Ischyropsalis lithoclasica, Schönhofer, Axel L. & Martens, Jochen, 2010

Schönhofer, Axel L. & Martens, Jochen, 2010, On the identity of Ischyropsalis dentipalpis Canestrini, 1872 and description of Ischyropsalis lithoclasica sp. n. (Opiliones: Ischyropsalididae), Zootaxa 2613, pp. 1-14 : 9-12

Ischyropsalis lithoclasica sp. n.

Figs 2–4 , 11–21 , 29–32, 39

Ischyropsalis sp. aff. strasseri Roewer, 1950: Hadži 1954: 180 –183; Martens 1969a: 249, 252; Martens 1978: 200. I. strandi Kratochvíl, 1936 : Martens 1969a: 249 –252 (partim).

I. dentipalpis Canestrini, 1872 : Martens 1978: 49 –50, 188–189, 197–200, 206, 212, 219, 221 (partim).

Holotype: ɗ, ITALY, Lombardia, Prov. Bergamo, Valle Valzurio, Oltressenda Alta, Valley of Stalle del Möschel, “sorgenti di aria fredda” (meaning “spring of cold air”, a place now modified to store groceries), 1200 m, N: 45.945839° E: 10.009737°, R. Pisoni, M. Valle leg. by pitfall traps 18.08.– 09.09.1985 ( MSNB).

Paratypes (only adult specimens): Same data as for holotype, 9Ψ 1juv. ( MSNB); 3ɗ 6Ψ, R. Pisoni, M. Valle leg. by pitfall traps 1986 ( MSNB); 1ɗ 6Ψ 1juv., R. Pisoni, M. Valle leg. by pitfall traps 18.08.1985 ( MSNB); 2ɗ 1Ψ, M. Valle leg. by pitfall traps 1987–1988 ( MSNB); Oltressenda Alta, Valle Scura, 2200 m, N: 45.979663° E: 10.020870°, 1ɗ A. Andreani, P. Quirci, M. Valle leg. 13.07.1988 ( MSNB); 1ɗ M. Panololfi, P. Quirci, M. Valle leg. 27.09.1988 ( MSNB); picnic area W Stalle del Möschel, 1198 m, N: 45.93810° E: 10.00446°, 2ɗ 1Ψ 1juv, in cavities of large, mossy rocks in coniferous forest, A. Schönhofer leg. by hand 18.09.2009, ( Figs 1–4 , CAS 429); Premolo, Baita Camplano, 1800 m, N: 45.921134° E: 9.962669°, 1Ψ, Menabò, M. Valle leg. 24.07.1983, ( MTSN); doline a sud di Baita Camplano, pitfall traps, 1850 m, N: 45.92° E: 9.82°, 1juv., Museo Bergamo leg. by pitfall traps 29.09.2004 – 21.06.2005 ( MSNB); Roncobello, Sotto il Faggio, Buco del Castello (1309 Lo/Bg), 1340 m (not 700 m as given in Martens 1978 and Brignoli 1972), N: 45.95° E: 9.77°, 1ɗ 3Ψ, Bini leg. Dec. 1970 (CJM 1490); dito, 1Ψ, Nov. 1969 (CJM 1487); dito, 1ɗ, 25.07.1970 (CJM 1489); dito, 1Ψ 1juv., Apr. 1970 (CJM 1491); dito, 2juv., Nov. 1969 (CJM 1492); dito, 1ɗ 1Ψ, Dec. 1969 (CJM 1493); dito, 1juv., Dec. 1970 (CJM 1494); dito, 2juv., Dez. 1970 (CJM 1495); dito, 5juv. Dec. 1970 (CJM 1488); dito, 1ɗ, G. Comotti leg. 12.09.1982 ( MTSN); Corno Branchino and Lago Branchino, 1600–1794 m, N: 45.94931° E: 9.80257°, alpine meadow, under stones, 1juv., P. Pantini, A. Schönhofer leg. by hand 17.09.2009 ( CAS 409); Sant’Omobono Terme, Nala di Cà Maquela (1135 Lo/BG), 670 m, N: 45.80° E: 9.52°, 7juv., G. Comotti, A. Baldan leg. 0 4.03.1990 ( MSNB); Schilpario, Conca Baione, 2000 m, N: 46.021692° E: 10.249133°, 1ɗ, C. Ravazzi, M. Valle leg. 17.07.1986 ( MSNB); Vilminore di Scalve, Miniera Passo Manina, 1600 m, N: 46.01° E: 10.03°, 1ɗ 1Ψ, A. Baldan, G. Comotti leg. 19.08.1990 ( MSNB); Val Seriana, Boario de Grono, Büs di Tacoi (1007 Lo/BG), 1550 m, N: 45.96° E: 9.96°, 4Ψ, Bini leg. 29.06.1970 (CJM 1496); 1Ψ, Regalin leg. 17.10.1982, (chelicerae missing, MTSN); 1Ψ, E. Boesi leg. 29.06.1928 (CJH; Hadži 1954, I. aff. strasseri; Martens 1969a, I. strandi ); Ardesio, Cacciamali, Bora de l'Or, cave 1, 1225 m N: 45.94°, E: 9.91° (1225 Lo/BG), 5ɗ, G. Comotti leg. 26.06.1983 (chelicerae missing, MTSN); Valgoglio, Valsanguigno, stony gravel near lake under Pizzo Salina, 2150 m, N: 45.984477°, E: 9.854446°, 1ɗ, M. Massaro, W. Zucchelli leg., by pitfall traps 13.09– 30.10.2009 ( MSNB).

