Chthonius carinthiacus Beier, 1951

Gardini, Giulio, 2021, The Italian species of the Chthonius ischnocheles group (Arachnida, Pseudoscorpiones, Chthoniidae), with reference to neighbouring countries, Zootaxa 4987 (1), pp. 1-131 : 22-26

Chthonius carinthiacus Beier, 1951

( Figs 60–76 , 404 )

Chthonius Rayi L. Koch, 1873: 48 (Razzes in der Ruine Hauenstein, in part).

Chthonius (Neochthonius) pygmaeus carinthiacus Beier, 1951: 165 , fig. 1c.

Chthonius cfr. ischnocheles ischnocheles: Callaini 1980a: 219 .

Chthonius (C.) baccettii Callaini, 1980b: 203 , figs Ia–f, II, IIIa–g, IVa–g (synonymized by Gardini 2004: 125).

Chthonius (Chthonius) carinthiacus: Gardini 2004: 125 (in part, see C. pygmaeus ); Christophoryová, Mock & Ľuptáčik 2011: 23, figs 1a–d; Novák 2012: 59, figs 2b, i; Novák et al. 2019: 129, figs 2a–c.

Type locality: Austria, Kärnten, Burgerboden bei Warmbad Villach (46°34’N, 13°50’E) .

Distribution. Czech Republic, Slovakia, Austria, Hungary, Romania, Switzerland, Italy (Eastern Alps).

Diagnosis (♂ ♀). An eyed epigean Chthonius that differs from other species of the ischnocheles group in the following combination of characters: anterior margin of carapace without preocular microsetae; posterior margin of carapace with 2 macrosetae, without lateral microsetae; chelicerae with 1 lateral microseta; palpal hand brown, usually darker than fingers, slightly conical in dorsal view; chela length 0.72–1.15 mm; movable chelal finger 0.46–0.73 mm; chela 4.4–5.75 times as long as deep; chelal fingers with reclined, pointed and widely spaced teeth; fixed and movable chelal fingers with 24–41 and 25–35 teeth respectively; fixed finger at level of est-it with 5–7 (♂) or 4–6 (♀) teeth occupying 0.1 mm, distance between successive apices 0.014 –0.023 (♂) or 0.018 –0.032 (♀) mm; ratio of pedipalpal femur/carapace 1.3–1.45.

Type material of Chthonius rayi examined. ITALY — Alto Adige : 6 ♂ 27 ♀ (paralectotypes of Chthonius Rayi L. Koch, 1873 , present designation), “Hauenstein” [Castelvecchio near Siusi allo Sciliar, com. Castelrotto, 1273 m a.s.l., 46°32’10”N, 11°34’06”E] “ Chthonius Rayi L. Koch ” “13.9.1.810–959” “ Chthonius rayi L. Koch / syntypes / M. Judson det. 1993” (together with 82 ♂ 58 ♀ of C. ischnocheles ) ( NHM 13.9.1.810–959) .

Type material of Chthonius pygmaeus carinthiacus examined. AUSTRIA — Kärnten: 1 ♀ (lectotype) 1 ♂ 1 ♀ (paralectotypes) ( V. Mahnert des., IV.1993), Warmbad Villach, Burgerboden, 520 m a.s.l., 14.IX.1949, H. Strouhal leg. ( NMW) .

Type material of Chthonius baccettii examined. ITALY — Alto Adige : 1 ♂ (holotype), 1 ♂ 1 ♀ (paratypes), “Andriano ( BZ), 18.9.76, [ R. Dallai leg.], castagneto fogliame e humus” ( MSNV) .

