Pardosa pyrenaica, Kronestedt, 2007

Kronestedt, Torbjoern, 2007, A new species of wolf spider from the Pyrenees, with remarks on other species in the Pardosa pullata-group (Araneae, Lycosidae), Zootaxa 1650, pp. 25-40 : 25

Pardosa pyrenaica sp. n

Pardosa femoralis Simon : Villaronga 1983: 806, figs 1-4

Villaronga 1986: 286, fig. 2 (misidentification).

Type material.

Male holotype from Andorra, Canillo, Bordes d’Envalira, 42°34′00″N, 1°41′00″E, 2010m a.s.l., grassy slope, 4 May 2006, T. Kronestedt (NHRS).

Other material examined

ANDORRA: Canillo: Bordes d’Envalira, 42°34′00″N, 1°41′00″E, 2010m a.s.l., grassy slope, 4 May 2006, 1♂, 1♀, T. Kronestedt (NHRS, collection series of holotype) ; same locality, 29-30 April 2007, 20♂, 10♀ (many caught as subadults and reared to adults), T. Kronestedt & K. Sindemark Kronestedt (NHRS). . FRANCE. Pyrénées-Orientales: Col de Puymorens, 42°33′00″N, 1°49′00″E, grassy vegetation at creek, 30 April 2007, 3♂, 3♀, T. Kronestedt (MNHN) . SPAIN. Catalunya: Espot, 42°34′30″N, 1°05′00″E, 1500m a.s.l., 29 July 1975, 1♂, 2♀, J. Barrientos (NHRS) .

Etymology

The specific epithet refers to the occurrence of the species in the Pyrenees mountain range.

Diagnosis

Males and females can be distinguished from other species in the pullata -group, except P. pullata , by comparatively short legs I and II as well as the occurrence of scopulate hairs on Ti (distally only), Mt and Ta of legs I and II. Males can be distinguished from those of P. pullata by the shape of the distally tapering embolus. Females can be distinguished from those of P. pullata by the course of the receptacula and usually by proportions in the shape of the epigyne (some overlap due to morphological variation).

Description

Male (based on holotype from Bordes d’Envalira, Andorra)

Total length 4.7. Carapace length 2.60, width 1.80.

Prosoma. Dorsum dusky brown with radiating black striae, furnished with recumbent dark pubescence. Median band and continuous lateral bands yellowish-brown. Ocular area black. Clypeus yellowish-brown. Chelicerae brownish with longitudinal darker stripes. Sternum dusky brown with narrow lighter, longitudinal median spot in anterior part.

Eyes. Width of row I 41 (slightly procurved as seen from in front), row II 64, row III 80; row II–III 61. Diameter of AME 9, ALE 8, PME 24, PLE 20. Distance between AME 6, between AME and ALE 2.

Opisthosoma. Dorsum dusky brown with brownish, sooty-bordered lanceolate stripe and indistinct pattern of symmetric sooty patches/bars. Venter brown with pubescence of recumbent light hairs and scattered thin dark hairs.

Legs. Yellowish-brown. Coxae dorsally dusky brown. Femora proximally darker. Remaining segments unicolorous. Legs I and II heavily furnished with scopulate hairs ventrally on Ti (distalmost part only), Mt and Ta [Figs 1-4, quite similar to the condition in P. pullata , but different from the dense, relatively long pubescence in P. femoralis (Figs 6-7)]. Ti I and II without retrolateral spines. Leg length IV>III>I>II (Table 1).

