Philodromus histrio (LATREILLE, 1819)

Szita, É., Logunov, D. & O, P., 2008, A Review Of The Histrio Group Of The Spider Genus Philodromus Walckenaer, 1826 (Araneae, Philodromidae) Of The Eastern Palaearctic Region, Acta Zoologica Academiae Scientiarum Hungaricae 54 (1), pp. 23-73 : 25-27

The histrio species group

This species group is basically coextensive with the genus Rhysodromus

SCHICK, 1965 (the type species: Thomisus histrio LATREILLE, 1819 ). SCHICK (1965: 38, table 4) listed 9 morphological characters separating Rhysodromus from Philodromus (s. str.) and Ebo . By some of them (e.g. PME closer to PLE than to ALE, AME subeqaul to ALE), Rhysodromus seems to be closer to Ebo . Nevertheless, we agree with DONDALE and REDNER (1975: 371) that there is no single character distinguishing the histrio group from other groups of the genus. Thus, we follow the latter authors and consider the histrio group within Philodromus . The group can be diagnosed by a number of characters ( SCHICK 1965, DONDALE & REDNER 1975, 1976): the stout and straight embolus that terminates at the tip of the tegulum, a maximum of 2 pairs of ventral basitarsal spines (of which the second is situated at middle of segment or more basad), PME closer to PLE than to ALE, and the dense scopula (especially in females). We don’t know if either of the aforementioned characters is apomorphic or plesimorphic, as no phylogenetic analysis of the entire genus Philodromus , as well as any other philodromid genus, has been performed to date. This task is outside the scope of the current regional review.

Originally ( DONDALE & REDNER 1975), the histrio group comprised four species: P. alascensis , P. fallax , P. histrio and P. mysticus . A substantial recent improvement in the state of knowledge of Palaearctic Philodromus allows us to include at least 16 species in this group, of which 13 (five are new to science) are treated in the present paper. Most of them are clearly related to P. histrio , P. alascensis , P. fallax or P. pictus . One of the studied species, P. xinjiangensis , stands on itself within the group. Its male have the poorly marked embolus (Fig. 36), whereas the female’s epigyne resembles that of Thanatus ( Figs 45–46 ). Another species, P. pictus , possesses neither straight nor stout embolus. We have provisionally placed both these species in the histrio group and their proper assingment needs to be reconsidered in the future.

We have failed to trace and re-examine the type series of Philodromus cinerascens PICKARD-CAMBRIDGE, 1885 from Yarkand, which is not available in the HECO (checked by DL) and The Natural History Museum, London (pers. comm. by J. BECCALONI). This species, as PICKARD-CAMBRIDGE stated himself (1885: 74), was very close to P. fallax . So, it might be one of the species studied here, but on the basis of the original desription alone we cannot be sure. None of other PICKARD-CAMBRIDGE’ s Philodromus described from Yarkand (see PICKARD- CAMBRIDGE 1885) belongs to the histrio group (most of them are from the pulchellus group; types are availaible in the HECO and have been re-examined by DL).

Two more species are absent from the material examined here. One, P. leucomarginatus PAIK, 1979 was described from Korea after a single male ( PAIK 1979) and later also recorded from China (Inner Monglia, Shanxi and Shandong) ( TANG et al. 2004). Reasoning from the latest account by TANG et al. (2004: figs 3, A-C), who also described the female of P. leucomarginatus , it is safe to conclude that this species is a true member of the histrio group. The second species, P. hui YANG et MAO, 2002 was recently described from Yunnan Province of China ( YANG & MAO 2002) and is close to P. pictus (see below).

It is very likely that Philodromus pelagonus ŠILHAVÝ, 1944 described from Macedonia is a member of the histrio group as well. Reasoning from the original illustrations alone ( ŠILHAVÝ 1944: figs 6–7), it has been impossible to assign this name to any of the new species examined in our study.

Figures

Figs 39–46. Female genitalia of Philodromus spp. 39–40 = P. alascensis – 39 = epigyne, 40 = spermathecae. 41–42 = P. tuvinensis – 41 = epigyne, 42 = spermathecae. 43–44 = P. mysticus – 43 = epigyne, 44 = spermathecae.45–46 = P. xinjiangensis – 45 = epigyne,46 = spermathecae.Scale bar = 0.1 mm. Specimens:P.alascensis: Magadan Region, the upper reaches of Kolyma; P. tuvinensis: the paratype; P. mysticus: Chita Region, Sokhondo State Reserve; P. xinjiangensis: Uzbekistan,