Xysticus alpinus Kulczyński, 1887

Ballarin, Francesco, Pantini, Paolo & Gobbi, Mauro, 2018, Elevation to species level and redescription of Xysticus alpinus Kulczyński, 1887 stat. n. (Araneae, Thomisidae), Zootaxa 4500 (2), pp. 271-280 : 272-276

Xysticus alpinus Kulczyński, 1887 stat. n.

Figures 1–5 , 10–11 , 14–17

Xysticus lateralis alpinus Kulczyński, 1887: 257 , 302–304 (Dmf) [in World Spider Catalog up to version 19.5 it was erroneously stated that only the female was described].

Xysticus lanio alpinus (Kulczyński) . Roewer 1954: 903; Jantscher 2001: 175–179, figs 49a–f

Xysticus lanio C. L. Koch. Bonnet 1959: 4885 .

Material examined. AUSTRIA: Tirol: 1♀, Wolfendorn, 2300 m, leg. K. Schmölzer ( NMB 436Ib) ( Jantscher 2001 sub X. lanio alpinus ). GERMANY: Bayern: 1♂, Schönau am Königssee, Berchtesgaden National Park, "Wildpalfen" site with Carex firma , 47.498070N, 13.041180E, 2209 m, 4 August–14 September 2015 ( CTB). ITALY: Lombardia: 5♂♂, 6♀♀, Sondrio, Ortles-Cevedale Massif, Braulio valley, Rock Glacier Vedrettino, 46.501389N, 10.401389E (~ 15km west of X. lanio alpinus type locality), scree slope, 2555 m, pitfall traps, 19 August 2013; 3♂♂, 1♀, calcareous alpine grassland, 2460 m, 19 August 2013; 1♂, 4♀♀, 12 September 2013, all leg. I.A. Muzzolon ( MSNV); 1♂ calcareous alpine grassland, 2460 m, 22 August 2014; 3♀♀ 28 September 2014; 1♂, 3♀♀, 13 September 2014; 1♂ scree slope, 2555 m, 22 August 2014; 3♂♂, 1♀, 13 September 2014; 1♀, rock glacier, 2530 m, 22 August 2014; 1♂, 13 September 2014; all leg. G. Boffa, D. Tampucci ( MSNB). Trentino Alto Adige: 2♂♂, Bolzano, Antersasc, 9‒29 July 1995, leg. V. Zingerle ( NSB) ( Zingerle 1997 sub X. lanio ); 3♂♂, 2♀♀, Gsellwiesen (Sesto), 24 July–22 August 1997, leg. V. Zingerle ( NSB) ( Jantscher 2001 ♂♂ sub X. lanio lanio , ♀♀ sub X. lanio alpinus ; Zingerle 1999a sub X. lanio ); 2♂♂, 1♀, Bolzano, Passo Sella, 25 June–25 July 1997, 5♂♂, 25 July–21 August 1997, leg. V. Zingerle ( NSB) ( Zingerle 1999a sub X. lanio ); 2♂♂, 1♀, Bolzano, Weisshorn (Corno Bianco), 7 August–6 September 1998 ( NSB) ( Jantscher 2001, ♂♂ sub X. lanio , ♀♀ sub X. lanio alpinus ; Zingerle 2000a sub X. lanio ); 2♂♂, 1♀, Trento, Passo Rolle (Parco Naturale di Panaveggio), 28 July–27 August 1997, leg. V. Zingerle ( NSB) ( Zingerle 2000b sub X. lanio ). Veneto: 5♂♂, Belluno, Dolomites, Sorapiss Massif, Debris-covered glacier Sorapiss, 46.510833N, 12.211389E, ~ 130km East of X. lanio alpinus type locality), glacial moraine, 2220 m, pitfall traps, 5 July 2017; 16♂♂, 1♀, 27 July 2017; 2♀♀, 17 August 2017, leg. M. Gobbi ( MSNV); 3♂♂, Belluno, Passo Valparola, 15 July‒14 August 1998, leg. V. Zingerle ( NSB) ( Zingerle 2000a sub X. lanio ). SWITZERLAND: Bern: 1♀, Berner Oberland, Isenfluh, leg. N. Stöcklin-Müller ( NMB, 436c) ( Jantscher 2001 sub X. lanio alpinus ). Glarus: 1♂, Linthal, Obersand, 5–17 August 2008, leg. D. Gloor ( NMB 20659) ( Gloor 2009 sub X. lanio ). Graubünden: 1♂, Davos, Weissfluhjoch, 9 June–27 July 2003, leg. WSL Birmenstorf staff, Projekt RBA ( NMB 26180). Luzern: 1♂, Sörenberg, Schrattenfluh, ~ 2000 m, 28 August 2009 ( NMB). Schwyz: 1♀, Muothatal, Chaiserstock, 16 June 2010, leg. S. Brenneisen ( NMB 28634); 1♀, Val del Diavel, Natural Park, 2100 m ( NMB 436Ia) ( Schenkel 1923 sub X. lateralis var. alpinus ; Jantscher 2001 sub X. lanio alpinus ).

