A survey of East Palaearctic Gnaphosidae (Araneae). 2. Two new Gnaphosa Latreille, 1804 species from Western Mongolia

Abstract Two new species: Gnaphosa khovdensis sp. n. (♂) and G. esyunini sp. n. (♂♀) are described from Khovd Aimag of Mongolia. Descriptions, figures, diagnosis and map of the records are provided. The new species are assigned to a monophyletic group together with the recently described G. ustyuzhanini Fomichev et al., 2013.


Introduction
Gnaphosa Latreille, 1804 is the third largest genus of ground spiders with 141 species (Platnick 2014) and is one of the best-studied species rich genera of Holarctic spiders. The genus occurs from south China (Song et al. 2004) to the high Arctic reaching 71°34'N in Greenland (Marusik et al. 2006) and 72°15'N in Asia (Marusik et al. 1993).
The genus has been well studied in wide scale revisions of the Nearctic (Platnick and Shadab 1975), European (Grimm 1985), Asian (Ovtsharenko et al. 1992) and Chinese (Song et al. 2004) species.
While studying material collected in Western Mongolia and particularly in Khovd Aimag we recognized two unknown species related to each other and to the recently described G. ustyuzhanini Fomichev et al., 2013. Goals of this paper are to provide detailed descriptions of the new species and to discuss their relationships.

Gnaphosa khovdensis
Female unknown. Distribution. Known from the type locality only (Fig 19). Etymology. The species is named after our colleague Sergei L. Esyunin from Perm University (Russia), noun.
Diagnosis. Males of the new species differ from all congeners by the large embolic spine directed prolaterally. Females of G. esyunini sp. n. substantially differ from other species by the very wide fovea and the shape and angle of the lateral pockets.
Epigyne as in Figs 13-16; fovea very wide, especially in posterior half, 2.2 times wider than scape; scape oval, wider than long, with large hood; lateral pockets long, at an angle of about 45° to epigastral fold; glandular part of receptacles stretched horizontally.

Gnaphosa ustyuzhanini Fomichev, Marusik & Omelko, 2013 Figs 17-18
Gnaphosa ustyuzhanini Fomichev et al. 2013: 153, f. 1-10 (♂). Comments. The type series of this species was collected at the same place where the type locality of G. khovdensis sp. n. is located. The newly examined specimen has a more prominent embolic spine than in the holotype and paratype males.

Discussion
Although Gnaphosa can be considered as a well studied genus and contains almost 150 species it was never subdivided into monophyletic groups on a global scale. Asian species have been assigned into 10 informal species groups (Ovtsharenko et al. 1992). This informal grouping was made simply to assist identification of the over 60 species known in the former USSR and Asia.
It seems that the three Mongolian species treated here, all from Khovd Aimag, form a monophyletic group, which shares the same characters such as the short tibial apophysis (not longer than tibia); raised base of embolus; base of embolus with spine in anterior part; filamentous and rounded embolus with serrated prolateral edge; and simple median apophysis with claw-like tip. Members of other Asian species groups may have any mentioned character but never all together. For example some species in the lugubris-group have a triangle or claw-like spine on the base of embolus, but never an anterior spine and they have a modified median apophysis with an enlarged base. Members of the muscorum-group have a filamentous curved embolus and short tibial apophysis, but with the base of the embolus low, never having a spine but rather a kind of spur or serrated keel. Species of the rufula-group have a spine or claw-like embolic tooth or nearly a spine, but have a long tibial apophysis and straight embolus, and/or modified median apophysis.