Sirex chimera Ge, 2025

3.3.2. Sirex chimera Ge sp. nov.

Figure 11 View Figure 11

Material examined.

Type specimens: 1 ♀ holotype, 6 ♀ 4 ♂ paratypes, Maojingba National Forest Park , Wangyedian Village, Chifeng, Inner Mongolia, 118.23114800E, 41.60897200N, 2022-VII-5 ~15, Bai GD leg. Deposited in Beijing Forestry University GoogleMaps .

Etymology.

This specific epithet alludes to the Greek mythological monster Chimera which combined a lion’s head, a goat’s body and a serpent’s tail, denoting the males of the new species resembling S. noctilio and females resembling S. nitobei .

Diagnosis.

Females with wings largely clear (Fig. 11 A View Figure 11 ); vein 3 A of forewings absent; antennae and legs largely blackish (Fig. 3 A View Figure 3 ); tarsal pad of metatarsomere 2 0.7–0.8 times as long as ventral length of tarsomere (Fig. 7 A View Figure 7 ). Males with antennae completely dark (Fig. 3 B View Figure 3 ); abdomen segments I – III and VIII – IX largely blackish, IV – VII light yellowish (Fig. 10 B View Figure 10 ); metafemur blackish.

Female Description. Color: Body, legs blackish with dark blue metallic reflections (Fig. 11 A, B View Figure 11 ), terga II – VII sometimes with dark purple metallic reflections medially (Fig. 10 A View Figure 10 ). Antennae and palpi blackish (Fig. 3 A View Figure 3 ). Forewings mainly clear, at most tinted with light brown near outer margin. — Head: Genae with pits less than 4.0 pit diameters apart (Fig. 6 A View Figure 6 ); vertex with pits less than 3.0 pit diameters apart (Fig. 5 A View Figure 5 ), and each pit diameter about 0.3 times as lateral ocelli. — Thorax: Mesoscutum with large pits densely developed in median area, transverse ridges vague. Metatarsomere 2 in lateral view about 2.2–2.5 times as long as height, length about 1.0–1.1 times length of tarsomeres 3 + 4; tarsal pad 0.7–0.8 times as long as ventral length of tarsomere (Fig. 7 A View Figure 7 ). Forewings vein 3 A absent. — Abdomen: Median basin of tergum IX with basal width about 1.2 times as long as median length, maximum width about 1.3–1.5 times as long as median length, median length about 0.55–0.65 times of cornus length. Cornus in dorsal view relatively short, with edges straight to slightly angulate midway; its median length 1.05–1.15 times as long as maximum width of abdomen at junction of terga IX and X. Sheath. Basal section about 1.2 times as long as apical section. Ovipositor. Pits near middle annuli (the area at base of apical section of sheath) 0.27–0.30 times as long as an annulus (Fig. 10 A View Figure 10 ), pits scarcely decreasing in size toward ovipositor base, 0.35–0.41 times as high as lancet height in lateral view, 1.0–1.1 times as long as pits height.

Male Description.

Color: Head, thorax and coxae black with dark blue metallic reflections (Fig. 11 C, D View Figure 11 ). Antennae and hind legs blackish (Fig. 3 B View Figure 3 ), except the base of metatibia and metatarsomere 4 yellowish. Fore and middle legs predominantly yellowish, femora blackish at basal half and reddish brown at apical half, metatarsomeres 5 blackish. Forewings tinted with light yellowish and slightly pale brownish near outer margin. Abdomen segments I – III and VIII black with dark blue metallic reflections, terga III and VIII partly yellowish, segments IV – VII light yellowish, sternum IX blackish, rarely with yellowish tone at margins (Fig. 9 B View Figure 9 ). — Thorax: Metatibia 4.0–4.3 times as long as maximum width (Fig. 8 A View Figure 8 ). Metatarsomere 1 in lateral view 3.2–3.4 times as long as maximum height.

Distribution.

Only known from the type locality in Inner Mongolia (Chifeng City)

Host.

Larix gmelinii var. principis-rupprechtii (Mayr.)

Note.

All type specimens of the new species were collected during the same year from a single batch of logs at the local forest station. Both male and female individuals were observed emerging from these logs, as confirmed by the collecting researchers and forest station staff. This co-occurrence supports the association between the male and female specimens. Based on the field investigations conducted by the authors, to date the known distributional range of this new species has only been confined to its type locality. Notably, S. nitobei co-occurs with the new species in the same area, demonstrating two sympatric species (Fig. 19 View Figure 19 ). The niche differentiation of these two species is reflected in their different host plants: S. chimera sp. nov. in Larix spp. and S. nitobei in Pinus spp. Phylogenetic analysis suggests that S. nitobei and S. chimera form sister groups, with each of the monophyletic lineage supported by high posterior probabilities (PP = 100). The observed K 2 P genetic distance of 0.07 between these two taxa, coupled with diagnostic morphological differences, provides conclusive evidence for the status of S. chimera sp. nov., given the current status of knowledge for Sirex . Although the current known distribution of S. chimera remains restricted, its preferred coniferous forest habitat is extensively distributed across northern China.