Comparative material examined. Xysticus lanio . GERMANY: Bayern: 6♂♂, 13♀♀, Neustadt an der Aisch-Bad Windsheim Dorngrund, Hutung, Gebüsch 11May ‒22 July 1997, leg. E. Bauchhenss ( NMB 22440). Rheinland-Pfalz: 1♂, near Mainz, between Mombach and Gonsenheim, NSG Grosser Sand, 14 June 1958, leg. R. Braun; 1♀, Gonsenheimer Wald, 27 June 1958, leg. R. Braun ( SMF). ITALY: Piemonte: 5♂, 2♀, Cuneo, Entracque, Gorge della Reina, sparse wood, grassland and rock-debris, 900 – 1200 m, 22 May 2010, leg. M. Isaia ( UNITO). Toscana: 1♂, 1♀, Firenze, Marradi, Mt. Bruno, 1089 m, 16 May 2003, leg. A. Usvelli ( MSNB). Puglia: 2♂♂, Foggia, Gargano, Nature Reserve Foresta Umbra, May 1950, leg. S. Ruffo ( MSNV). Sardegna: 3♀♀, Nuoro, Belvi, “su Enazzu”, hazel grove, 39.978004N, 9.184633E, 550 m, 16 June 2005, leg. I.S.E ( MSNB). SERBIA: Vojvodina: 3♂♂, Beoči, Pinus forest Fruska Gora, 12 June 2010, leg. G. Grbic ( NMB 21193). SWITZERLAND: Basel-Landschaft: 14♂♂, 25♀♀, Basel Umgebung, leg. E. Schenkel ( NMB 436a) ( Müller & Schenkel 1895; Jantscher 2001). Tessin: 1♂, Centovalli, Lionza, 22 May 1989, leg. A. Hänggi ( NMB 00436k) ( Hänggi 1992); 1♀, V. Maggia, Someo, gravel banks, 8 June 1989, leg. N. Patocchi ( NHMB 436i) ( Jantscher 2001). Wallis: 2♀♀, leg. M. Paul ( NMB 436d) ( Jantscher 2001); 1♀, 1♂, Dorénaz, Mt. Rosel, 15 May 1987, 20 June 1987, leg. R. Delarze ( NMB 20503, 20504) ( Delarze & Hänggi 1996). Graubünden: 1♀, Trinser Mühle, leg. E. Schenkel ( NMB 436h) ( Schenkel 1933 sub X. lateralis ; Jantscher 2001).

Xysticus desidiosus Simon. ITALY: Friuli Venezia Giulia: 2♂♂, Udine, Chiusaforte , Gruppo Canin-Sella di Grubio , 2100 m, 28 July–27 August 2001, pitfall trap, leg. A. Dall’Asta, G. Governatori ( MFSN) . Lombardia: 1♂, 1♀, Sondrio, Braulio valley, Rock Glacier Vedrettino , 46.505000N, 10.400000E, pitfall trap, calcareous alpine grassland, 2460 m, 19 August 2013 leg. I.A. Muzzolon ( MUSE) .

