Yezoceryx coronatus, 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 : 352-354

Yezoceryx coronatus sp. nov.

( Figure 4 )

Diagnosis. Yellow with black marks; mesoscutum with black mark rather crown-shaped; face densely granulate, granulations radiating from centre; first tergite 1.6× as long as posterior width; first sternite projection blunt, hooked anteriorly; ovipositor 1.8× as long as hind tibia.

Material examined. Holotype: ♀ ( RMNH), Dong Nai, Cat Tien NP, Crocodile trail, 9–26.iv. 2007, 100 m a.s.l., Malaise trap, P. Q. Mai & T. M. Nguyen leg. ; Paratypes: 1♀ ( IEBR), similar data as holotype, 1♀ ( RMNH), Ninh Binh, Cuc Phuong NP, near centre, 10.ii–15.iii. 2000, 225 m a.s.l, P. Q. Mai leg. ; 1♀ ( RMNH), Ninh Binh, Cuc Phuong NP, near centre, 15–27.v. 2000, 225 m a.s.l, P. Q. Mai leg

Description of holotype female. Head. Antenna with 25 flagellomeres, first flagellomere 1.2× length of second; frons concave and polished medially, punctate laterally, carina between antennal sockets extending to elevated part of face; face with dense, radiating granulation, 0.65× as high as wide, medially swollen; clypeus about 0.5× as high as wide, sculptured as face, subapical margin with median and lateral tubercles; malar space equal to basal width of mandible; mandible with transverse striation proximally, lower tooth of mandible much longer than upper, inner margins of eyes divergent ventrally; diameter of lateral ocellus 0.8× ocellar-ocular distance; vertex with sparse, fine punctures; occipital carina evenly curved, ventrally meeting hypostomal carina about 0.6× basal mandible width from base of mandible.

Mesosoma. Epomia equal to mandible basal width; pronotum with strong striations across median groove, posterior corner densely punctate; mesoscutum 0.85× as long as wide at anterior level of tegulae, with dense, moderate-sized punctures, pubescent, convergence area of notauli with two long median carinae and strong irregular wrinkles laterally; scuto-scutellar groove with one median and two oblique lateral carinae; scutellum convex, densely punctate, pubescent, lateral carina present anteriorly; postscutellum polished, impunctate; mesopleuron with moderate-sized punctures, pubescent, except concave, smooth area medially, epicnemial carina complete, sharp, posterior transverse carina of mesosternum present medially; metapleuron densely punctate, pubescent; propodeum with dense, small punctures anteriorly, area basalis wider than long, anterior transverse carina weakly angulate medially, area dentipara nearly defined, pleural area polished, impunctate, pleural parts of anterior and posterior transverse carinae present; fore basitarsus 2.3× second tarsomere; mid basitarsus 2.7× second tarsomere; hind leg with femur 2.7× as long as wide, 0.7× length of tibia, tarsus 0.7× tibia length, basitarsus 2.6× second tarsomere, fifth tarsomere 2.4× longer than third. Fore wing length 7.8 mm, vein Rs&M slightly distad of cu-a, vein 2 rs-m about 5× distance between 2 rs-m and 2 m-cu, hind wing with first abscissa of vein Cu 1 equal to vein cu-a.

Metasoma. Tergites with small punctures, pubescent; first tergite 1.6× as long as posterior width, punctate medially and apico-laterally, lateral longitudinal carina present not extending to level of spiracle; second tergite 0.4× as long as first tergite, equal to third; first sternite with projection hooked anteriorly; ovipositor 1.8× as long as hind tibia; hypopygium 2.2× as long as second tergite.

Colour. Yellow. Antenna black, except scape, pedicel and first two flagellomeres yellow ventrally; frons with paired black spots at concave, impunctate area, vertex with a black band extending from eyes to ocelli, occipital area black; mesoscutum with black mark at anterior edge of median lobe and trilobed black mark posteriorly, shaped rather like a crown, tegula black, apex of scutellum and postscutellum black, mesopleuron with black mark along anterior margin, metapleuron with black spot at anterior margin, propodeum black anteriorly, metasomal tergite 1 black medially and baso-laterally, tergites from second onwards each with black stripe anteriorly, ovipositor sheath light brown, blackish apically, fore wings with distal part and area below prestigma infuscate, mid leg with brown on coxa and femur, hind leg with black marks on coxa, trochanter, trochantellus and femur, tibia reddish with black marks proximally and distally, tarsus black.

Male. Unknown.

Variation: Paratypes have antennae with 22-23 flagellomeres. Fore wing vein 2 rs-m varies from 1.0 to 3.3× distance between 2 rs-m and 2 m-cu. Hind wing first abscissa of vein Cu 1 is slightly longer than vein cu-a. The paratype collected in Cat Tien NP (similar data to the holotype) has fore wing vein Rs&M opposite cu-a. One paratype collected in Cuc Phuong NP with first tergite 1.4× as long as its posterior width.

Comparison. In general colour pattern, the new species is similar to Yezoceryx biumbratus (Morley, 1913) (holotype female in BMNH, examined) and Y. luteus ( Cameron, 1899) (holotype female in BMNH, examined), particularly the former, which is also structurally closest. However, the color of the mesoscutum, mesopleuron and metasomal tergite 1 of Y. coronatus sp. nov. differs. In Y. biumbratus the black markings are more restricted, with an entirely yellow metapleuron. In Y. luteus , the median lobe of the mesoscutum is black anteriorly, amongst other differences. In Wang (1993), this new species keys to Yezoceryx apicicarinus Wang. It differs from the latter by the sculpture of the face and the colour pattern of the mesoscutum and mesopleuron. Two females from Papua New Guinea in BMNH (Bulolo, Mankica, 11.xii.1981) are very similar to the type series from Vietnam, differing in minor details of colour pattern, such as the more extensive black markings on the mesopleuron and hind femur; we refrain from including these specimens in the type series. Yezoceryx biumbratus , Y. coronatus sp. nov. and the specimens from Papua New Guinea may conceivably be at the opposite ends of a colour spectrum, from palest in India ( Y. biumbratus ) through to darkest in Papua New Guinea. All these specimens share an apically widened antennal flagellum relative to the slenderer proximal segments. However, we treat these as separate species for now, given the known disjunct range and distinct differences in colour patterns.

We also take the opportunity to note that Yezoceryx luteus (original combination Macrogaster luteus Cameron, 1899 , holotype male in BMNH, examined) is a senior synonym of Acaenitus xanthorius Morley, 1913 (holotype female in BMNH, examined): syn. nov.

Etymology. Named after the crown-shaped black mark on the mesoscutum.

Distribution. Currently known only from Cuc Phuong NP, Ninh Binh Province and Cat Tien NP, Dong Nai Province, Vietnam ( Figure 19 ).

Figures

FIGURE 4. Yezoceryx coronatus sp. nov.: a. lateral view; b. dorsal view; c. face; d. lateral view of mesosoma; e. lateral view of first metasomal tergite; f. lateral view of hypopygium.

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.