Siobla takeuchii Shinohara, Wei & Niu

Shinohara, Akihiko, Wei, Meicai & Niu, Gengyun, 2013, Revision of Siobla (Hymenoptera, Tenthredinidae) from Japan, Zootaxa 3746 (1), pp. 1-40 : 22-26

publication ID 10.11646/zootaxa.3746.1.1

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Siobla takeuchii Shinohara, Wei & Niu

sp. nov.

Siobla takeuchii Shinohara, Wei & Niu , sp. nov.

( Figs 3c–d View FIGURE 3. a – d , 5 View FIGURE 5 s–t, 6i, 7i, 8i, r, 10c, 11a–d) Description. Female. Holotype ( Figs 3c View FIGURE 3. a – d , 5 View FIGURE 5 s). Length 15.0 mm. Body black, apical 0.65 of antennomere 2, antennomeres 3 and 4 entirely, antennomere 5 except extreme apex, palpi, narrow posterior margin of pronotum, narrow anterior margin of tegula, spots on both lateral sides of abdominal tergum 1, abdominal tergum 9 largely, abdominal tergum 10, apex of sheath, and cerci pale brown; abdominal terga 2 and 3 and sterna yellow brown. Legs black, apical 0.25 of fore femur, anterior stripe and apical 0.2 of middle femur, fore and middle tibiae and tarsi, hind trochanter, basal 0.25 of hind femur, basal 0.65 of hind tibia, and entire hind tarsus yellow brown. Hairs on dorsum of head and of thorax yellow brown, hairs on pleuron silver. Fore wings yellowish hyaline, vein C and stigma pale brown, cell Sc infuscated; hind wings hyaline.

Dorsum of head densely punctured, frons coarsely punctured, matt; upper part of inner orbit, temple and postocellar area densely punctured without interspaces, feebly shiny. Most of propleuron sparsely punctured; mesonotum sparsely punctured, with narrow shiny interspaces; mesoscutellum densely punctured without interspaces, feebly shiny, with posterior slope coarsely punctured, matt; mesoscutellar appendage shiny at middle; punctures on middle of mesepisternum large and dense, without interspaces, punctures on anterior and posterior margins of mesepisternum sparse, punctures on ventral part of mesepisternum shallow and sparse, interspaces feebly microsculptured, shiny; part of katepimeron densely microsculptured but anterior and posterior margins shiny; metapostnotum microsculptured; metepisternum with dorsal part densely punctured and ventral part of shallowly and sparsely punctured; most of metepimeron microsculptured, rest shiny except dorsal part densely punctured. Abdominal tergum 1 with a few shallow punctures along anterior margin and on lateral sides, shiny; terga 2 and 3 shiny, terga 4 to 9 faintly microsculptured, with lateral sides shallowly punctured.

Hairs on dorsum of head and of thorax slightly longer than diameter of median ocellus, straight; hairs on mesopleuron slightly longer than diameter of median ocellus, hardly curved. Clypeus 2.0 × as broad as long, anterior margin weakly protruding; malar space 0.6× diameter of median ocellus; lower interocular distance 1.1 × eye height ( Fig. 11c View FIGURE 11. a – d ); middle fovea small, about as deep as lateral fovea; interocellar furrow wide and deep; postocellar furrows shallow; postocellar area weakly elevated, as high as ocelli, with fine and low middle carina, about 1.4 × as broad as long; lateral furrows deep, slightly curved in middle, nearly parallel posteriorly; temple 0.6 × length of eye in dorsal view, anterior 0.25 curved, rest divergent backwards ( Fig. 11a View FIGURE 11. a – d ). Antenna about 0.9× as long as vein C of forewing, antennomere 2 longer than broad, antennomere 3 1.7 × as long as antennomere 4, subapical antennomeres weakly enlarged; antennomere 7 2.0 × as long as broad. Middle furrow on pronotum narrow; mesoscutellum roundly elevated, slightly higher than top of mesoscutum, without carina or acute apex; mesoscutellar appendage almost flat, without middle carina; mesepisternum obviously elevated, ventral spur absent. Hind inner tibial spur 0.5 × length of metabasitarsus; metabasitarsus 5 × as long as broad, 1.1 × length of following 3 tarsomeres combined; pulvilli small, distance between basal two pulvilli 4.5 × length of second pulvillus. Ovipositor sheath 0.9 × length of middle tibia, apical sheath 1.4 × length of basal sheath; lancet as in Fig. 6 View FIGURE 6 i; middle serrulae as in Fig. 7 View FIGURE 7 i.

Male. Paratype from Asahidake-onsen. Length 11.5 mm ( Figs 3d View FIGURE 3. a – d , 5 View FIGURE 5 t). Colour and structure similar to female except as follows: Pale line along posterior margin of pronotum extremely narrow; tegula entirely black; most of trochanter black, with broad apical margin whitish; trochantellus largely black; hind femur black except for wide stripe on anterior surface pale brown; antenna with antennomere 2 entirely black and antennomeres 3 to 5 marked with black ventrally; malar space 0.2 × diameter of lateral ocellus; shortest distance between eyes 0.8 × as long as height of eye; temple about 0.6 × eye length in dorsal view ( Fig. 11b View FIGURE 11. a – d ); hairs on dorsum of head, dorsum of mesoscutellum, and pleuron 1.3 × as long as diameter of median ocellus, hairs on pleuron distinctly curved. Subgenital plate longer than broad, apical margin rounded ( Fig. 11d View FIGURE 11. a – d ); valviceps narrow ( Fig. 8 View FIGURE 8 r); gonoforcep as Fig. 8 View FIGURE 8 i.

