Vietnagone, new genus

Type species. Vietnagone silvatica, new species.

Etymology. The generic name is a combination of two words: “Vietna”, from part of the name of the country of origin of its type species, while the end part refers to the generic name Erigone; the gender is feminine.

Diagnosis. The genus contains erigonines with a total length of 1.50–1.78, which are characterised by the following combination of somatic and genital characters:

1) carapace unmodified in both sexes, cephalic pits absent (see Figs. 1, 2);

2) chelicerae strong, a mastidion absent;

3) chaetotaxy formula: 2.2.1.1; all metatarsi with a trichobothrium; TmI 0.39–0.44;

4) palpal tibia relatively large, modified (see Figs. 7–9);

5) median membrane strongly reduced (see Fig. 7);

6) distal suprategular apophysis moderately developed (see Fig. 10);

7) radix small, convector present;

8) embolus whip-shaped, looped (see Fig. 11);

9) abdomen with a pattern in both sexes (see Figs. 1–3);

10)epigyne without a distinct cavity (see Figs. 3, 12).

Taxonomic remarks. Based on the male palp conformation and somatic characters (see items 2–4, 7 from the list above), the new genus is similar to Gongylidioides Oi, 1960, but distinguished by the unusual shape of the palpal tibia (Figs. 7–9 cf. Figs. 1G, 2H, 3H, 5G, 6G in Tu & Li, 2006), the peculiar structure of the convector, which in Vietnagone, new genus is divided into two parts (vs. unipartite in Gongylidioides, see Tu & Li, 2006, Song & Li, 2010), as well as by the structure of the epigyne, namely the fused lateral walls covering the epigynal cavity (vs. spaced lateral walls in Gongylidioides, Fig. 12 cf. Figs. 1H, 2I, 3I, 4C, 6H in Tu & Li, 2006).

Species included. The genus contains two species: Vietnagone silvatica, new species (the type species) and V. rugulosa (Song & Li, 2010), new combination, ex Gongylidium Menge, 1868.

Distribution. Southeastern Tibet (Song & Li, 2010) and northern Vietnam.