Piogaster daisetsuzana Kusigemati, 1985

Figs 7, 8, 9, 10

Piogaster daisetsuzana Kusigemati, 1985: 583.

Diagnosis.

Piogaster daisetsuzana females can be distinguished from congeners by any of the following: 1) propodeum with medial transverse striations (Fig. 8 D) (absent in all other species), 2) FW vein Rs + M with ramellus extending anteriorly into cell 1 M + 1 R 1, tubular for 0.1–0.6 × as long as vein 2 rs-m, and extending farther as nebulous or spectral vein (Figs 7 A, 8 F) (absent or present as only a very short stub in other species), and 3) FW vein 2 m-cu slightly thickened and angulate between bullae (Fig. 8 F) (of uniform thickness and lacking angulation in all other species). Males can be distinguished from other male congeners by a combination of the following: 1) propodeum with medial transverse striations (Fig. 10 D), and 2) presence of a polished, smooth medial part of metapleuron without microsculpture or setae (Fig. 10 C) (some sculpture and / or setae in this region in other males, e. g., Fig. 25 D).

In addition to these morphological characters, there is a binary diagnostic molecular character in the COI barcode sequence of P. daisetsuzana at site 290 (T in P. daisetsuzana, A in other Piogaster), corresponding to amino acid 97 (Leucine in P. daisetsuzana, Methionine in other Piogaster).

Redescription.

Adult. Female. Body length 4.7–6.0 [5.0] mm. FW length 4.1–4.8 [4.1] mm. Head. Antennae with 23–24 [23] flagellomeres. Clypeus 1.6–2.0 [1.7] × as wide as high, subpolished (Fig. 7 C), weakly rugulose in most specimens [smoother in holotype] and sparse, setiferous punctures with long white setae. Face, frons and vertex matte and granulate, with dense, short, yellow-white setae (Figs 7 C, 7 D). Occipital carina weak but complete in some specimens (Fig. 7 D), apparently obsolete dorsally in some specimens [based on original description of holotype] (Fig. 7 B). MSL 0.8–1.1 [1.1] × as long as BWM. OOD 1.7–2.3 [2.3] × as long as LOD. Mesosoma. Pronotum with epomia as a short, low, vertical carina in dorsolateral pronotal groove (Fig. 8 A). Pronotum (Fig. 8 A) and scutellum (Fig. 7 B) matte and rugose, with dense short yellow-white setae. Mesoscutum matte, densely rugulose-punctate to rugose-punctate, with dense short yellow-white setae (Fig. 7 B). Mesopleuron and metapleuron matte, rugose with dense medium length yellow-white setae (Fig. 7 A). Propodeum matte, rugose with medial transverse striations, with dense long yellow-white setae (Fig. 8 D). Propodeum with pleural carina complete, but weak; lateral longitudinal carinae present in posterior 0.3–0.4, all other propodeal carinae absent. Fore wing. Vein Rs + M with ramellus extending into 1 M + 1 R 1 (discocubital) cell as a tubular vein for 0.1–0.6 × as long as 2 rs-m, and then continuing further as nebulous or spectral vein. Vein 2 rs-m 0.5–0.6 [0.6] × as long as M between 2 rs-m and 2 m-cu. Vein 2 m-cu thickened and angulate between bullae (Fig. 8 E). Hind wing. Vein 1 / Cu & cu-a inclivous, angled apically where 2 / Cu intercepts (Fig. 8 E), 2 / Cu intercepting in lower 0.3–0.5 [0.5], 2 / Cu tubular or nebulous at least 0.7 length to posterior edge of wing, reaching posterior edge of wing in some specimens. Metasoma. T 1 matte, with dense, setiferous punctures, punctate reticulate laterally and in some specimens medially, with dense, short, yellow setae (Figs 7 B, 8 G). T 1 median dorsal carina present anteriorly, but weak and short, 0.1–0.3 [0.2] × length of T 1; dorsolateral carinae complete (Fig. 8 C). T 2 – T 5 subpolished, with dense, setiferous punctures, space between punctures less than 0.5 × puncture diameter, laterally punctate reticulate with dense short to medium length yellow-white setae (Figs 7 B, 8 H). T 6 subpolished, finely punctate, with dense short white setae. T 7 and T 8 subpolished, sparsely, finely punctate with dense medium length white setae. Tergites without grooves or tubercles. Ovipositor sheath 0.9–1.2 [1.2] × as long as hind tibia. Colour. Head (Figs 7 A – D) yellow to yellow-white, lighter ventrally (clypeus and face and gena), frons tinged with light brown in some specimens. Vertex uniformly yellow, lacking sublateral lighter-coloured mark present in other Piogaster species (Figs 7 B, 7 D). Occiput yellow near occipital carina, light brown medially. Mandible basally yellow, apically dark brown-black. Maxillary and labial palps uniformly pale yellow. Antenna uniform yellow-brown or yellow basally and dark brown apically [as in holotype] (Fig. 7 A). Pronotum yellow-white to yellow dorsally, tinged with pale brown medially and ventrally in most specimens [including holotype] (Fig. 7 A). Tegula yellow to light brown [light brown] (Fig. 7 A). Mesoscutum medium brown, with yellow submedial and sublateral longitudinal stripes (Fig. 7 E). Scutellum light to medium brown, pale yellow to light brown anteriorly, axillary troughs medium brown (Fig. 7 E). Post-scutellum light to medium brown, axillary troughs yellow. Mesopleuron yellow-white / yellow to brown-yellow, paler in ventral third in most specimens, especially anteriorly [“ pale yellow spot on anterior lower corner ”] (Fig. 7 A). Metapleuron and propodeum uniformly yellow to brown-yellow. Wings hyaline to subhyaline, veins light to medium brown, SC + R medium to dark brown. Legs yellow to yellow brown, with medium brown longitudinal stripe on dorsal and / or ventral of fore, middle, and / or hind femora and tibiae, these longitudinal stripes ranging from poorly to well-defined [holotype with femoral stripes poorly defined, tibial stripes well defined (Figs 7 A, 7 B)]; all leg segments paler on anterior and posterior surfaces; tarsi a bit darker than other segments. Metasomal tergites yellow to medium brown, T 2 – T 6 pale yellow posteriorly in most specimens [including holotype (Fig. 7 A)]. Ovipositor sheaths uniform yellow-white.