Diagnosis. This species is closely related to Xysticus lanio but slightly larger in size, with a darker and more uniform colouration and with conspicuously shorter, thicker spines covering the whole body ( Figs 1–2 vs. 6–7). Males of X. alpinus stat. n. can be easily distinguished from those of X. lanio by the shorter and slightly curved PTA, in contrast with the longer and straighter PTA of X. lanio ( Figs 3 , 14 vs. Figs 8 , 18 ). Females can be separated from those of X. lanio by the different shape and orientation of EP, oblong and parallel to each other in X. alpinus stat. n., more rounded and divergent in X. lanio . In addition, PM appears more sclerotised and clearly bordered by a continuous transverse fold in X. alpinus stat. n. ( Figs 5 , 10 , 16 vs. Figs 12 , 20 ). The comma-like shape of the CD is also diagnostic, with the final portion strongly bent inward in X. alpinus stat. n., in contrast with the almost straight ducts of X. lanio ( Figs 11 , 17 vs. 13, 21). Xysticus . alpinus stat. n. bears a superficial resemblance to the cohabiting alpine species X. desidiosus . However, males can be easily separated by the different shape of the PTA (thinner and straighter in X. alpinus stat. n., thicker and more hook-like in X. desidiosus ), and by the different position of MTA, protruding distally from the bulb (approx. 12 o’clock seeing the left palp ventrally) in X. alpinus , in contrast with the diagonally protruding MTA (approx. 2 o’clock) in X. desidiosus ( Figs 3 , 14 vs. fig. 29a in Jantscher 2001). Females are quickly distinguished by the general shape of the epigyne, and by the form of the EP, which is convex and large in X. alpinus stat. n., and concave, smaller, and limited only to the anterior half of the epigyne in X. desidiosus ( Figs 10 , 16 vs. fig. 29c and figs 30a, c, e in Jantscher 2001).

Redescription. Male. Total length: 4.84–5.92. Carapace: 2.52–2.95 long, 2.19–2.67 wide (based on 6 males from Vedrettino rock glacier).

Habitus as in Fig. 1 . Carapace dark brown with lighter eye region and longitudinal band, and a narrow white stripe along the margins. Chelicerae uniformly dark brown, toothless. Labium, gnathocoxae and sternum in the same colour of chelicerae. Dorsal side of the opisthosoma brown or grayish-brown, with a narrow white band around the lateral side and a barely visible pattern of lighter spots. Ventral side uniformly dark brown. Spinnerets brown. Carapace and opisthosoma covered with numerous strong, short hairs. Legs with two tarsal claws, femur and patella dark brown with a lighter dorsal stipe or mark, metatarsus and tarsus uniformly brown. Leg measurements as following (based on one male from Vedrettino rock glacier): I 10.34 (3.11, 1.26, 2.43, 2.39, 1.15), II 10.06 (3.03, 1.18, 2.35, 2.30, 1.20), III 7.02 (2.25, 0.88, 1.58, 1.43, 0.88), IV 7.35 (2.30, 0.92, 1.68, 1.55, 0.90).

Leg formula: I, II, IV, III. Leg spination:

Palp as in Figs 3–4 , 14–15 . Tibia with 2 apophyses: VTA rectangular with a squared tip, RTA short and blunt, ending with a short pointed tip. Two strongly sclerotised tegular apophyses: PTA short and sharply pointed, slightly distally curved, MTA massive, hook-like. EM long and narrow with inconspicuous tip.

Redescription. Female. Total length: 7.65–10.07. Carapace: 3.47–4.16 long, 3.40–3.86 wide (based on 6 females from Vedrettino rock glacier).

Habitus as in Fig. 2 . Carapace dark brown with lighter eye region and longitudinal band, sometimes two black marks present near the posterior border. Narrow white stripe along the margins. Chelicerae uniformly dark brown, toothless. Labium, gnathocoxae and sternum in the same colour. Opisthosoma uniformly greyish-brown, lacking a clear pattern with the exception of two narrow white stripes along the lateral sides. In few specimens, a wide, slightly lighter stripe may be present along the midline. Spinnerets brown. Carapace and opisthosoma covered with short, strong hairs. Legs with two tarsal claws, uniformly brown, dorsal side of femur and patella darker. Leg measurements as following (based on one female from Vedrettino rock glacier): I 12.59 (3.76, 1.81, 2.94, 2.78, 1.3), II 12.51 (3.96, 1.81, 2.98, 2.51, 1.25), III 8.95 (2.94, 1.39, 1.95, 1.60, 1.07), IV 9.61 (3.06, 1.34, 2.20, 1.90,

1.11). Leg formula: I, II, IV, III. Leg spination:

Epigyne and vulva as in Figs 5 , 10–11 , 16–17 . EP strongly sclerotised and convex, ovoid, longer than large, parallel to each other, distinctly protruding outside the epigynal plate. MS with longitudinal grooves. PM strongly sclerotised, clearly separate from the epigynal plate by a transverse fold. CD curved, comma-like, with the posterior part strongly bent inward.