Etymology. This species is named in honour of the late K. Takeuchi, who made a pioneering contribution to the sawfly systematics in East Asia.

Distribution. Japan (Hokkaido, Honshu, Kyushu).

Holotype ( Figs 3c View FIGURE 3. a – d , 5 View FIGURE 5 s): ♀, Ashiu-enshurin, Miyama-cho, Kyoto, Honshu, 11. VI. 1989, K. Mizuno, NSMT-I- HYM 65836, genitalia slide N20130906B (NSMT). Paratypes: 165 specimens (57♀ and 108♂, see Appendix).

Variation. The length varies from 11.0 to 15.5 mm in the female and 9.5 to 13.0 mm in the male. The colouration of the antenna shows large variation, but the apical four or five antennomeres are always black and the scape and pedicel are usually partly or entirely black in both sexes. The other antennomeres are usually mostly or entirely brown, though the antenna is almost entirely black in very dark specimens. In the female, the mesoscutellum often has an obscure brownish spot medially, the hind trochanter is sometimes marked with black ventrally, and the abdominal terga 2 and 3 are often marked with black. In the male, the pale line along the posterior margin of the pronotum may be missing, the hind trochanter and trochantellus are always marked with black, the abdominal terga 2 (except for the narrow anterior margin) and 3 are always yellow brown, and the tergum 4 is often yellow brown at base. The ranges of some ratio variations are given in the key.

Remarks. Siobla takeuchii is a member of the S. formosana group defined by Niu & Wei (2010), though the males could run to the S. sturmii group or to the S. ferox group in the key (Niu & Wei 2010). The new species closely resembles S. hirasana Takeuchi, 1929 , belonging to the S. ferox group. In the female, S. takeuchii has the anterior margin of the clypeus weakly protruding ( Fig. 11c View FIGURE 11. a – d ), the labrum dark brown basally, the posterior margin of the pronotum, tegula, and mesoscutellum usually entirely black (mesoscutellum rarely with small obscure spot medially), the metabasitarsus equal in length to the following three tarsomeres combined, hind trochanter sometimes marked with black, and the sawsheath black, except at apex. The female of S. hirasana has the anterior margin of the clypeus nearly truncate ( Fig. 11 View FIGURE 11. a – d g), the labrum whitish basally, the broad posterior margin of pronotum, tegula, and mesoscutellum always mostly yellowish brown, the hind trochanter never marked with black, and the sawsheath entirely pale brown. In the male of S. takeuchii , the tegula and mesoscutellum are entirely black, the hind trochanter and trochantellus are usually largely blackish brown or black, and the subgenital plate is narrowly rounded at apex ( Fig. 11d View FIGURE 11. a – d ), whereas in S. hirasana the tegula and mesoscutellum are largely yellowish brown, the hind trochanter and trochantellus are usually entirely whitish brown, rarely partly marked with blackish brown, and the subgenital plate is broadly rounded at apex ( Fig. 11 View FIGURE 11. a – d h). The two species also differ in the shape of the head in dorsal view ( Fig. 11a–b View FIGURE 11. a – d , e–f).

Takeuchi’s (1919b) description of “ Siobla ruficornis Cameron ?” was based on an unknown number of specimens from Yoshino, Nara prefecture, and two male specimens from “Shinano” (=Nagano prefecture). Two pairs of S. takeuchii collected in Yoshino in 1916 and kept in Takeuchi’s collection in OPU agree with the description of “ Siobla ruficornis Cameron ?” by Takeuchi (1919b) and should belong to his original material. Takeuchi (1919b, p. 14) noted that the two male specimens from “Shinano” differed from the Yoshino specimens in that the antenna was yellowish brown except for the basal three antennomeres and in that the yellowish brown parts of the body were more reddish. We were not able to locate those two males in Takeuchi’s collection but they probably belong to S. sturmii because of the colour pattern of the antenna and the hind femur.

The male specimen of “ S. ferox ” shown by Esaki et al. (1939) in their figure 592 2 in plate 152 has apically black antenna and entirely black dorsum of the thorax. This specimen was not available for the present study but it most probably belongs to S. takeuchii , because S. ferox has the apex of the antenna usually brown, though sometimes darkened, and has the dorsum of the thorax and the abdominal tergum 1 largely marked with pale brown. Togashi’s (1955) figure of the penis valve of “ S. ferox ” agrees most closely with that of S. takeuchii . Some specimens cited as S. ferox by Naito (1982) and Naito et al. (2004) and those listed under S. sturmii and Siobla sp. D by Katayama (2004) also belong to the present new species (see Appendix).













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