Spilopteron tumidium, Pham & Broad & Matsumoto & Achterberg, 2019

Pham, Nhi Thi, Broad, Gavin R., Matsumoto, Rikio & Achterberg, Cornelis Van, 2019, First records of the genus Spilopteron Townes (Hymenoptera: Ichneumonidae: Acaenitinae) from Vietnam, with descriptions of five new species, Zootaxa 4590 (1), pp. 153-165 : 162-164

Spilopteron tumidium sp. nov.

( Fig. 7 )

Material examined. Holotype: ♀ ( IEBR), Lang Son, Mau Son, 15.v.2013, hand net, D.D. Tran leg.

Description of holotype female. Head. Antenna with 35 flagellomeres, first flagellomere 1.2× length of second; frons concave and polished medially, punctate laterally, carina between antennal sockets extending to face dorsally; face 0.7× as high as wide, densely, shallowly punctate, medially distinctly swollen; clypeus about 0.4× as high as wide, subpolished, with small punctures, median tubercle small; malar space equal to basal width of mandible; exposed part of labrum about 0.6× as long as basal width; lower tooth of mandible longer than upper; inner margins of eyes divergent ventrally; diameter of lateral ocellus 0.5× ocellar-ocular distance; vertex with dense, small punctures; occipital carina evenly curved, ventrally meeting hypostomal carina about 0.8× basal mandible width from base of mandible.

Mesosoma. Epomia absent; pronotum with striations across median groove and punctures at posterior corner; mesoscutum 0.9× as long as wide at anterior level of tegulae, with dense punctures, pubescent, median and lateral lobes medially slightly concave, anterior face of mesoscutum high and steeply rising at nearly 90° to pronotal collar; scutellum densely punctate, pubescent, lateral carina present basally; metanotum polished, impunctate; mesopleuron with dense, small punctures, pubescent, epicnemial carina extending to subtegular ridge but interrupted subdorsally; metapleuron matt, with dense, small punctures, pubescent, submetapleural carina indistinct medially; propodeum with area basalis smooth, longer than wide, area externa densely punctate, pubescent, area dentipara well defined and with wrinkles, area petiolaris polished, impunctate; fore basitarsus 2.1× second tarsomere; mid basitarsus 2.3× second tarsomere; hind leg with femur 3.75× as long as wide, 0.67× length of tibia, tarsus 0.8× tibia, basitarsus 2.4× second tarsomere, fifth tarsomere 1.6× longer than third. Fore wing length 11.4 mm, vein M&RS distad of 1 cu-a, vein 2 rs-m distad of 2 m-cu by about 0.55× length of 2 rs-m, hind wing with first abscissa of vein CU 0.8× length of vein cu-a.

Metasoma. Tergites with small punctures, pubescent; first tergite 3.0× as long as posterior width, with sparse punctures, lateral longitudinal carina present anteriorly, not extending to spiracle; second tergite 0.4× as long as first tergite, wider than long, slightly longer than third, with dense, small punctures except distal part impunctate; sclerotized part of first sternite not extending to level of spiracle, reaching 0.7× length of tergite; ovipositor sheath 1.7× as long as hind tibia; hypopygium 2.9× as long as second tergite.

Colour. Black with yellow as follows: flagellomeres 12 to 22, face (but black medially), inner orbit, clypeus, mandible teeth (except distal ends), labrum, gena, scutellum, metanotum, posterior end of propodeum, longitudinal band on anterior part and a spot at posterior end of first metasomal tergite, roughly triangular marks at posterior ends of second and third tergites and posterior margins of following tergites, hypopygium and ovipositor, fore and mid legs except fifth tarsomeres, hind trochanter, proximal part of hind femur, proximal 0.7 of hind tibia, hind tarsus. Fore wing with apical margin infuscate.

Male. Unknown.

Comparison. In general appearance, Spilopteron tumidium sp. nov. resembles S. flavescutatum Wang, 2004 . It differs from the latter by the swollen face, the colour pattern of the metasomal tergites (with more yellow markings), the broader tubercle on the first sternite, and its shorter ovipositor sheath (1.7× length of hind tibia vs 2.6×).

Etymology. This species is named after its medially swollen face.

Distribution. Currently known only from Mau Son District, Lang Son Province, Vietnam.

Figures

FIGURE 7. Spilopteron tumidium sp. nov. holotype female: a. habitus, lateral view; b. face; c. dorsal view of head and mesoscutum; d. lateral view of head and mesosoma; e. dorsal view of propodeum; f. wings; g. first tergite.