Pedipalp (Fig. 9). Pt 0.50, Ti 0.38, Cy 0.95. Pedipalp brownish with dark hairs. Distal part of cymbium yellowish. Main branch of tegular apophysis relatively narrow and evenly curved retrolaterally [Figs 9, 13; cf. P. pullata (Figs 11, 14) and P. femoralis (Fig. 15)]. Conductor apically with rounded rim [Fig. 19; cf. P. pullata (Fig. 20) with apical portion of conductor truncated]. Conductor and terminal apophysis connected as in P. pullata , lacking the “fissure” present in P. femoralis (Fig. 18, arrow). Terminal apophysis forming a sclerotised, slightly curved tooth, more or less concealed by conductor in ventral view [Figs 16, 19, 22; cf. P. pullata (Figs 17, 20, 23) and P. femoralis (Figs 18, 21, 24)]. Embolus long and curved, gradually tapering to tip [Figs 10, 19; cf. P. pullata : embolus apically widening and forked (Figs 12, 20), and P. femoralis : embolus even longer, curved, gradually tapering to tip (Fig. 21)].

Female (based on specimen from Bordes d’Envalira, Andorra)

Total length 5.50. Carapace 2.70 long, 1.95 wide.

Prosoma and opisthosoma. Colouration similar to male.

Legs. Light brown (similar to male). Fe with slightly darker pseudoannulation dorsally. Ti and Mt sometimes with traces of slightly darker annulation. Ti I and II without retrolateral spines. Legs I and II with scopulate hairs distributed as in male although less developed (and less visible). Leg length IV>III>I>II (Table 1).

Epigyne (Figs 25-27, 31, 33). Anterior epigyneal pockets widely separated, long and narrow; anterior margin of epigyneal grooves curved slightly backwards (Figs 27; arrow in Fig. 31) or evenly curved (Fig. 26). Epigyne reminding of that in P. pullata , although usually smaller and without the marked curvature in the anterior margin of the epigyneal grooves that is often present in the latter species (Fig. 28; arrow in Fig. 34). Receptacula long, proximal and distal parts in the same plane (Fig. 32, cf. P. pullata with distal part situated somewhat deeper: Fig. 35). Due to considerable morphological variation, there is some overlap in the shape of the epigyne between the two species (cf. Figs 27 and 30).

Habitat. Pardosa pyrenaica sp. n. seems to thrive in open grasslands at higher altitudes in the Pyrenees. The type locality in Andorra is situated on a slope with a cover of last year’s compressed grass that displays a more or less moist ground surface in spring (Fig. 46). The spiders moved quickly on the grass and escaped by “diving” into the grass cover.

Leg length in species of the Pardosa pullata -group

The proportions of the lengths of different leg segments in relation to the total length of the respective leg (expressed in % of the entire leg) are rather similar in the different species of the group as exemplified here by legs I and IV (Table 2). Therefore the use of the tibial length alone, for example, appears to be justified as an expression of the length of leg I or IV (Table 3).

Comparison of leg lengths versus body size (as expressed by carapace length) in species of the Pardosa pullata -group revealed a distinct difference between P. pyrenaica sp. n. and P. pullata on the one hand and the rest of the species on the other. The former two species have relatively short legs compared to the other members of the group (cf. TotIL/CL and TotIVL/CL in Table 2). The restricted leg elongation is notably developed in legs I and II. Consequently, the ratio tibia I length versus tibia IV length, notably in the males, gives a smaller value in P. pyrenaica sp. n. and P. pullata than in the other species of the pullata -group (cf. TiIL/TiIVL in Table 3), and a corresponding difference is found when comparing tibia II with tibia IV (pers. obs.).

Precopulatory behaviour in Pardosa pyrenaica sp. n. and P. pullata

Observations on male-female encounters in P. pyrenaica sp. n. revealed elements of precopulatory behaviour quite similar to those displayed in P. pullata . In both species the male rapidly jumped onto the female in an effort to cling onto her. Either the male clasped the female with his legs (Fig. 43) or, when failing to do so, grabbed one of her legs between his chelicerae before trying to mount her (Figs 41, 45). The male may approach the female from any direction (Fig. 43). During the interplay, which appeared like a struggle (Figs 37-40, 44), the female may fall into some cataplectic state (Fig. 38). The male gradually moved into the position for copulation common for lycosids. If the female escaped, the male might walk away with short, exaggerated steps.

