Oia probosciella, Tanasevitch, 2022

Tanasevitch, Andrei V., 2022, Two new species and six new records of linyphiid spiders from Vietnam (Araneae: Linyphiidae), Raffles Bulletin of Zoology 70, pp. 305-311 : 306-307

Oia probosciella , new species

( Figs. 1–5 , 6–11 )

Type material. Holotype, male: northern VIETNAM, Vinh Phuc Province, Vinh Yen District, Tam Dao , 900 m a.s.l., 27 April 2000, coll. A. V. Abramov ( ZMMU); 2 females, paratypes, collected together with the holotype ( ZMMU).

Etymology. The species epithet is a Latin noun referring to the proboscis-like shape of the outgrowth on the palpal tibia in the male.

Diagnosis. The new species can be assigned to Oia , as being very similar to other congeners, according to the same chaetotaxy (2.2.1.1) and trichobothriotaxy (I–III), by the same modification of the carapace in both sexes, by some genitalia characters, i.e., the modified palpal tibia carrying a long and thick seta, the same simple structure of the embolic division in the male, as well as by the conformation of the epigyne, which has the epigynal plate. The new species is diagnosed by the proboscis-like shape of the palpal tibia, by the peculiar structure of the embolic division in the male, as well as by the trapeziform epigynal plate in the female. Oia probosciella , new species, particularly closely resembles the Eastern Chinese O. breviprocessia Song & Li, 2010 , and the Himalayan Oia kathmandu Tanasevitch, 2019 . The male of O. probosciella is easily distinguished from any congener by the proboscis-like shape of the palpal tibia, and by the absence of a lateral apophysis on the palpal tibia. Besides that, the new species has no apical spear-shaped process on the distal suprategular apophysis as observed in O. kathmandu and, unlike O. breviprocessia , it has two welldefined radical apophyses in the embolic division. The female of O. probosciella , new species, differs from O. kathmandu and O. breviprocessia by the trapeziform epigynal plate.

Description. Male holotype. Total length 1.15. Carapace 0.55 long, 0.45 wide, prominent behind a very compact ocular area, as in Figs. 1–3 ; pale brown to brown, with a narrow grey margin. Sulci absent. Chelicerae 0.25 long, a mastidion absent. Legs pale brown. Leg I 1.49 long (0.45 + 0.18 + 0.35 + 0.26 + 0.25), IV 1.44 long (0.45 + 0.15 + 0.33 + 0.28 + 0.23). Chaetotaxy 2.2.1.1, spines 0.5–1 times as long as diameter of corresponding leg segment. Metatarsi I–III each with a trichobothrium. TmI 0.31. Palp very small ( Figs. 6–10 ): Patella elongated, broadened distally. Tibia with a long, slightly curved outgrowth on prolateral side, ending with two small denticles, and a thick seta dorsally. Paracymbium very small, hook-shaped. Distal suprategular apophysis weakly sclerotised, conical distally. Embolic division: radix large and broad, distally with two sclerotised folds resembling slender radical apophyses; embolus short, a slender tube. Abdomen 0.63 long, 0.48 wide, dark grey ( Figs. 1, 2 ).

Female paratype. Total length 1.28. Carapace less prominent behind ocular area than in male ( Fig. 4 ); pale brown, 0.55 long, 0.48 wide. Chelicerae 0.28 long, a mastidion absent. Legs pale brown. Leg I 1.39 long (0.38 + 0.18 + 0.33 + 0.25 + 00.25), IV 1.34 long (0.43 + 0.15 + 0.30 + 0.23 + 0.23). Chaetotaxy 2.2.1.1, spines 0.5–1 times as long as diameter of corresponding leg segment. Metatarsi I–III each with a trichobothrium. TmI 0.44. Abdomen 0.80 long, 0.60 wide, grey ( Figs. 4, 5 ). Epigyne ( Figs. 5 , 11 ): Epigynal plate trapeziform, twice as high as base. Receptacles subspherical or bean-shaped.

Distribution. Known only from the type locality in northern Vietnam.

Figures

Figs. 1–5. Habitus of Oia probosciella, new species, male holotype (1–3) and female paratype (4, 5). 1–3, male body, dorsal, lateral and frontal views, respectively; 4, 5, female body, dorsal and ventral views, respectively. Scale bar = 0.5 mm.

Figs. 6–11. Details of male palp structure of Oia probosciella, new species, male holotype (6–10) and epigyne of female paratype (11). 6, 7, right palpal tibia, retrolateral and prolateral viewers, respectively; 8, patella and palpal tibia, prolateral view; 9, distal suprategular apophysis, antero-retrolateral view; 10, distal suprategular apophysis and embolic division, ventro-prolateral view; 11, epigyne, ventral view. Scale bars = 0.05 mm.