Siobla jucunda Mocsary 1909

Siobla jucunda (Mocsáry, 1909)

(Figs 2 c–d, 4d–f, 5k–l, 6e, 7e, 8e, n, 10h)

Encarsioneura jucunda Mocsáry, 1909, p. 15.

Siobla sturmii: Takeuchi, 1931: 31 (in part?); Togashi, 1955: 26; Takeuchi, 1956: 77 (in part); Togashi, 1965: 246 (in part), plate 123, 30; Okutani, 1982: 411; Naito, 1982: 574; Katayama, 2004: 96 (in part); Yoshida, 2006: 91; Togashi, 2008: 490 (in part), plate 142, 2538. Not Klug (1817).

Siobla similis var. jucund a: Malaise, 1934: 26.

Siobla ruficornis: Takeuchi, 1936: 85 (in part); Takeuchi, 1952: 18; Abe and Togashi, 1989: 555; Togashi, 1997a: 3; Togashi, 2002a: 9. Not Cameron (1876).

Siobla pacifica: Takeuchi, 1936: 86 (in part). Not Smith (1874).

Siobla jucunda: Taeger et al., 2010: 583; Niu & Wei, 2010: 50.

Distribution. Japan (Hokkaido, southern Kuriles, Honshu, Shikoku), Russia (Primorskiy kray; Sakhalin). New records for Japan and Sakhalin.

Primary type examined. Lectotype of Encarsioneura jucunda hereby designated (Fig. 4 d–f): ♂, “Ussuri, Kasakewitsch, 1907, Korb” “ Encarsioneura jucunda det. Mocs.” “ Encarsioneura jucunda Mocs.” “DEI-GISHym 1003” (HMNH).

Other material examined (see Appendix). 614 specimens (213♀ and 401 ♂).

Variation. The length varies from 10.5 to 15.0 mm in the female and 9.0 to 12.5 mm in the male. This species shows some variation in colouration. In the female, the black areas on the basal three antennomeres may be reduced but are always present. The hind femur is always entirely black. The abdomen sometimes has only the tergum 2 brown. In the male, the basal three antennomeres (except for apex of the third) are usually black, but sometimes the base of antennomere 4 is also marked with black. Normally, abdominal terga 2 to 4 and the base of 5 are reddish brown, but in very dark specimens, only terga 2 and 3 are partly marked with reddish brown. The ranges of some ratio variations are given in the key.

Remarks. Among the Japanese congeners, this species is recognized by the entirely black head and thorax, the pale brown antenna, with the scape, pedicel and flagellomere 1 (except for the apical part) usually mostly black, and the entirely black coxa, trochanter, trochantellus and femur of the hind leg. See the foregoing key for more details.

Siobla jucunda belongs to the S. sturmii group (Niu & Wei 2010) and has often been mixed with and misidentified as S. sturmii or S. ruficornis by Japanese authors. The female specimen identified as S. sturmii by Togashi (1965) and shown in his fig. 30, Plate 123 (also 2538 in Plate 142 in Togashi, 2008), has the antenna reddish brown with the basal three antennomeres black. This specimen was not available for study but it most probably belongs to S. jucunda, not S. sturmii, which has mostly brown basal three antennomeres. Nambu (1992, 1998) and Naito et al. (2004) referred to “ S. ruficornis ”, which may include S. jucunda.

Mocsáry (1909) described Encarsioneura jucunda based on an unknown number of specimens and did not designate types. Niu studied the type material kept in HMNH and found only one male specimen identified as E. jucunda by Mocsáry (Fig. 4 d–f). It bears a red label without letters (Fig. 4 d), which usually indicates type status in Mocsáry’s collection. We hereby designate this male specimen as lectotype for the sake of stability.