Homoeusa brevitarsis Nozaki & Maruyama sp. nov.

Figs 3 G, 17 A – L, 18 (Japanese name: Nise-yamato-hirata-ariyadori)

Material examined.

Holotype • 1 ♂; “ Nipppon: Honshû / Wakayama-ken / Minabegawa-mura / 17. VII. 1999 (banana t) / leg. Maruyama-M. ” (KUM).

Paratypes. Japan: Honshu; Wakayama-ken • 1 ♂; Kimitoge Pass, Hashimoto-shi; 6. VII. 2014; T. Ito leg. (OMNH) • 1 ♀; same locality; 9. VII. 2008; T. Ito leg. (OMNH) • 1 ex.; Tsuchibotoke-tôge, Iwade-shi; 10. V. 2019; I. Matoba leg. (OMNH) • 1 ♀; same data as holotype (KUM) • 2 ♂♂, 3 ♀♀; Nishihara (alt. 180 m) [33.781, 135.413], Hidakagawa-chô; 11. VI. 2023; TS. Nozaki leg. LFS (KUM) .

Diagnosis.

This species is distinguished from other species of the genus by the following combination of characteristics: pronotal postero-lateral angle around 90 degrees (Fig. 17 C); metatarsi shorter than half of metatibiae (Fig. 17 F, G); apical lobe of paramere short, broad, and almost straight, length about 1 / 4 of whole paramere, apex distinctly truncate (Fig. 17 K). This species is similar to H. japonica and H. prolongata in general appearance, but it can be distinguished from these two species by its very short metatarsi and truncate apex of the parameral apical lobe.

Description.

Body (Fig. 3 G) small, broad; dorsal surface mostly moderately polished.

Head large; color brown; eyes small. Antennae (Fig. 17 A, B) short relative length of each antennal segment from first to 11 th, 2.48: 1.96: 1.39: 1.22: 1.04: 1.09: 1.00: 1.15: 1.15: 1.37: 3.26.

Thorax. Pronotum (Fig. 17 C) subrectangular, transverse (PW / PL, 1.56–1.66), widest near middle, postero-lateral angle around 90 degrees, posterior margin slightly sinuate, reddish brown, surface finely covered with setae and punctures, gently polished and slightly reticulated. Elytra (Fig. 17 C, D) slightly widened posteriad, widest at middle, then narrowed roundly, posterior margins deeply notched near lateral corners, reddish brown, surface finely covered with setae and punctures; gently polished and finely reticulated. Hind wings developed. Mesoventral process (Fig. 17 E) very narrow, with weak medial carina, forming Y-shaped, apex pointed, reaching posterior 1 / 3 of mesocoxal cavities. Metaventral process slightly produced.

Abdomen elongate, narrowed posteriad; surface covered with short setae and each posterior margin with long stout setae; finely reticulated.

Male: Metatarsi (Fig. 17 F) as long as 1 / 3 of hind tibia. 8 th sternite (Fig. 17 H) produced roundly at postero-medial margin; median lobe of aedeagus (Fig. 17 J) slender, length about 0.61 mm, apical lobe narrow, slightly curved ventrally, apex gently pointed in lateral view, apical valves elongate and mitten-shaped, dorsal arms long and sharpened apically, basal part of copulatory piece small. Paramere (Fig. 17 K) length about 0.73 mm; apical lobe of paramere short and broad, length about 1 / 4 of whole paramere, almost straight, apex distinctly truncate; four setae, b located subapically, c irregularly located more dorsally; velum elongate and narrow.

Female: Metatarsi (Fig. 17 G) slightly shorter than half of metatibia. 8 th sternite (Fig. 17 I) slightly rounded posterior margin; spermatheca (Fig. 17 L) apex of basal part slightly swollen, base largely hooklike.

Measurements (in mm) and ratios.

Body parts (N = 8): BL ≈ 2.35–2.87; AL, 0.79–0.88; HW, 0.53–0.59; PL, 0.57–0.64; PW, 0.9–0.99; EL, 0.46–0.52; EW, 0.91–1.04; HTL, 0.6–0.74; PW / PL, 1.56–1.66; AL / PL, 1.35–1.46; HTL / PL, 1.04–1.22.

Differences between sexes: HTL (male, N = 4), 0.69–0.74; HTL (female, N = 4), 0.6–0.66; HTL / PL (male, N = 4), 1.09–1.22; HTL / PL (female, N = 4), 1.04–1.09.

Distribution.

Japan (Kii peninsula, Honshu) (Fig. 18).

Symbiotic hosts.

Lasius fuliginosus species group: Lasius spathepus .

Bionomics.

Homoeusa brevitarsis sp. nov. was collected from foraging trails of host ants on the forest floor from May to July. No individual was collected using FIT. Their behavior with the host ants is unknown.

Remarks.

Although several hundred Homoeusa specimens collected from colonies of the Lasius fuliginosus species group were examined in this study, this new species is only known from the Kii Peninsula, suggesting a restricted distribution.

Etymology.

The specific name is derived from the Latin adjective, which means “ short footed ” and refers to the short tarsi of this new species.