Other material examined. ITALY — Friuli: Pordenone Prov. — 1 ♀, Claut, Pinedo , 570 m a.s.l., 10.X.1993, F. Gasparo leg. , meadow. Friuli: Udine Prov. — 1 ♀, Bordano, 260 m a.s.l., 12. VI.1991, F. Gasparo leg.; 3 ♂, Cividale del Friuli, Castelmonte , 12.XII.1982, M. Seriani leg. ; 1 ♀ (together with 1 ♂ 1 ♀ 3 T of C. pygmaeus ), Paderno, Fiume Natisone, 90 m a.s.l., 23.IX.1983, M. Bodon leg. ; 1 ♂, Pontebba, Passo Pramollo , 1550 m a.s.l., 4.VII.1991, F. Gasparo leg. , pasture with Abies ; 1 ♂, San Pietro al Natisone, Monte Roba, 250 m a.s.l., 21. VI.2003, A. Pessina leg. ( MFNB); 1 ♀, Savogna, Monte Matajur, 1200 m a.s.l., 25. V.1986, S. Zoia leg.; 1 ♀, Trasaghis, Peonis, 180 m a.s.l., 29. VIII.1991, F. Gasparo leg., Ostrya carpinifolia wood; 1 ♂, Valbruna, 840 m a.s.l., 17. V.1991, F. Gasparo leg.; 1 ♀, Villa Santina, 400 m a.s.l., 30.IV.1991, F. Gasparo leg., under Carpinus ; 3 ♂, id., 29.IV.1994, F. Gasparo leg., pitfall trap on Carpinus wood; 1 ♀, id., 5.VII.1994, F. Gasparo leg., Carpinus wood. Veneto: Treviso Prov. — 1 ♀, Aviano, Cansiglio, 1200 m a.s.l., 6. VI.1974, A. Minelli leg.; 1 ♀ ( C. ischnocheles , det. M. Beier), id., 21.VII.1979, A. Minelli leg.; 3 ♂, Borso del Grappa , 1650 m a.s.l., 5. VIII.1986, E. Piva leg.; 1 ♂ 1 T (det. M. Beier), Vittorio Veneto, Fadalto , 12.IX.1972, A. Minelli leg. ; 1 ♀ ( C. tenuis , det. M. Beier), id., 17.IX.1972, A. Minelli leg.; 3 ♂ (det. M. Beier), id., 9.X.1972, A. Minelli leg. Veneto: Verona Prov. — 1 ♂, Brenzone, Monte Baldo, Val Trovai , 3. VIII.2009, E. Ruzzier leg.; 1 ♀, Dolcè, NW slope of Monte Pastello , 24.IX.1999, A. Zanetti leg. , beech wood; 2 ♀, San Zeno di Montagna, Val Trovai , 3. VIII.2009, G. Caoduro leg. Trentino: Trento Prov. — 2 ♀, Ala, Val Ronchi , 900 m a.s.l., 5.X.1989, S. Zoia leg. , beech wood; 1 T, Andalo , 1000 m a.s.l., 4.VII.1975, S. Zoia leg. ; 1 ♀, Concei, Monte Gaverdina , 1500 m a.s.l., 12.VII.1986, D. Vailati leg. ; 1 ♀, Fiera di Primiero, Passo Cereda , 1360 m a.s.l., 2.VII.1985, G. Gardini leg. , beech wood; 1 ♂, Imer, Rifugio Fonteghi, 1100 m a.s.l., 7. VIII.1991, F. Gasparo leg.