Type locality. Italy, Alto-Adige / Südtirol , Stelvio , Trafoi and Solda valleys (“Dolina Trafojska: kolo Franzenshöhe, kolo lodowca Madatschferner, Ferdinandshöhe.·Dolina Suldenska” Kulczyński 1887: 257) .

Distribution. Austria, Germany, Italy, Switzerland. Endemic to the Central-Eastern Alps (sensu Marazzi, 2005). New material presented here confirms the presence of the species in the Bavarian and Swiss Alps. Reexamination of the female specimens from the Northern Alps as listed in Muster (2001, sub X. lanio ), under consideration of the present redescription, confirmed that this material also belongs to X. alpinus stat. n. (Muster pers. comm.).

Remarks on autoecology. Based on habitat descriptions by Tampucci et al. (2015, 2017), and our field observations, we consider X. alpinus stat. n. a ground-dwelling species restricted to open habitats in high mountains. According to literature and our results, the vertical distribution of this species extends above 2000 m a.s.l. ( Zingerle 1997, 1999a, b, 2000a, b, Jantscher 2001, Thaler & Knoflach 2004; Tampucci et al. 2017). Above the timberline, X. alpinus stat. n. inhabits a variety of habitat types, such as alpine grasslands (calcareous alpine grasslands with Carex firma , Sesleria caerulea and Dryas octopetala -dominated community), scree slopes (unstable slopes with a patch distribution of Papaver aurantiacum , Saxifraga aphylla , Pritzelago alpina and Moehringia ciliate , Fig. 22 ) and rock glaciers (exclusive coexistence of the plants Arabis caerulea and Saxifraga oppositifolia ) ( Tampucci et al. 2015). According to Tampucci et al. (2017) it occurred more frequently on scree slopes (57% of the sampled material), followed by alpine grasslands (28%) and rock glaciers (15%), so it may prefer rocky terrains. The specimens collected in this study were found on N-NW facing slopes with inclination of 0–35 degrees. The activity of X. alpinus stat. n. coincided with the snow-free period, from mid-July to mid- September. According to literature, X. alpinus stat. n. and X. desidiosus can coexist in the same habitat ( Zingerle 1999b, Tampucci et al. 2017). However, X. desidiosus appears to prefer alpine grasslands rather than scree slopes, where X. alpinus stat. n. is more abundant ( Tampucci et al. 2017).

Figures

FIGURE 22. Scree slope surrounding the Vedrettino rock glacier, habitat in which the largest population of Xysticus alpinus stat. n. was found (Photo by M. Gobbi).

FIGURES 1–9. Habitus and genitalia in comparison. 1–5 X. alpinus stat. n. from Vedrettino rock glacier (1 habitus of male, 2 habitus of female, 3 male palp ventral, 4 ditto retrolateral, 5 epigyne ventral); 6–9 X. lanio from Marradi (6 habitus of male, 7 habitus of female, 8 male palp ventral, 9 ditto retrolateral).

FIGURES 10–13. Female genitalia after maceration. 10–11 X. alpinus stat. n. from Vedrettino rock glacier (10 epigyne ventral, 11 vulva dorsal); 12–13 X. lanio from Marradi (12 epigyne ventral, 13 vulva dorsal).

FIGURES 14–21. Genitalia in comparison. 14–17 X. alpinus stat. n. from Vedrettino rock glacier (14 male palp ventral, 15 ditto retrolateral, 16 epigyne ventral, 17 vulva dorsal). 18–21 X. lanio from Marradi (18 male palp ventral, 18 ditto retrolateral, 20 epigyne ventral, 21 vulva dorsal).