Paralipsis triangulata Kim & Yoon 2026, sp. nov.

Paralipsis triangulata Kim & Yoon sp. nov. Figs 2 A – O, 3 A – H Suppl. materials 1 –7 Korean name. 삼각뿌리진디벌 (신칭). Diagnosis. The new species shares with P. rugosa Tomanović & Starý, 2019 having the rugose propodeum (Fig. 2 F, G) and scutellum (Fig. 2 E). However, it clearly differs in having F 1 length equal to F 2 (Fig. 2 C), pterostigma length / width ratio over than 2.5 (Fig. 2 K), vein 2-1 A of the forewing faintly pigmented and unsclerotized, the presence of a distinct triangular lamellate projection on the outer basal margin of the fore femur (Fig. 3 B), and the presence of a distinct blunt subapical process in lateral view of fore basitarsus (Fig. 2 N) in P. triangulata sp. nov. In contrast, P. rugosa having F 1 length longer than F 2, pterostigma length / width ratio less than 2.0, vein 2-1 A sclerotized, and lacks such a projection on the fore femur and fore basitarsus. Description. Female from South Korea. Length of body in lateral view 2.5 mm (Figs 2 A, 3 A). Length of antennae 1.8 mm (Fig. 2 B). Head. Width of head 1.3 × middle length in dorsal view; posterior of antenna socket depressed; head 1.1 × wider than mesosoma at tegulae, with sparse erected setae; eye 0.6 × as long as temple in dorsal view (Fig. 2 D, H). Eyes small and oval, sparsely setose. Face moderately pubescent; width 2.5–2.7 × as wide as height; tentorial index (tentorio-ocular line / intertentorial line) = 0.6–0.7; clypeus oval with four long setae; malar space 0.6–0.7 × as long as longitudinal eye diameter (Fig. 2 D). Antenna 16 – segmented; F 1 1.0 × as long as F 2; F 1 and F 2 1.7 × and 1.8 × as long as their middle width, respectively; 2.3 × and 2.1 × as long as their basal width, respectively; penultimate flagellomere 1.8 × as long as their middle width; F 1–3 without longitudinal placodes, start with F 4 (Fig. 2 B, C). Maxillary palp with two palpomeres, labial palp with one palpomere. Mesosoma. Pronotum without pronope and subpronope (Fig. 2 E); present pronotal sulcus, almost reach to mesopleuron (Fig. 2 L). Mesopleuron finely rugulose – reticulate, with dense shallow impressions throughout (Fig. 2 L). Mesoscutum surface slight rugose, smooth area on dorsal and lateral lobes in each side (total four area); without notauli, covered with numerous long setae (Fig. 2 E). Scutellum nearly circular, protuberant; bearing numerous long setae, without scutellar sulcus carina (Fig. 2 E). Propodeum with coarse subconcentric rugae; interspaces shallowly impressed and irregularly reticulate (Fig. 2 F, G). Forewing. Pterostigma (= Stigma) with colorless area in both anterior and posterior side; 2.5–3.1 × as long as wide. Vein R 1 (= metacarpus) absence. Vein 2-1 A present, not sclerotized. (Fig. 2 K). Leg. Legs sparsely semi erected setose. Fore femur 4.0–4.4 × as long as maximum width. Fore tibia 6.5–7.0 × as long as maximum width with one tibial spur (Fig. 2 N). Fore femur length equal to fore tibia. Fore tarsus 3.0–3.3 × as long as fore basitarsus (= 1 st tarsomere); fore basitarsus straight, with a distinct blunt subapical process in lateral view; with a single row of densely comb – shaped setae; second fourth segments of fore tarsomeres length equal to width, claws acute (Fig. 2 N). Middle femur 4.6–5.0 × as long as maximum width. Middle tibia 8.1 × as long as maximum width with two tibial spurs. Middle femur length 0.8 × as long as middle tibia. Middle tarsus 3.0–3.3 × as long as middle basitarsus. Hind femur 4.1 × as long as maximum width (Fig. 2 M). Hind tibia 8.0–8.1 × as long as maximum width. Hind femur 0.7 × as long as hind tibia. Hind tarsus 2.2 × as long as hind basitarsus (Fig. 2 M). Metasoma. Petiole with prominent spiracular tubercles, 1.6 × as long as maximum width at level of spiracles and 2.7 × as long as width at level of posterior spiracles (Fig. 2 I, J). Ovipositor sheath short, straight, and slight broad in apex, 1.5–1.9 × as long as maximum width; with long hairs (Fig. 2 O). Color. Antenna light brown. Head light brown and dark brown dorsally; face, clypeus and mouthparts light brown. Mesosoma light brown with brown; mesoscutum brown in dorsal and light brown in lateral view. Both anterior and posterior of pterostigma with colorless area in forewing. Metasoma light brown. Legs light brown with dark apices. Distribution. South Korea. Biology. Unknown root aphid on Miscanthus sp., associated with colonies of Lasius koreanus Seifert, 1992. The parasitized aphids formed black mummies attached to the root and basal subterranean parts of Miscanthus sp. Etymology. The specific name triangulata sp. nov. refers to the distinct triangular lamellate projection on the outer basal margin of the fore femur. Type material. Holotype: South Korea • ♀; Mt. Goheon, Daehyeon–ri, Sannae–myeon, Gyeongju–si, Gyeongsangbuk–do from Lasius (Lasius) koreanus. colony; 28. IV. 2025; leg. S. Yoon; Dried mounted; specimen code: YPC 003118. Paratypes: South Korea • 4 ♀; same collection data as holotype; • 2 ♀ slide