Description of adults (♂ ♀). Integument pigmented, carapace, tergites, chelicerae and pedipalps brown, palpal hand usually darker than fingers; weak hispid granulation on lateral surface of carapace, on cheliceral palm, on base of fixed chelal finger and on dorso–distal surface of chelal hand. Carapace ( Fig. 62 ) almost square shaped, moderately constricted posteriorly, 0.9–1.0 times longer than broad; anterior margin between median macrosetae strongly denticulate, with weakly prominent epistome in both sexes ( Figs 60–61 ); ocular area as in fig. 62, anterior bulging eyes with convex lens (diameter 0.050 –0.055 mm), posterior eyes with flat lens; distance from anterior eyes to anterior margin of carapace 0.030 –0.045 mm, distance from anterior to posterior eyes 0.05–0.08 mm, all eyes with a tapetum; chaetotaxy 4:6:4:2:2(18), anterior row rarely with 5 setae (♂ from Imer, Trento: fig. 62); length of anteromedian macrosetae 0.12–0.15 mm. Chaetotaxy of tergites 4:4:4:4:6:6:6:6:1T2T1:4:1T2T1:0. Chaetotaxy of sternites II–X: 7–10:(3)9–10(3):(2)7–9(2):8–9:6–8:6:6:6:2T1T2; genital opening of males flanked by 7–8 (rarely 5 to 10) setae on each side. Chelicerae ( Fig. 63 ) 1.9–2.15 (♂ ♀) times as long as broad, palm with 6 setae and 1 lateral microseta; fixed finger with 2 distal large teeth followed by 6–9 small teeth proximally reduced in size and few proximal microtubercles; movable finger with an isolated subapical tooth (di) at level with the spinneret, followed by a large tooth and 7–8 teeth proximally reduced in size; gs ratio 0.55–0.59; spinneret weakly prominent and rounded in both sexes ( Figs 63–64 ); rallum with 11 blades; serrulae interior and exterior with 14 and 17 blades respectively. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5, IV 6; coxa II with 4–11 (mainly 4–6) coxal spines, coxa III with 2–5 (mainly 3–4) coxal spines; intercoxal tubercle bisetose (with one seta in ♂ from Imer, Trento). Pedipalp: femur 4.7–5.2 (♂) or 4.7– 4.9 (♀) times as long as broad, femoral chaetotaxy 3:(5)6:2:5:1; chela ( Figs 67, 70 ) 5.1–5.75 (♂) or 4.4–5.0 (♀) times as long as deep; hand of chela 1.85–2.1 (♂) or 1.7–1.9 (♀) times as long as deep, slightly conical in dorsal view ( Figs 65–66 ); fixed chelal finger with 28–41 (♂) or 24–38 (♀) teeth inclined backwards: 4–7 small, contiguous and pointed distal teeth (the first distal one a little larger), proximally increasing in size, followed by large, sharp, reclined and widely spaced teeth, decreasing in size from trichobothrium est towards finger base; 4–9 proximal teeth low, rounded, gradually reduced in size ( Figs 67–70 ); all teeth with dental canal; fixed finger at level of est-it with 5–7 (♂) or 4–6 (♀) teeth occupying 0.1 mm, distance between successive apices 0.014 –0.023 (♂) or 0.018 –0.032 (♀) mm; tip of fixed chelal finger with apical sensilla af 1- 2, distal paraxial seta gradually curved and thin; movable chelal finger with 25–35 (♂ ♀) teeth, slightly scalene triangle-shaped, reclined and apically pointed proximally up to halfway between st-sb, rounded and increasingly reduced from sb towards finger base, reaching back near b (between sb and b they are mainly recognizable only by the presence of dental canal) ( Figs 67–70 ); movable finger at level of st-t with 5–7 (♂) or 4–6 (♀) teeth occupying 0.1 mm, distance between successive apices 0.014 –0.020 (♂) or 0.016 –0.028 (♀) mm; coupled sensilla pc at level of sb or just distad of sb; tip of movable chelal finger with apical sensilla am 1- 2; trichobothria as in figs 67, 70; ratio sb -st/sb -b = 1.5–2.2; ratio of movable finger/hand of chela 1.7–1.9 (♂) or 1.6–1.8 (♀); ratio of pedipalpal femur/movable finger 1.05–1.15 (♂ ♀); ratio of pedipalpal femur/carapace 1.3–1.45 (♂ ♀).

Measurements (in mm). Body length 1.4–1.6 (♂) or 1.6–2.15 (♀). Carapace 0.39–0.44 × 0.44–0.49 (0.395–0.44 anteriorly) (♂) or 0.45–0.60 × 0.52–0.66 (0.54–0.60 anteriorly) (♀). Chelicerae 0.38–0.42 × 0.185–0.21 (♂) or 0.41–0.615 × 0.22–0.29 (♀); movable finger length 0.19–0.22 (♂) or 0.22–0.31 (♀). Pedipalp: femur 0.50–0.575 × 0.10–0.115 (♂) or 0.56–0.835 × 0.12–0.17 (♀); chela 0.72–0.83 × 0.125–0.16 (♂) or 0.82–1.15 × 0.17–0.25 (♀); hand length 0.26–0.29 (♂) or 0.30–0.44 (♀); movable finger length 0.46–0.54 (♂) or 0.53–0.73 (♀).

Description of tritonymph. See Callaini (1980b).

Remarks. Chthonius pygmaeus carinthiacus was described by Beier (1951) from specimens of Carinthia ( Austria) for specimens with a larger body, less prominent epistome, darker chelal hand and a fixed chelal finger with larger, longer and more triangular teeth than the nominotypical subspecies.

Gardini (2004) upgraded Chthonius carinthiacus to full species status and proposed the synonymy of C. baccettii with C. carinthiacus .