Diagnosis (see I. dentipalpis for an overall characterisation): Males are discernible by wedge-shaped distad-pointing apophyses on pedipalpal patella ( Figs 12, 14 ), by larger distal apophyses on basal cheliceral article with extended bristle areas ( Figs 11, 13 ) and by their genital morphology ( Figs 15–21 ). Females are discernible by the presence of a small spine in distal fifth of basal cheliceral article, which is much smaller than the large dorsal spines (Fig. 31; in few specimens absent, Fig. 32) and slender bristles of medium length on the opisthosomal tergites.

I. lithoclasica sp. n. is endemic to the Alps of Bergamo and the only Ischyropsalis species present in this area. Ischyropsalis ravasinii is very similar to I. lithoclasica sp. n. in featuring similar pedipalpal and cheliceral apophyses. However, genital morphology is clearly different and I. lithoclasica sp. n. is about 20% smaller in every respect. Chelicerae tend to be less slender and spines are more pronounced than in I. ravasinii . Both species are allopatric. Their distribution areas are separated by the alpine mountain massifs between Lake Iseo and Lake Garda, an area apparently uninhabited by Ischyropsalis .

Etymology: The name refers to the fact that this species inhabits cavities in clastic rocks at the type locality ( Fig. 1 ). The name, an adjective, is derived from the Greek “lithos” and “klastos” meaning broken stones.

FIGURES 29–38. Right chelicera. 29–30, 33–35: ď; 31–32, 36–38: Ψ. 29–32: Ischyropsalis lithoclasica sp. n., Italy, Prov. Bergamo; 29, 31: paratypes, Buco del Castello (CJM 1490; see also figs 320, 321 in Martens 1978); 30: holotype, Stalle Möschel (MSNB); 32: paratype, Bus di Tacoi (CJM 1496; see also fig. 322 in Martens 1978); 33–38: Ischyropsalis dentipalpis ; 33: Italy, Torino, Ceres (CJM 5930); 34: Switzerland, Ticino, Frasco (CJM 1480; see also fig. 383 in Martens 1978); 35: neotype, Italy, Aosta Valley (CJM 5918); 36: Switzerland, Sonogno (CJM 1481; see also fig. 384 in Martens 1978); 37: holotype of I. helvetica , Switzerland, Ticino (SMF RI/1282; see also fig. 385 in Martens 1978); 38: Switzerland, Rätikon, Sulzfluh (MHNG; see also fig. 386 in Martens 1978). All lateral view, scale bar (for all) 1 mm. Arrows indicate diagnostic characters mentioned in the text.