An additional behavioural element was observed in P. pyrenaica sp. n. When a male stood at some distance from a female he, following a previous contact with her, may have made some alternating waving movements with his pedipalps (Fig. 42). These movements gave the impression of being somewhat occasional.

Discussion

Pardosa pyrenaica sp. n. clearly belongs to the pullata -group of species due to the division of the tegular apophysis into two membranously connected sclerites ( Holm & Kronestedt 1970). P. pyrenaica sp. n. and P. pullata share somatic characteristics that are not found in other species of the group, such as comparatively short legs. Moreover, legs I and II in both species are furnished with numerous scopulate hairs ventrally on the tibiae (distally only), metatarsi and tarsi (cf. Figs 1-2).

Morphological modifications in the first pair of legs have evolved in a variety of wolf spiders. In a recent review, Framenau & Hebets (2007) distinguished three categories of modification, viz. elongation, swelling and exaggerated setation. These manifestations of sexual dimorphism are expressed in males and are often associated with sexual behavioural traits. The restricted leg elongation in P. pyrenaica sp. n. and P. pullata represents another morphological modification which, like the presence of numerous scopulate hairs, is expressed in both sexes of these two species.

Comparatively short legs as well as the distribution of scopulate hairs on legs I and II in P. pyrenaica sp. n. and P. pullata may be associated with the precopulatory behaviour in these species, i.e. they may facilitate the physical contact between the sexes.

The presence of scopulate hairs in the tarsi and metatarsi in other lycosid species has earlier been ascribed to provide an adhesive mechanism for prey capture ( Rovner 1978: Rabidosa spp.). In P. pyrenaica sp. n. and P. pullata , the abundance of such hairs may aid in keeping the sexes together while the male orientates himself to a position for copulation.

Precopulatory behaviour, notably courtship display, has been shown to include species specific elements in many lycosid species and is often crucial for distinguishing closely related or cryptic species (e.g., TöpferHofmann 2000 and references therein). Precopulatory behaviour in P. pullata was observed by Bristowe & Locket (1926), Hallander (1967), and Den Hollander et al. (1973) who stated that there is no significant visual courtship display in this species. Instead the male jumps onto the female or chases her and seizes one of her legs before clinging onto her, subsequently orientating himself to the usual position for copulation (Kronestedt 1979). Vlijm & Borsje (1970) distinguished some additional elements in the precopulatory behaviour in P. pullata , including ‘courting’ - "slow motions of pedipalps and legs, the tips of which describe an arch". Such an element was not observed in P. pullata from Sweden. Maybe it is equivalent to the additional element of alternating pedipalpal movements as observed in P. pyrenaica sp. n.

Another species in the P. pullata -group, P. riparia , is also devoid of a significant visual courtship display. Instead the male pursues the female before mounting her for copulation. In this species, however, there is no clasping or clinging by the male before mounting for copulation (Kronestedt 1979). Other species in the P. pullata -group have characteristic courtship displays involving stereotypic visual and seismic or vibratory elements ( Den Hollander et al. 1973; Kronestedt 1973, 1979).

Similar morphological traits (leg proportions, occurrence of scopulate hairs) and precopulatory behaviour of P. pyrenaica sp. n. and P. pullata provide no support to separate them as different species. An additional behavioural element, however, alternate waving of pedipalps in male P. pyrenaica sp. n., has not been observed in P. pullata . The latter does not seem to be a significant behavioural component and one might consider it vestigial. Among other species of the pullata group, alternating pedipalp waving in males is a significant visual element in the courtship of P. fulvipes (Kronestedt 1979) . In the latter, however, the male pedipalps are distinctly coloured (black), contrary to the condition in P. pyrenaica sp. n., in which the male pedipalps are less conspicuous.

While P. pullata has a wide Palearctic distribution, from western Europe to Siberia (eastwards to central Siberia: Mikhailov 1997), it remains to be seen whether P. pyrenaica sp. n. is a high altitude sibling confined to the Pyrenees or if it occurs under similar conditions elsewhere in Europe.