Chthonius agazzii Beier, 1966

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 : 6-11

Chthonius agazzii Beier, 1966

( Figs 1–25 , 402 )

Chthonius (C.) agazzii Beier, 1966: 175 , fig. 1 (in part: ♀ only).

Chthonius (s. str.) ischnocheles ischnocheles: Lazzeroni 1969b: 390 (in part: see C. densedentatus and C. ischnocheles ). Chthonius (s. str.) malatestai Callaini, 1980a: 220 , figs 1a–c, 2a–d (n. syn.).

Chthonius (s. str.) agazzii: Callaini 1980a: 226 ; Gardini 1991: 172.

Chthonius (C.) jugorum: Minelli & Negrisolo 1993: 65 .

Type locality: Italy, Veneto, Treviso Province , Pederobba, La Bislonga 1001 V / TV (45°52’48”N, 11°57’41”E) .

Distribution. Italy (Friuli, Veneto and Trentino).

Diagnosis (♂ ♀). A microphthalmic epigean or hypogean Chthonius that differs from other species of the ischnocheles group in the following combination of characters: anterior margin of carapace with 1 (rarely 2) preocular microseta; posterior margin of carapace with 2 macrosetae, without lateral microsetae; chelicerae with 1 (rarely 2) lateral microseta; chela length 0.56–1.08 mm; movable chelal finger length 0.39–0.74 mm; chelal fingers with reclined, pointed, widely spaced teeth; movable chelal finger with coupled sensilla pc lodged on a noticeable tubercle.

Type material of Chthonius malatestai examined. ITALY — Veneto: Treviso Prov. — 1 ♂ (holotype), “Cansiglio [Fregona], 12.XI.1976, MG, [Mount] Pizzoc, faggeta” ( MSNV) .