Description: Measurements: ɗ (n=9), Ψ (in parentheses, n=8). Body length: 4.08–5.52 (5.68–7.28); leg II: 25.3–32.8 (25.6–33.5), femur 5.60–7.44 (5.68–7.28), patella 1.35–1.68 (1.44–1.68), tibia 4.24–5.60 (4.56– 5.52), metatarsus 6.80–9.20 (7.04–9.52), tarsus 5.44–8.96 (6.80–8.24); basal article of chelicera 4.08–4.64 (3.84–4.64).

Penis morphology ( Figs 15–21 ): Truncus penis slightly belly-like and widened dorsally, from about midsection to glans parallel-sided, truncus close to glans, not bulged dorsally (lateral view, Figs 15, 18 ) but rather a straight prolongation of the remainder of the truncus ( Figs 17, 20–21 ). Glans variable in length, gradually narrowing into stylus ( Figs 15–16, 18–19 ), sclerite of glans narrow, ending in two broad and short lobes basally ( Figs 16, 19 ), median keel missing, bristle cover dense, the two bristle areas diverging towards distal part of glans ( Figs 16, 19 ), stylus remarkably long.

Chelicerae ( Figs 11, 13 , 29–32): ɗ basal article with irregular dorsal row of 6–8 spines of different size, in most specimens the distal one being much smaller than the largest dorsal spines, ventro-medially with 6–7, ventro-laterally with 9–11 spines; basal article dorso-distally with large bulging apophysis ending at article border, thereby not protruding over article border and not markedly pronounced, less regularly rounded than in I. dentipalpis ; area of bristles and secretory glands large, marked by lighter reddish colour, in dorsal view reaching dorsal side of apophysis, in lateral view covering most of dorso-distal part of apophyis ( Figs 11, 13 ); Ψ like in ɗ but without apophysis and bristle area.

Pedipalps ( Figs 12, 14 ): ɗ with small, wedge-shaped ventral apophysis at distal end of patella, pointed distally, thereby fitting on the tibia; apophysis missing in Ψ.

Legs: Robust, of medium length, dark brown, metatarsus and tarsus of lighter colour, base of femora whitish to yellowish.

Prosoma: Cephalothorax flat, moderately ascending from thoracic tergite II; with few fine granules, matt; thoracic tergite II with 9–13 spines of different sizes, medial ones being the largest, plump conical in shape; ocularium weakly developed, eyes widely separated, with small lenses.

Opistosoma: Scutal area finely spotted, with transversal rows of small tubercles carrying slender bristles of medium length; ɗ usually with scutum parvum, rarely with scutum intermedium (area 5 isolated, area partly separated, Figs 3–4 ), Ψ with scutum laminatum ( Fig. 2 ).

Variability: There seems to be no extraordinary variation despite the general differences in Ischyropsalis species, e. g. spination is more developed in larger specimens, (see Martens 1969a: 160–165). The glans penis may be quite variable, stout or more slender ( Figs 15–16, 18–19 ). This is also obvious in I. dentipalpis ( Figs 22–23, 25–26 ).

Distribution ( Fig. 39 ): Endemic to montane and alpine areas of the central Alps of the Bergamo area (Prov. Bergamo). The distribution area known so far is a narrow belt of only 60 km length and 15 km maximum width. The westernmost record is close to Lecco (Sant’Omobono) and the easternmost at the border to Val Camonica (Schilpario). Localities are concentrated in the area of Monte Arera (Roncobello, Oltre il Colle) and Monte Presolana (Oltressenda Alta, Vilminore) but this is probably only due to intense collecting activity in this area.