Male. Body length 5.4–6.1 mm. FW length 4.5–5.2 mm. Head. Antennae with 24 flagellomeres. Clypeus 1.6–2.0 × as wide as high, smooth, polished with sparse setiferous punctures, with medium brown long setae. Face polished, smooth with sparse setiferous punctures, with sparse short yellow setae (Fig. 9 C). Frons and vertex polished, with moderately dense setiferous punctures, short yellow-white setae (Figs 9 C, 9 D). Occipital carina complete (Fig. 9 D). MSL 0.7 × as long as BWM. OOD 1.2–1.7 × as long as LOD. Mesosoma. Pronotum with epomia present in dorsolateral pronotal groove, short (Fig. 10 A); polished, punctate dorsally with dense medium length white setae, smooth ventrally and lacking setae (Fig. 10 A). Mesoscutum subpolished, densely punctate, with dense medium length white setae (Fig. 9 E). Scutellum polished, punctate, with dense long white setae (Fig. 9 E). Mesopleuron polished, punctate with moderately dense medium length white setae, posterodorsally smooth without setae (Fig. 10 B). Metapleuron polished, margins with sparse, setiferous punctures and moderately dense long white setae, medially smooth and lacking setae (Fig. 10 C). Propodeum rugose punctate with medial transverse striations, with dense long white setae (Fig. 10 D). Propodeum with pleural carina complete (Fig. 10 C); lateral longitudinal carina present posteriorly, extending anteriorly to 0.8 × length of propodeum; median longitudinal carinae present anteriorly (Fig. 10 D), extending posteriorly to 0.5–0.6 × length of propodeum. Wings. Fore wing. Vein Rs + M with ramellus extending into 1 M + 1 R 1 (discocubital) cell as a tubular vein for 0.8–1.1 × length of 2 rs-m, continuing across 1 M + 1 R 1 cell as a nebulous and / or spectral vein (Fig. 10 E). Vein 2 rs-m 0.5 × as long as M between 2 rs-m and 2 m-cu (Fig. 10 E). Vein 2 m-cu not thickened or angulate between bullae (Fig. 10 G). Hind wing. Vein 1 / Cu & cu-a slightly inclivous, in most specimens angled apically where 2 / Cu intercepts in lower 0.3–0.4, tubular basally and nebulous apically, extending 0.7–0.8 to edge of wing (Fig. 10 F). One wing of one specimen with vein 1 / Cu & cu-a inclivous, not angled, vein 2 / Cu present, but not intercepting vein 1 / Cu & cu-a. Metasoma. T 1 polished, strongly, densely punctate reticulate, with dense, medium length, white setae (Fig. 10 H). T 1 median dorsal carinae present, 0.4 × length of T 1, bordering the medial basal sulcus; dorsolateral carina complete. T 2 – T 4 each with a weak medial to posterior transverse groove; coarsely, densely punctate reticulate with dense, medium length, yellow setae anterior to groove, sparsely punctate and polished with sparse, medium length, yellow setae posterior to groove. T 5 more polished than anterior tergites, densely punctate to punctate reticulate anteriorly, densely, finely punctate with dense medium length yellow setae posteriorly (Fig. 10 H). T 6 – T 8 polished with sparse punctation with dense, medium length, yellow setae (Fig. 10 H). Colour. Frons and gena dark brown to black, with clypeus and medial face medium brown (Figs 9 C, 9 D). Vertex and occiput uniformly black (Fig. 9 D) or vertex black with white-yellow small ovoid mark (Fig. 9 B). Mandible brown-yellow with longitudinal dark brown stripe or dark brown and apically brown-yellow. Maxillary and labial palps yellow basally, light to medium brown apically (Fig. 9 A). Antenna dark brown, first 13–14 antennomeres pale yellow ventrally (Figs 9 A, 9 B). Mesosoma (Figs 9 E, 10 A – D) dark brown to black except for the following: pronotum with brown-yellow dorsoposterior corner (Fig. 10 A), tegula yellow-white (Fig. 10 A). Wings hyaline, veins medium brown (Figs 10 E, 10 F). Fore and middle leg including coxa pale yellow, except tibiae with dorsal, longitudinal, pale brown stripe. Apical three tarsomeres of fore leg yellow brown, middle tarsus dark yellow brown, except basal tarsomere yellow laterally. Hind leg yellow brown, except coxa light brown, trochanter and trochantellus light brown dorsally, femur laterally between 0.1–0.8 light brown, tibia with brown, dorsal stripe in basal 0.2 and apical 0.3, tarsus brown dorsally, yellow brown ventrally (Fig. 9 A). Metasomal tergites uniformly dark brown to black (Figs 9 A, 10 H).

