Xerolycosa Dahl, 1908

Marusik, Yuri M., Kovblyuk, Mykola M. & Koponen, Seppo, 2011, A survey of the East Palaearctic Lycosidae (Araneae). 9. Genus Xerolycosa Dahl, 1908 (Evippinae), ZooKeys 119, pp. 11-27 : 13-14

Xerolycosa Dahl, 1908

Xerolycosa Dahl, 1908: 361. Type species: Lycosa nemoralis Westring, 1861.

Saitocosa Roewer, 1960: 889. Type species: Tarentula flavitibia Saito, 1934.

Diagnosis.

Members of this genus can be easily separated from otherEvippinae genera by the fewer number of ventral tibial spines on leg I (3pv & 2rv, or 2-2v), carapace lacking transverse depression (present in Evippa Simon, 1882) and lack of pseudo-articulation of tarsi (Fig. 13). Xerolycosa can be differentiated by the shape of their copulatory organs. Females have a short droplet-shaped septum (about as long as wide), while in Evippa the septum is long and has a well developed septal stem. The male palp in Xerolycosa has a shorter course of the seminal duct and a shorter embolus, which is only partly hidden by the tegulum.

Description.

Medium-sized (5.5-7.5) dark coloured or spotty lycosids. Carapace spotty or dark coloured with lighter median band and two lateral stripes. Cephalic region not elevated. Chelicerae with 3 promarginal and 2 retromarginal teeth. Inner side of chelicerae with a kind of stridulatory file (Fig. 12). Femora with 3 dorsal spines, tibia and metatarsus with 2 dorsal spines, sometimes poorly developed, tibia and metatarsi with four or five ventral spines (3pv-2rv or 2-2v). Tarsi without transverse furrow.

Male palp: cymbium with several apical spines; tegular apophysis shifted retrolaterally, with bill-like extension directed ventrally. Palea absent, embolus forming almost a circle, only partly hidden by tegulum. Epigyne: fovea (depression) absent, septum droplet-shaped, covered with hairs, almost as wide as high; stem short. Weakly sclerotized parts of epigyne are referred to here as windows (Wi).

Comments.

Saitocosa was synonymised with Xerolycosa by Yaginuma (1986: p. 169) through synonymisation of the type species Tarentula flavitibia Saito, 1934 with Xerolycosa nemoralis.

Dahl (1908) described Xerolycosa and placed only two species in this genus: Xerolycosa nemoralis and Xerolycosa miniata . No type species was selected. It is not clear who selected Xerolycosa nemoralis as the type species. The first clear indication we found was in Roewer's catalogue (Roewer 1954: p. 309). The same species was indicated as the generotype in Roewer's revision of Lycosidae ( Roewer 1959: p. 893) and in Bonnet's catalogue ( 1959: p. 4836).

In Platnick's catalogue ( 2011) five species are listed under Xerolycosa : Xerolycosa miniata (C.L. Koch, 1834), Xerolycosa nemoralis (Westring, 1861), Xerolycosa pelengena Roewer, 1960, Xerolycosa sansibarina Roewer, 1960 and Xerolycosa undulata Chen, Song et Kim, 1998. Roewer's species are known from Africa (Congo and Zanzibar). Judging from the figures, Xerolycosa pelengena is a member of Trochosini , due to its carapace pattern (two dark longitudinal stripes within the median band, just behind the PLE) and epigyne (anchor-shaped septum, and triangle-shaped hoods of the apical pocket) and seems to belong to Trochosa . Therefore, we propose the new combination: Trochosa pelengena (Roewer, 1960) comb. n. Xerolycosa sansibarina , known from the male sex only, has a carapace and abdominal pattern very different from Evippinae species, and the palp has a distinctly different conformation, typical for the Lycosinae (tegular apophysis stretching horizontally, tip of embolus visible and resting horizontally in a tegular depression). However, we refrain from suggesting a new combination because its generic affinities are currently unclear.

Because of the burrowing behaviour in Xerolycosa mongolica (Schenkel, 1963), believed to be absent in the other species, we first followed A.A. Zyuzin's (personal communication) opinion that it may belong to a separate genus. However, females of Xerolycosa nemoralis are known to excavate shallow depressions in soil ( Smola 2007). In addition to behaviour, Xerolycosa mongolica has widely spaced posterior median eyes (one diameter apart) in contrast to the type species, Xerolycosa nemoralis , and Xerolycosa miniata (less than one diameter apart). Study of the male palp and the leg spination revealed no differences between Xerolycosa mongolica and the other species.