Records of Chthonius carinthiacus [as C. (N.) pygmaeus carinthiacus ] for the specimens collected from cave Büs del Pian dei Calánch 307 Lo/BS were originally referred to as C. (N.) pygmaeus carinthiacus by Costantini (1976) but are regarded here as belonging to C. guglielmii . The same applies for records from the Lessini Mountains ( Lazzeroni 1969b). Citations of C. carinthiacus for Slovenia and Croatia ( Gardini 2004) actually refer to C. pygmaeus , and the record from Paderno, Fiume Natisone ( Gardini 2004), should be attributed in part to C. carinthiacus (1 ♀), and in part to C. pygmaeus (1 ♂ 1 ♀ 3 T).

Among the species of the Chthonius ischnocheles group, C. carinthiacus is most similar to C. pygmaeus , with which it shares the carapacal chaetotaxy (4:6:4:2:2) and the presence of 1 lateral microseta on the cheliceral palm. Chthonius carinthiacus differs from C. pygmaeus in the following characters: epistome broadly rounded, not prominent (prominent in C. pygmaeus ); chelal fingers with large, sharp, reclined and widely spaced teeth with sinuous distal side (with contiguous, slightly reclined teeth with convex distal side in C. pygmaeus ); fixed and movable chelal fingers (♂ ♀) at level of est -ist and st -t both with 4–7 teeth occupying 0.1 mm, distance between successive apices 0.014 –0.032 and 0.014 –0.028 mm respectively (with 6–11 and 6–10 teeth occupying 0.1 mm respectively; distance between successive apices 0.008 –0.019 and 0.009 –0.018 mm respectively, in C. pygmaeus ).

Chthonius carinthiacus can be related also to the hypogean C. gentianae , which occurs in the same geographical region. The two species share the same tooth pattern, the absence of preocular microsetae and have the posterior margin of carapace with 2 macrosetae, but without lateral microsetae. They differ in the lateral cheliceral microsetae (1 in C. carinthiacus , 2 in C. gentianae ) and for evident adaptive characters: anterior eyes with convex lens, posterior eyes with flat lens in C. carinthiacus (no eyes in C. gentianae ); male chela 5.1–5.75 times as long as deep (6.8 times in C. gentianae ); male chela length 0.72–0.83 mm (1.36 mm in C. gentianae ); male movable chelal finger length 0.46–0.54 mm (0.93 mm in C. gentianae ); male fixed chelal finger with 28–41 teeth (52 teeth in C. gentianae ).

The above description of Chthonius carinthiacus incorporates the one of C. baccettii ( Callaini 1980b) . Variability of chelal dentition in C. carinthiacus is represented in figs 71–76.

Figures

FIGURES 60–66. Chthonius carinthiacus Beier, 1951, Rifugio Fonteghi (Imer, Trento) (unless otherwise stated). 60, male, anterior margin of carapace; 61, female, Mt. Gaverdina (Concei, Trento), id.; 62, male, carapace; 63, male, right chelicera; 64, female, Mt. Gaverdina (Concei, Trento), movable finger of right chelicera; 65, male, right chelal hand, dorsal view; 66, female, Mt. Gaverdina (Concei, Trento), id.

FIGURES 67–70. Chthonius carinthiacus Beier, 1951, Rifugio Fonteghi (Imer, Trento) (unless otherwise stated). 67, male, right chela, antiaxial view; 68, male, detail of fingers at the distal half of right chela, antiaxial view; 69, male, detail of fingers at level of trichobothrium sb, antiaxial view; 70, female, Mt. Gaverdina (Concei, Trento), right chela, antiaxial view.

FIGURES 71–76. Chthonius carinthiacus Beier, 1951, detail of dentition at the chelal fingers tip, antiaxial view (setae and sensilla af1-2, am1-2 omitted). 71, male, Fadalto (Treviso); 72, male holotype of C. baccettii, Andriano (Bolzano); 73, female, Mt. Pastello (Dolcè, Verona); 74, male, Villa Santina (Udine); 75, female, Villa Santina (Udine); 76, female, Fiume Natisone near Paderno (Udine).

FIGURES 402–405. Distribution maps for the Italian species of the Chthonius ischnocheles group. 402, Chthonius agazzii Beier, 1966 and Chthonius comottii Inzaghi, 1987; 403, Chthonius alpicola Beier, 1951; 404, Chthonius carinthiacus Beier, 1951; 405, Chthonius guglielmii Callaini, 1986 and Chthonius ilvensis Beier, 1963.