Ecology: While Martens (1978, sub I. dentipalpis ) stated that I. lithoclasica sp. n. is a troglobiont, the many specimens in pitfall traps at the type locality, as well as finds in small rock cavities in coniferous forest ( Fig. 1 ) and under stones in alpine meadows at even higher altitudes contradict his interpretation. It is a troglophilous species favouring cave habitats for their cool and moist microclimate, as does I. dentipalpis . The type locality meets these requirements quite nicely, being an interstitial habitat where cold air emanates from thick layers of clastic gravel. There I. lithoclasica sp. n. can be found in quite large numbers close to the surface. With increasing altitude (from about 1600 m upwards) the species is probably less bound to underground habitats and there are more epigeic records. The known vertical distribution spans from 670 m (cave Nala di Cà Maquela) to 2200 m (Valle Scura) but is likely to extend further up. One of us ( AS) found at 1200 m adults resting during the day on vertical rock faces in deep cavities and once, at night, specimens wandering on rock faces in close vicinity to these cavities ( Fig. 1 , Stalle del Möschel).

Conservation: Although I. lithoclasica sp. n. appears frequently in suitable habitats, which are numerous throughout its area, it is nevertheless a narrowly endemic species and therefore it requires particular attention. Considering the presence of many other endemic Opiliones taxa in the Alps of the Bergamo area, e.g. Holoscotolemon franzinii Tedeschi & Sciaky, 1994 , Mitostoma orobicum ( Caporiacco, 1949) , Mitostoma anophthalmum ( Fage, 1946) and Siro valleorum Chemini, 1990 , narrow endemism seems to be a common phenomenon in this region. This suggests a glacial “massifs de refuge” and outlines an area of unique biodiversity even within the small order Opiliones ; hence the region deserves conservation priority.

Figures

FIGURE 39. Localities of Ischyropsalis lithoclasica sp. n. (filled triangles) and I. dentipalpis (filled circles). Arrows point to locus typicus of I. dentipalpis (d) and of I. lithoclasica sp. n. (l).

FIGURES 1 – 4. Habitat and habitus of Ischyropsalis lithoclasica sp. n. 1: natural habitat in Italy, Prov. Bergamo, picnic area near Stalle Möschel and locus typicus “ sorgente di aria fredda ” where CAS 429 specimens (Figs 2 – 4) were collected in cavities; 2: Ψ; 3 – 4: ď.

FIGURES 5 – 14. Cheliceral and pedipalpal apophyses of ď. 5 – 10: Ischyropsalis dentipalpis; 5 – 6: Italy, Torino, Ceres (CJM 5930); 7 – 8: Switzerland, Ticino, Frasco (CJM 1480; see also figs 383 and 388 in Martens 1978); 9 – 10: neotype, Italy, Aosta Valley (CJM 5918). 11 – 14: Ischyropsalis lithoclasica sp. n., Italy, Prov. Bergamo; 11 – 12: Buco del Castello (CJM 1490; compare Fig. 11 with fig. 320 in Martens 1978); 13 – 14: holotype, Stalle Möschel (MSNB). 5, 7, 9, 11, 13: distal end of basal article and basal part of second article of right chelicera, medial view; 6, 8, 10, 12, 14: patella and parts of femur and tibia of right pedipalp, lateral view. Scale bar (for all) 1 mm. Arrows indicate diagnostic characters mentioned in the text.

FIGURES 15 – 28. Penes. 15 – 21: Ischyropsalis lithoclasica sp. n., Italy, Prov. Bergamo; 15 – 17: paratype, Buco del Castello (CJM 1490; see also figs 317, 323 in Martens 1978); 18 – 21: holotype, Stalle Möschel (MSNB). 22 – 28: Ischyropsalis dentipalpis, Italy; 22 – 24: Torino, Ceres (CJM 5930 CJM 5930; see also figs 382, 387 in Martens 1978); 25 – 28: neotype, Aosta Valley (CJM 5918). 15 – 16, 18 – 19, 22 – 23, 25 – 26: distal part of penis with glans and stylus, scale bar 0.5 mm; 17, 20 – 21, 24, 27 – 28: total penis, scale bar 1 mm; 15, 18, 21 – 22, 25, 28: lateral view; 16 – 17, 19 – 20, 23 – 24, 26 – 27: ventral view. Arrows indicate diagnostic characters mentioned in the text.