longitudinal keels, with long setae laterally and dense cushion of long setae ventrally; base of T2 with several costae, not angled in lateral view; following tergites with micropunctures medially and few long setae laterally; all sternites with sparse short setae.

Distribution
South Korea (new record), China (new record), widely distributed in Europe.