Distribution.

Fig. 27. Japan: Hokkaido (Kusigemati 1985), Kyushu (Matsumoto 2016), and Honshu (Watanabe and Yamauchi 2018).

Biology.

Host unknown.

Material examined.

Holotype. Japan • ♀; Hokkaido, Mt. Daisetsn [Mt. Daisetsu]; 29. vii. 1967; K. Kusigemati; [EIHU].

Condition of holotype: Missing left fore wing and hind wing, otherwise intact (Digital images analyzed, Figs 7 A – C).

Other material.

Japan • 1 ♀; Hokkaido, Chitose, stream near Shikotsu-tunnel; 42.7048°N, 141.2910°E; 17. viii – 1. ix. 2012; N. Kuhara; Malaise trap; CNC 1754518; [EUMJ] • 1 ♀; Kyushu, Fukuoka, Sefuriyama c.; 6. vi. 1995; R. Matsumoto; NHMUK 015215320; [NHMUK] • 1 ♀; same data as for preceding; NHMUK 012850731; [NHMUK] • 1 ♀; same data for preceding; 16. vi. 1995; R. Matsumoto; CNC 310409; [NMS] • 1 ♀; Kameya, Toyama City; 1–8. ix. 2009; [Kanagawa Prefectural Museum of Planet Earth and Life] (photo only) • 1 ♂; Honshu, Kansai, Osaka, Kishiwada, near Izumi-Katsuragisan; 30. vi – 13. vii. 2002, R. Matsumoto; Malaise Trap 3 (A); CNC 310410; [NMS] • 1 ♂; same data for preceding; 2–13. v. 2002; R. Matsumoto; Malaise Trap 2 (C); NHMUK 015215321; [NHMUK].

Comments.

In the original description of P. daisetsuzana, Kusigemati (1985) states that the diagnostic features of this species are the presence of an epomia, a wide malar space, and antennae with 25 segments. In this study, four additional female specimens and two additional male specimens were examined that have made these features no longer diagnostic. Malar space and antennal segments now overlap with other species. While we have not examined the holotype specimen in person and thus have not seen the epomia on that specimen, we have seen what appears to be a short, weak to indistinct epomia in two specimens (as in Fig. 8 A). Verification of its presence in other species is complicated by the presence of rugose sculpture in this area (Fig. 14 A) and the angle of the head which obscures the area in several specimens. As such, we have not included it as a diagnostic character for P. daisetsuzana. The male P. daisetsuzana we examined have a short epomia (Fig. 10 A), but other males from Europe (example: BOLD ProcessID BIOUG 17116 - B 03) have been examined with a similar epomia, so this is not diagnostic for male P. daisetsuzana.

This is the first time the male of P. daisetsuzana has been described. Two P. daisetsuzana males were examined morphologically, and one was barcoded and included in the COI phylogeny. This male clustered in a monophyletic clade with two female P. daisetsuzana (Figs 1, 2) and its COI sequence was only 0.11–0.14 % divergent from these two females. In addition, males and females share diagnostic morphological features (see Diagnosis). Finally, P. daisetsuzana is geographically isolated from all other Piogaster species (only recorded from Japan: Fig. 27).

Sexes differ in some diagnostic characters. First, males do not have a FW 2 m-cu slightly thickened and angulate between bullae (Fig. 10 E) as in females (Fig. 8 E). Second, while male P. daisetsuzana have a longer extension of the FW ramellus than females (tubular and 0.75–1.1 × length of 2 rs-m) (Fig. 10 E) we have examined two males from Italy (presumably not P. daisetsuzana because of the locality) that have an extension of the FW ramellus up to 0.9 × as long as 2 rs-m, so this character is also not diagnostic for male P. daisetsuzana.

In the original description, Kusigemati (1985) reported T 3 of the female as 2.2 × as long as wide. However, this is an error, as T 3 is much wider than long in all female specimens examined including the holotype based on the photos of this specimen (Fig. 7 A, B). Additionally, Kusigemati (1985) described the head as pale yellow and the mesosoma as yellowish-brown to light infuscate. The photos of the holotype (Fig. 7 A, B) appear to have a brighter yellow head and the mesosoma has areas of orange, but this is likely an artifact of the photographic settings (e. g., lighting, white balance) which produced a more saturated image. In Fig. 7 C, however, the head of the holotype appears closer to the pale yellow from the original description.