The pholcid spiders from Sri Lanka: redescription of Pholcus ceylonicus and description of a new genus (Araneae: Pholcidae)

The pholcid spiders of Sri Lanka have never been revised in any detail. Most species previously known from the island are widespread synanthropics. However, recent collecting has revealed a rich native fauna, with new taxa at species and genus levels. In this paper we redescribe Pholcus ceylonicus O. Pickard‐Cambridge, 1869, present the first record of Modisimus culicinus (Simon, 1893) for Sri Lanka, and describe two new species of a new genus, Wanniyala agrabopath n. sp. and Wanniyala hakgala n. sp. Both new species appear to be restricted to relatively undisturbed forests, where they inhabit the leaf‐litter. Several new Sri Lankan species tentatively assigned to Belisana Thorell will be described in a forthcoming revision of that genus. These studies suggest that a rich pholcid fauna may await discovery in Sri Lanka.


Introduction
Sri Lanka, together with the Westerns Ghats of southern India, is considered one of the global biodiversity hotspots (Myers et al. 2000). However, the diversity of the invertebrate fauna has never been assessed. In this study we consider the pholcid spiders of Sri Lanka. Of the seven species previously recorded for the island, only two are native (Table I; Pholcus ceylonicus; P. fragillimus), the other five are widespread synanthropics (Artema atlanta, Crossopriza lyoni, Holocneminus multiguttatus, Micropholcus fauroti, Smeringopus pallidus). However, as in other groups of spiders and vertebrates (Pethiyagoda 1994;Meegaskumbura et al. 2002;Benjamin 2004), recent collecting has revealed a diverse native fauna, at the level of both genera and species. This paper is the first in a projected series to treat this material. It provides a detailed redescription of Pholcus ceylonicus, including the first SEM photos of this species, and descriptions of two species of a new genus. This new genus is presently known from Sri Lanka only. However, as the fauna of the island is closely related to that of the Western Ghats (Lehtinen 1980;Meegaskumbura et al. 2002;Benjamin 2004) we assume that further Wanniyala species may occur there.
Several new Sri Lankan species tentatively assigned to Belisana Thorell will be described in a forthcoming revision of that genus. Further species with uncertain generic affinities (similar to Leptopholcus Simon and Pehrforsskalia Deeleman-Reinhold and van Harten) are currently represented by females only and will be described as soon as males are available. The type material of Pholcus fragillimus has probably been destroyed in Stuttgart during the Second World War (see Benjamin 2001), and only one female is available to us that might belong to that species. This study suggests that a rich pholcid fauna may await discovery in Sri Lanka. Intensified collecting and study, coupled with measures to protect the remaining forest fragments, are obviously the most important next steps.

Taxonomy
Style of descriptions is as in Huber (2000). Measurements are in mm unless indicated otherwise. The material studied is deposited in the collections of the Muséum d'Histoire Naturelle, Genève (MHNG), Muséum National d'Histoire Naturelle, Paris (MNHN), Collection C. L. Deeleman-Reinhold, deposited in the National Museum of Natural History, Naturalis, Leiden (RMNH), and Museum of Zoology, Turku (MZT).

Types
Male lectotype and two female paralectotypes (designated by Brignoli 1972), without locality information except Sri Lanka, in Hope Department of Entomology, Oxford, not examined (see Brignoli 1972 for detailed information on the type material).

Diagnosis
Large eight-eyed pholcid, easily distinguished from all known congeners by the shapes of procursus, bulb, male palpal trochanter apophysis, and epigynum ( Figure 2b, e).
Female. In general similar to male. Tibia 1 in three females: 9.0, 9.9, 10.3. Epigynum small in relation to abdomen (Figure 1c), with black sclerotized rim and variably sclerotized scape (Figures 1d, 2e, 4d). Dorsal view as in Figure 2f. Anterior lateral spinnerets with one widened, one pointed, and several (about six) cylindrically shaped spigots each (the latter spigots appear all damaged in Figure 4e). Posterior median spinnerets with two spigots each (one broken in Figure 4f).

Distribution
Known from several localities in Sri Lanka (Figure 9).

Material examined
Sri Lanka: ''Istripura'' [no further data on label ;Brignoli 1972: Hanguranketa, (7u109N, 80u469E), 19 January 1970, V. Aellen, P. Strinati], 2", 2R, several juveniles (three vials), in   Brignoli (1972) considered it probable that the present species will have to be removed from Pholcus. In fact, the bulb does not show the characteristic sclerites (uncus and appendix) of many other Pholcus species including the type species, and the procursus is unusually small and simple. However, male chelicerae and female epigynum agree with the usual pattern, as do general body shape and size. Most importantly, however, no evidence is known to suggest an alternative placement. The species should be left in Pholcus until a revision of the genus provides evidence to the contrary.

Etymology
Named for the Wanniyala-Aetto or ''forest people'', an indigenous people of Sri Lanka, commonly known as Veddahs. They are the earliest inhabitants with any living descendants in Sri Lanka. They have lived in their forest environment as hunter-gatherers for the past 18,000 years, but are now endangered due to rapid development and destruction of the forest habitat.

