Yezoceryx pacoensis, Achterberg, 2017

Achterberg, Cornelis Van, 2017, First record of the genus Yezoceryx Uchida (Ichneumonidae: Acaenitinae) from Vietnam, with descriptions of nine new species, Zootaxa 4311 (3), pp. 345-372 : 357-359

Yezoceryx pacoensis sp. nov.

( Figure 9 )

Diagnosis. Body black with head extensively yellow on inner and outer orbits; occipital carina deeply concave dorsally; antenna with median whitish flagellomeres; first tergite 2.4× as long as posterior width; first sternite with sharp anterior-facing hook; ovipositor about 3.3× length of hind tibia.

Material examined. Holotype: ♀ ( IEBR), Hoa Binh, Mai Chau, Pa Co , 23.iv.2002, 1100 m a.s.l., T.V. Hoang leg.

Description of female holotype. Head. Antenna with 36 flagellomeres, first flagellomere 1.1× length of second; frons concave and polished medially, swollen and punctate laterally; face 0.65× as high as wide, with large punctures laterally, medially swollen and puncto-striate; clypeus about 0.45× as high as wide, with shallow punctures, with median and lateral tubercles; malar space equal to basal width of mandible; mandible with irregular striations, lower tooth of mandible equal to upper tooth, inner margins of eyes divergent ventrally; diameter of lateral ocellus 0.5× ocellar-ocular distance; vertex matt, with moderately dense punctures; occipital carina deeply concave dorsally, ventrally meeting hypostomal carina 1.0× basal mandible width from base of mandible.

Mesosoma. Epomia 0.9× mandible basal width; pronotum with transverse striations across median groove, upper posterior corner with large, dense punctures; mesoscutum 0.9× as long as wide at anterior level of tegulae, matt, with dense, coarse punctures; convergence area of notauli with irregular sinuous wrinkles; scuto-scutellar groove with two strong plus some weak carinae; scutellum smoother than mesoscutum with shallow punctures, pubescent, lateral carina extending nearly to apex; postscutellum polished, impunctate; mesopleuron with dense, small punctures dorsally and anteriorly, pubescent, ventral half with dense striae mixed with large punctures, epicnemial carina complete, posterior transverse carina of mesosternum present medially; metapleuron with dense, largely punctures, pubescent; propodeum with irregular wrinkles, area basalis round posteriorly, area externa and area dentipara defined, area petiolaris polished, impunctate, pleural parts of anterior and posterior transverse carinae present; fore basitarsus 2.5× second tarsomere; mid basitarsus 2.4× second tarsomere; hind leg with femur 3.0× as long as wide, 0.8× length of tibia, tarsus 0.9× tibia length, basitarsus 1.9× second tarsomere, fifth tarsomere 2.1× longer than third. Fore wing length 11 mm, vein Rs&M opposite cu-a, vein 2 rs-m basad of 2 m-cu by about 0.3× length of 2 rs-m, first abscissa of hind wing vein Cu 1 equal to cu-a.

Metasoma. Tergites with moderately dense, small punctures, pubescent; first tergite 2.4× as long as posterior width, lateral longitudinal carina present anteriorly, not reaching to spiracle; second tergite 0.5× as long as first tergite, and equal to third; first sternite with sharp, anteriorly projecting hook; ovipositor about 3.3× as long as hind tibia; hypopygium 1.8× as long as second tergite.

Colour. Black. Antenna black, except flagellomeres 10-21 whitish or partly whitish, face yellow with median black longitudinal stripe; frons yellow laterally; clypeus black with lateral yellowish mark; ventral two thirds of outer orbit and malar space yellow, tegula and fore and mid legs yellow, except coxae; hind leg with yellow trochanter and trochantellus, femur brown except extreme proximally and distal fifth yellow, tibia and tarsus yellow; metasomal tergites with narrow yellowish brown posterior margins, ovipositor yellow, ovipositor sheath brown, hypopygium black with dorsal margin and posterior narrowed section yellow; fore wing with distal band and area below pterostigma slightly infuscated.

Male. Unknown.

Comparison. According to Cameron (1899) and Chiu (1971), the new species is most similar to Y. nigricans (Cameron) in the shape of the occipital carina and in general colour. It can be separated from Y. nigricans by the median white band on the antennal flagellum and the largely yellow face and legs, whereas Y. nigricans (holotype female in BMNH examined) is almost entirely black, except for white inner orbits of the face.

Etymology. Named after the type locality.

Distribution. Currently known only from Mai Chau, Hoa Binh Province, North Vietnam ( Figure 19 ).

Figures

FIGURE 9. Yezoceryx pacoensis sp. nov.: a. lateral view; b. face; c. lateral view of mesosoma; d. dorsal view of head; e. lateral view of first metasomal tergite; f. dorsal view of propodeum.

FIGURE 19. Map of sampling sites of Yezoceryx spp in Vietnam: 1. Cao Bang Province; 2. Bac Kan Province; 3. Vinh Phuc Province, 4. Son La Province; 5. Hoa Binh Province; 6. Ninh Binh Province; 7. Nghe An Province; 8. Thua Thien-Hue Province; 9. Kon Tum Province; 10. Dak Lak Province; 11. Dong Nai Province.