Siobla acutiserrula, Niu, Gengyun & Wei, Meicai, 2010

Niu, Gengyun & Wei, Meicai, 2010, Revision of the Siobla annulicornis, acutiscutella and sheni groups (Hymenoptera: Tenthredinidae), Zootaxa 2643, pp. 45-65 : 56-58

Siobla acutiserrula sp. nov.

(Plate 6)

Description. Holotype: Ψ.

Body length 12 mm (Figs. 6a, b). Body yellow brown with following black: apex of 3rd antennomere ventrally, venter of 4th antennomere largely, 5 apical antennomeres entirely, a large macula on 5th abdominal tergite, 6th to 10th abdominal tergites and sternites entirely, sheath, a small round spot on posterior side of hind femur apically, apical half of hind tibia; and body hairs yellow brown. Wings yellowish hyaline, with a large smoky macula at apex, inner margin of macula convex and reaching1r-m, vein C and stigma yellow brown, other veins blackish brown.

PLATE 5. Siobla acutiscutella Wei & Nie, 1999 . (a). Female adult in dorsal view; (b). Female adult in lateral view; (c). Head of female in dorsal view; (d). Head of female in frontal view; (e). Mesonotum in lateral view; (f). Sheath in lateral view; (g). Lancet; (h).Middle serrulae.

Clypeus with large and sparse punctures, malar space microsculptured, other parts of head densely punctured, without shiny interspaces, matt; propleuron, most of metapleuron, and appendage of mesoscutellum strongly shiny, without distinct punctures and microsculpture pronotum rugose, mesoscutum densely punctured, feebly shiny; mesoscutellum, metascutellum, and elevated part of mesepisternum densely and coarsely punctured, without distinct interspaces, matt; anterior, posterior and venter of mesepisternum sparsely punctured, shiny; mesepimeron densely and finely microsculptured; upper margin of metepisternum feebly punctured, shiny, other parts of metapleura strongly shiny; first abdominal tergite without microsculpture, shiny; other tergites indistinctly microsculptured, apical 5 tergites with shallow and sparse punctures.

Anterior margin of clypeus truncate, without middle incision, lateral corner almost rectangular; inner margins of eyes distinctly convergent, shortest distance between eyes 1.14 times eye height; malar space as long as diameter of ocellus (Fig.6e); middle fovea large and deep, merging with frontal basin; lateral fovea small; supra-antennal tubercles slightly elevated, narrow, connected to fine and sharp frontal ridge; interocellar furrow shallow, postocellar furrow indistinct; lateral furrows deep, straight, parallel to each other posteriorly; postocellar area slightly elevated, lower than top of ocelli, without middle carina, wider than long as 7: 6; head behind eyes distinctly shorter than eye in dorsal view, lateral sides curved, distinctly convergent posteriorly; occipital carina sharp, complete. Antenna slightly longer than abdomen, relative lengths of third to fifth antennomeres as 44: 27: 25, fifth to eighth antennomeres slightly dilated, compressed, inner and outer sides of each with a distinct furrow. Mesepisternum angularly elevated, with distinct corner; mesoscutellum strongly elevated, much higher than top of scutum, apex acute, anterior slope convex, posterior slope perpendicular (Fig. 6i); appendage elevated, without middle carina. Metabasitarsomere as long as following 4 tarsomeres together. Hairs on temple and mesoscutellum sparse, shorter than diameter of ocellus. Ovipositor longer than metabasitarsomere as 9: 8, sheath slender in lateral view (Fig. 6g). Lancet long and slender, with 12–14 serrulae, middle serrulae each with 1 inner and 5–6 outer subbasal teeth, apical 3 to 4 serrulae continuous (Figs. 6j, k).

PLATE 6. Siobla acutiserrula sp. nov. (a). Female adult in dorsal view; (b). Female adult in lateral view; (c). Male adult in dorsal view; (d). Male adult in lateral view; (e); Head of female in frontal view; (f). Head of male in frontal view; (g). Sheath in lateral view; (h). Head of male in dorsal view; (i). Mesonotum in lateral view; (j). Lancet; (k). Middle serrulae; (l). Penis valve; (m). Harpe and parapenis.

Male: Body length 10–11 mm (Figs. 6c, d). Body black, scape, pedicel, dorsum of 3rd and 4th antennomeres, basal 3rd of 3rd antennomere ventrally dark reddish brown; mouthparts yellow brown, apex of mandible and most of labium black; apical half of clypeus, broad posterior margin of pronotum, tegula, mesoscutellum and appendage, metascutellum and lateral carinas, posterior 2/3 of first abdominal tergite, 2nd and 3rd tergites entirely, anterior half of 4th tergite, and 2nd to 5th abdominal sternites yellow brown; legs yellow brown, most of coxae, base and apex of middle femur dorsally, broad stripe on dorsum of hind femur, extreme base and apical half of hind tibia black, trochanters and tarsus pale yellow brown. Wings indistinctly grayish, hyaline, apical 1/3 distinctly infuscate, vein C and stigma yellow brown, other veins black. Body hairs pale brown. Punctation and structure similar to female except as follows: malar space hardly as long as radius of ocellus, shortest distance between eyes slightly narrower than eye height; head in dorsal view slightly convex behind eyes and then distinctly narrowed, slightly longer than half length of eye (Fig. 6f); subgenital plate as long as wide, apex round; genitalia as in Figs.6l, m.

Variability: The ventral part of the mesepisternum in 5 female specimens is black; the postocellar area in one male has a brown spot.

Etymology: The specific epithet refers to the acute serrulae of the female lancet.

Specimens examined: Holotype: Ψ, Leidongping, Mt. Emei, Sichuan (29°32.476´N, 103°19.890´E), alt. 2400m, 26 July 2006, WEI Mei-Cai leg.; paratypes: 3 ΨΨ, same data as for holotype., 4 ɗɗ, Leidongping, Mt. Emei, Sichuan (29°52.42´N, 103°34.03´E), alt. 2045m, 12 June 2007, ZHANG Shao-Bing, LIU Fei leg.; 4 ΨΨ, Leidongping, Mt. Emei, Sichuan (29°54.6´N, 103°32.7´E), alt. 2350m, 7–8 July 2009, WEI Mei-Cai, LI Ze-Jian leg.

Distribution: China (Sichuan).

Remarks: The new species is similar to S. weni ., but differs from it by the slender body; clypeus subtruncate at apex, without middle incision; the peak of the mesoscutellum acute; the shortest distance between eyes longer than eye height in female; lancet slender and with 12–13 serrulae, the middle serrulae each with 1 inner subbasal tooth and 5–6 outer subbasal teeth; in male, the head except mouthparts black, the anterior margin of mesoscutellum and scutum entirely black; the lower parts of volsella and gonolacinia small.