Diagnosis
Small pholcids (body length about 2 mm) with six eyes, long legs, and globular abdomen, distinguished from other pholcines by the male genitalia [procursus with distinctive distal hinged sclerite (Figure 7a, b, e, f), ventral transparent projection (t1 in Figure 7), prolateral proximal projection, and brush-like structure (t3 in Figure 7), bulb with tubular embolus and single sclerotized projection (Figure 6a

Description
See descriptions of the two species below.

Distribution
Known only from Sri Lanka (Figure 9). The genus might also occur in India, but the pholcid fauna of India has barely been studied.

Composition and relationships
The genus includes two named species (newly described below) as well as one unnamed species from Inginiyagala (7u139N, 81u329E), Badulla District (one male), and from Rattota (7u319N, 80u419E), Matale District (one male) (3634-35 in MZT). The latter species is not described because the female remains unknown. Wanniyala is clearly a representative of pholcines sensu Huber (2000). Within this subfamily, relationships remain largely obscure. This is mainly due to the fact that the large genus Pholcus and some potential relatives have never been revised.

Etymology
The specific name is a noun in apposition, taken from the type locality.

Diagnosis
Closely related to W. hakgala; easily distinguished by shape of dorsal sclerite on procursus (ds in Figure 7b), by epigynum without pointed projection (cf. Figure 5d and 5i); also by shorter clypeus projections, shorter cheliceral apophyses, and apparently by colour pattern (Figure 5a, b).
Male ( Figure 5a, b. Carapace ochre-yellow with wide blackish median band, without lateral dark margins, clypeus only slightly darkened; sternum pale ochre yellow. Legs pale ochre-yellow, dark rings on tibiae (subdistally). Opisthosoma grey with black pattern, ventrally without pattern. Ocular area slightly elevated, thoracic furrow very distinct frontally; distance PME-PME 70 mm; diameter PME 100 mm; distance PME-ALE 30 mm; AME absent. Clypeus with pair of short projections 35 mm long and indistinct median hump. Sternum wider than long (0.65/0.50). Chelicerae as in Figure 6c, e, with pair of long apophyses provided with two modified hairs on each tip (Figure 6d), tips 0.52 apart. Palps as in Figure 6a, b; trochanter with several short projections, femur with small proximo-dorsal apophysis, procursus very complex distally, apparently with two hinged processes, with three transparent processes (t1-3 in Figure 7a); bulb with distinctive hooked sclerite and membranous embolus (Figure 6a). Retrolateral trichobothrium of tibia 1 at 12%; most hairs on legs missing, but apparently without spines, without curved hairs, with several rows of vertical hairs on all metatarsi (clearly present in other male seen); tarsus 1 with .20 pseudosegments, only distally quite distinct.
Variation. Tibia 1 in male from Horton Plains: 3.2. This male differs also in colour pattern and is therefore assigned tentatively: lateral margins on carapace darkened, three pairs of black spots on sternum (cf. Figure 5e), with dark pattern on abdomen also ventrally, black rings also on femora (subdistally).
Female. In general similar to male, but clypeus unmodified and metatarsi without rows of vertical hairs; the female from Horton Plains has the same colour pattern as the male from this locality (see above). Tibia 1 in female from type locality: 2.85; female from Horton Plains: 2.55. Epigynum large but rather simple externally, without conical elevation (Figure 5c-e), apparently with pair of pockets 0.65 apart. Dorsal view as in Figure 7d.

Distribution
Known from two localities in Sri Lanka (Figure 9).

Etymology
The specific name is a noun in apposition, taken from the type locality.

Diagnosis
Closely related to W. agrabopath; easily distinguished by shape of dorsal sclerite on procursus (ds in Figure 7f), by epigynum with pointed projection (Figures 5i, 8d); also by longer clypeus projections, longer cheliceral apophyses, and apparently by colour pattern (Figure 5f, g).  Figure 5f, g. Carapace ochre-yellow with darker median and lateral bands, clypeus also darkened; sternum light brown. Legs pale ochre-yellow, slightly darker rings on femora (subdistally), patellae, and tibiae (subdistally). Opisthosoma grey with black pattern, ventrally also with dark pattern. Ocular area slightly elevated but distinct, thoracic furrow very shallow; distance PME-PME 140 mm; diameter PME 105 mm; distance PME-ALE 25 mm; AME absent. Clypeus with pair of short projections 90 mm long and distinct median hump. Sternum wider than long (0.75/0.60). Chelicerae very similar to W. agrabopath (cf. Figure 6c, e) with pair of long apophyses provided with two modified hairs on each tip (cf. Figure 6d), tips 0.88 apart. Palps in general very similar to W. agrabopath but significantly larger; trochanter and femur projections identical to W. agrabopath, procursus very similar to W. agrabopath, but with very different dorsal sclerite ( Figure 7f); bulb apparently identical to W. agrabopath (cf. Figure 6a). Retrolateral trichobothrium of tibia 1 at 13%; legs without spines, without curved hairs, with several rows of vertical hairs on all metatarsi; tarsus 1 with .20 pseudosegments, only distally quite distinct. Anterior lateral spinnerets with only two spigots each (Figure 8c). Male gonopore with four epiandrous spigots (Figure 8a).

Distribution
Known from three localities in Sri Lanka (Figure 9).