Nasoonaria annam, 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 : 308-310

Nasoonaria annam , new species

( Figs. 12–17 , 18–23 )

Type material. Holotype, male, southern VIETNAM, Ba Ria-Vung Tau Province, Bing Chau-Phuoc Buu Nature Reserve , 10°32′N, 107°29′E, 50 m a.s.l., June 2007, coll. A. V. Abramov ( ZMMU); 1 male, 1 female paratypes, collected together with the holotype ( ZMMU).

Etymology. The specific epithet is a noun in apposition referring to Annam, the old name of the country of origin.

Diagnosis. The new species can be assigned to Nasoonaria , based on the chaetotaxy (2.2.1.1) and trichobothriotaxy (I– IV), the structure of the male palp, which has a hypertrophied distal suprategular apophysis, the presence of a convector, as well as the presence of a whip-shaped embolus. The epigyne in the female is also of the same conformation as in most congeners. The new species is diagnosed by the unmodified carapace, by the complex and peculiar shapes of both the distal suprategular apophysis and the embolic division in the male. The female is distinguished by the structure of the epigyne. The species seems to be especially similar to Nasoonaria sinensis Wunderlich & Song, 1995 . The male differs by the simple shape of the palpal tibia (vs. strongly modified in N. sinensis ), as well as by the non-segmented radix in the embolic division. The female differs from all congeners by the presence of a dark and well-sclerotised epigynal plate partly covering the epigynal cavity.

Description. To avoid causing damage to the holotype, the male paratype is described here in due detail. Some measurements of the holotype are given in brackets. Carapace and abdomen shapes, body and leg colouration of the holotype are the same as in the male paratype.

Male paratype. Total length 1.85 (holotype 2.00). Carapace 0.85 long, 0.68 wide, unmodified, as in Figs. 12, 13 , yellow to pale brown. Chelicerae 0.38 long, a mastidion absent. Legs yellow to pale brown. Leg I 3.26 long (0.85 + 0.23 + 0.85 + 0.78 + 0.55); IV 3.21 long (0.90 + 0.20 + 0.83 + 0.78 + 0.50). Chaetotaxy: 2.2.1.1. Length of spines 1.5–2 diameters of leg segment. All metatarsi with a trichobothrium. TmI 0.84 (0.77 in holotype). Palp ( Figs. 18–22 ): Tibia expanded anteriorly, with a deep notch retrolaterally. Paracymbium L-shaped, its distal part massive, slender when viewed from above, proximal part narrow, tapering and fang-shaped. Distal suprategular apophysis hypertrophied, long proximally, relatively narrow; abruptly widened distally, ending with a long thin process. Median membrane narrow at base, tongue-shaped. Embolic division with a complex radix and a slender, slightly curved convector. Embolus thin, long, whip-shaped. Abdomen 1.13 long, 0.70 wide, dorsal pattern as in Figs. 12, 13 .

Female paratype. Total length 2.23. Carapace 0.88 long, 0.70 wide, yellow to pale brown, unmodified, as in Fig. 13 . Chelicerae 0.40 long, a mastidion absent. Legs yellow to pale brown. Leg I 3.28 long (0.90 + 0.25 + 0.88 + 0.75 + 0.50); IV 3.32 long (0.93 + 0.23 + 0.88 + 0.80 + 0.48). All metatarsi with a trichobothrium. TmI 0.77. Abdomen 1.50 long, 1.03 wide, abdominal pattern as in Figs. 14, 15 . Epigyne ( Figs. 15–17 , 23 ): Epigynal plate well-sclerotised, dark, bean-shaped, partly covering the epigynal cavity. Seminal ducts slender, forming an unclosed arch.

Distribution. So far known only from the type locality in southern Vietnam.

Figures

Figs. 12–17. Habitus of Nasoonaria annam, new species, male paratype (12, 13) and female paratype (14–17). 12, 13, male body, dorsal and dorso-lateral views, respectively; 14, 15, female body, dorsal and ventral views, respectively; 16, 17, epigyne, ventral view, different aspects. Scale bar = 1.0 mm (Figs. 12–15); 0.1 mm (Figs. 16, 17).

Figs. 18–23. Details of male palp structure of Nasoonaria annam, new species, male paratype (18–22) and epigyne of female paratype (23). 18, 19, right palp, retrolateral and prolateral views, respectively; 20, palpal tibia and paracymbium, dorsal view; 21, distal suprategular apophysis, frontal view; 22, embolic division, ventro-prolateral view; 23, epigyne, ventral view. Scale bars = 0.1 mm.