mounted specimen except one specimen’s head (Ap 26009); GenBank (Ap 26009, YPC 003120): COI, PZ 412707; 28 SD 2, PZ 411506; COII, PZ 416387; Cytb, PZ 420655; NAD 1, PZ 420657; Wingless, PZ 447458; GenBank (Ap 26010, YPC 003121): COI, PZ 412708; 28 SD 2, PZ 411507; COII, PZ 416388; EF 1 – alpha, PZ 447456; NAD 1, PZ 420658; Wingless, PZ 447459; • 2 ♀ alcohol preserved; specimen code: YPC 003117, YPC 003119. Additional material examined. South Korea • 4 ♀; same collection location as holotype; 28. IV. 2024; • ♀ alcohol preserved; specimen code: YPC 2293; 25. IV. 2026; • ♀ alcohol preserved; specimen code: YPC 3475; • 2 ♀ alcohol preserved; specimen code: YPC 3476_1, YPC 3476_2; these specimens are not included in the type series. Biological notes. All specimens of Paralipsis triangulata sp. nov. were collected from unidentified root-aphid colonies on Miscanthus sp. (Fig. 1 A, B, C) attended by Lasius koreanus. Individuals were usually found living together with aphid-attending ants and moved freely within the colony, and no aggressive behavior by the ant workers was observed. Aphid mummies, presumed belonging to the host root aphid, were found on the roots and basal subterranean parts of Miscanthus sp. (Fig. 1 A, B). On 28 April 2025, one adult that had failed to emerge from a mummy was observed. The mummy was tough and difficult to tear apart, and the emergence hole was nearly circular with an irregularly torn margin (Fig. 3 H). Adults were periodically observed licking the fore tibial spur (= calcar) with their mouthparts and then repeatedly used it to clean the antennae. During the behavior, the wasp hooked the base of antennae with the fore tibial spur and pushed it distally, cleaning the antenna with the dense comb of setae on the basitarsus (= 1 st tarsomere) (Fig. 3 C, D, Suppl. material 1). In addition, when approached by ant workers, individuals frequently waved their antennae and made contact with the ants. Under laboratory conditions, a characteristic riding behavior was repeatedly observed. P. triangulata sp. nov. approached stationary workers and mounted the dorsal surface of the ant with the fore legs held flexed in a mantis-like posture, positioning its body between the legs of the ant worker. During riding (Fig. 3 E, Suppl. material 2), the fore legs grasped the petiole and fore coxa of the aphid-attending ant, while the middle tibia repeatedly moved in a sawing motion, scraping the surface of the aphid-attending ant’s gaster toward the parasitoid’s body. The ridden ant generally stopped moving and lowered its body posture, apparently accepting the behavior. This posture was similar to that observed when workers receive grooming from nestmates. Riding behavior lasted for up to six minutes when uninterrupted. After riding, parasitoids were occasionally observed rubbing the middle and forelegs against each other, although this behavior was not consistently observed in all individuals. After repeated riding events, aphid-attending ants were frequently observed grooming the body of P. triangulata sp. nov. (Fig. 3 F, Suppl. materials 3, 4). Trophallaxis between ants and Paralipsis was also commonly observed, especially after honey water was provided. Ant workers often opened their mandibles and appeared to wait for trophallaxis when encountering P. triangulata sp. nov. (Fig. 3 G, Suppl. materials 5, 6). Parasitoids actively solicited trophallaxis by rapidly tapping the mandibles of the aphid-attending ants with their antennae and fore legs. The wings of all collected individuals were damaged, and the wing margins were irregular and ragged. During laboratory observation, individuals were observed pulling the damaged wings posteriorly with the apical parts of the hind tibiae. The apical parts of the hind tibiae reached approximately the regions corresponding to the damaged wing margins (Suppl. material 7). However, neither ant-mediated wing removal nor direct self-removal of wing tissue by the parasitoids was observed. Therefore, the mechanism responsible for the wing damage could not be determined from the present observations. On 9 May 2026, an experiment was conducted to examine acceptance among different ant colonies. One adult Paralipsis was introduced into a different colony of Lasius koreanus, which contained one adult Paralipsis and was located approximately 300 m from the original collection site. After investigation, the ant workers surrounded the introduced individual and repeatedly bit and pulled its legs and antennae. Although the parasitoid repeatedly contacted workers with its antennae, riding behavior was not observed. After approximately three hours, the individual was found dead, with its antennae and legs severed. When a worker of Lasius koreanus from the same colony as the introduced Paralipsis was introduced together, they were also killed in the same manner. Remarks. Paralipsis triangulata sp. nov. possesses a distinct triangular lamellate projection on the outer basal margin of the fore femur. This str