Other material examined. ITALY — Friuli: Pordenone Prov. — 1 ♂, Aviano, Cansiglio , Col Piova , 21. VI.1973, R. Poggi leg. , beech wood; 4 ♂ 1 ♀, Aviano, near Madonna del Monte , 340 m a.s.l., 17.IV.1995, G. Governatori leg. ; 3 ♂, Aviano, Piancavallo, 1980–1990, M. Seriani leg., beech wood; 2 ♂, id., 15.XI.1981, M. Seriani leg.; 5 ♂ 4 ♀, id., 1250 m a.s.l., 3.VII.1983, M. Seriani leg.; 1 ♂, id., 1500 m a.s.l., 15. V.1994, G. Governatori leg., beech wood; 2 ♂, Barcis, Lago di Barcis , 409 m a.s.l., 7.X.1979, M.G. Paoletti leg. ; 1 ♀, Barcis, N slope of Montelonga , 800 m a.s.l., 11.IX.2006, G. Governatori leg. , beech wood; 1 ♀, Budoia, San Tomè di Dardago , 450 m a.s.l., 19.X.1993, F. Gasparo leg. , mixed wood; 1 ♂, Claut, Alta Val Cellina, Pian de Cea , 930 m a.s.l., 30. V.2002, A. Dall’Asta leg. , pitfall trap in beech wood; 2 ♂, Claut, near Stalle Parentonia , 750 m a.s.l., 22. VI.1996, G. Governatori leg. ; 1 ♂ 1 ♀, Claut, Val Settimana, between Stalle Parigina and Stalla Pustrin , 650 m a.s.l., 3. V.2002, A. Dall’Asta leg. , sieved in beech wood; 4 ♂, Clauzetto, Gerchia , 540 m a.s.l., 29.IX.1990, F. Gasparo leg. ; 3 ♂, Tramonti di Sotto, Bosco Selvaz, 21. VI.1987, L. Dreon leg. ; 4 ♂, Tramonti di Sotto, near Campone , 2.X.1985, S. Zoia leg. Friuli: Udine Prov. — 1 ♂ 2 ♀, Amaro, 350 m a.s.l., 8. V.1991, F. Gasparo leg. , wet meadows; 4 ♂ 5 ♀, Bordano, 260 m a.s.l., 12. VI.1991, F. Gasparo leg., pitfall traps; 1 ♂ 2 ♀, Forgaria nel Friuli, Monte Prat , 750 m a.s.l., 22.VII.1991, F. Gasparo leg. ; 1 ♀, Raveo , 430 m a.s.l., 21. VIII.1991, F. Gasparo leg. ; 1 ♂, near Tolmezzo , 23.VII.1978, S. Vit leg. ; 2 ♀, Venzone, Val Verzonassa, Rio Bruschie near Casera Frassin , 630 m a.s.l., 29. V.2008, L. Dorigo leg. , beech wood ( MFNB); 2 ♂ 1 ♀, Villa Santina, 400 m a.s.l., 29.IV.1994, F. Gasparo leg. , Carpinus wood; 1 ♂, id., 5.VII.1994, F. Gasparo leg., Carpinus wood. Trentino: Trento Prov. — 5 ♀, Vallarsa, Passo di Pian delle Fugazze , 1140 m a.s.l., 2.VII.2013, D. Bianco leg. , digging. Veneto: Belluno Prov. — 1 ♂, Belluno, N slope of Monte Faverghera , 1520 m a.s.l., 5.XI.2000, G. Peretto & E. Piva leg. ; 1 ♀, id., 20. V.2001, E. Piva leg.; 1 ♂ 1 ♀, Mel, Praderadego , 750 m a.s.l., 2.XI.1990, L. Latella & S. Zoia leg. ; 1 ♂, Pedavena, Le Vette Feltrine, 870 m a.s.l., 18. VI.1994, E. Piva leg., digging in canyon; 1 ♀, Schievenin , 350 m a.s.l., 29.III.1978, I. Löbl leg. ; 1 ♂, Sovramonte, Grotta Faller 3189 V /BL, 25.IV.2010, D. Bianco & G. Martini leg. Veneto: Treviso Prov. — 5 ♂ ( C. jugorum , det. M. Beier), Vittorio Veneto, Fadalto , X.1992, A. Minelli leg. ; 1 ♂ 1 ♀, id., Sella di Fadalto , 500 m a.s.l., 3. VIII.1991, F. Gasparo leg. ; 3 ♂ 2 ♀, Fregona, near Pian del Cansiglio , 1000 m a.s.l., 4.X.1985, S. Zoia leg. , beech wood; 1 ♂ 2 ♀, Mansuè, Basalghelle , 10.VII.1980, M.G. Paoletti leg. ; 3 ♂ 6 ♀, Milies , 30.III.1978, I. Löbl leg. ; 1 ♂, San Pietro di Feletto, Bus dei Tedeschi 1818 V / TV, 100 m a.s.l., 11.XII.1993, E. Piva leg. ; 1 ♂, id., La Bora 1252 V / TV, 110 m a.s.l., 18.XI.2013, D. Bianco & E. Piva leg. ; 1 ♂ 3 ♀, Segusino, Buco delle Salamandre 1387 V / TV, 400 m a.s.l., 8.XII.1996, E. Piva leg. ; 1 ♀, Segusino, digging near Buco delle Salamandre 1387 V / TV, 400 m a.s.l., 25. VI.2008, D. Bianco & E. Piva leg. ; 11 ♂ 5 ♀, Susegana, Castello San Salvatore, 100 m a.s.l., 23.IX.2013. G. Gardini & C. Giusto leg., mixed wood. Veneto: Vicenza Prov. — 1 ♀, Arcugnano, near Trattoria della Moreieta , 350 m a.s.l., 11.IV.1992, E. Piva leg. ; 1 ♀, Arcugnano, grove near Trattoria della Moreieta , 335 m a.s.l., 31.III.1996, G. Peretto & E. Piva leg. ; 2 ♀, Arcugnano, Val Scaranti, digging near Grotta del Lupo 5524 V / VI, 230 m a.s.l., 24. VI.2016, E. Piva leg. ; 1 ♂ 1 ♀, Arcugnano, E slope of Monte Zattolo , 120 m a.s.l., 18.III.2012, E. Piva leg. ; 1 ♀, Arcugnano, Villabalzana, small valley near Casa Rappo , 230 m a.s.l., 30.X.2011, E. Piva leg. ; 1 ♂, Montecchio Maggiore, Covolo Basso, digging near the cave L’Infangatoio n.c. V / VI, 19. V.2015, D. Bianco leg. ; 1 ♂ 2 ♀, Schio, Colletto Grande , military gallery at 880 m a.s.l., 15.IX.2005, D. Bianco leg. ; 1 ♀, Schio, Munari , 200 m a.s.l., 22.VII.2010, D. Bianco leg. ; 1 ♀, Valdagno, San Quirico, Pellichero , 475 m a.s.l., 15. VI.2006, D. Bianco leg. ; 1 ♂, Valdagno, Grendene , 610 m a.s.l., 11.IV.2015, D. Bianco leg. , soil washing; 1 ♀, id., 620 m a.s.l., 14.IV.2017, E. Piva leg.; 4 ♀, Valdagno, Valle del Boia , 440 m a.s.l., 11. V.2009, D. Bianco & G. Martini leg. , soil washing; 1 ♀, id., 28. V.2009, D. Bianco leg., digging; 1 ♀, Valdagno, SE slope of Monte Scandolara , 745 m a.s.l., 14.IV.2017, D. Bianco leg. , soil washing; 1 ♀, Valdagno , id., 18.IV.2017, D. Bianco & E. Piva leg. , soil washing; 1 ♀, id., 22.IV.2017, D. Bianco leg., soil washing; 1 ♀, Velo d’Astico, Pozzo Cima Alta n.c. V / VI, 1629 m a.s.l., 27.IX.2015, D. Bianco, P. Falsirollo & E. Filippi leg. Veneto: Verona Prov. — 2 ♂ 2 ♀ ( C. ischnocheles , det. G. Lazzeroni; together with 1 ♂ 1 ♀ of C. densedentatus ), Grezzana, slope N of Vajo del Paradiso, 27.III.1968, G. Osella leg. ( MSNV) ; 1 ♀, Marano di Valpolicella, near Marezzane , 550 m a.s.l., 3. VI.2007, A., M. Zanetti leg. , mixed wood; 1 ♀, Selva di Progno, Giazza, Vallo di Rivolto , 1100 m a.s.l., 13.VII.2007, D. Bianco leg. ; 1 ♂ ( C. ischnocheles , det. G. Lazzeroni), Tregnago, Giazza , 8. V.1968, G. Lazzeroni leg. ( MSNV).

Description of adults (♂ ♀). Integument slightly pigmented, carapace, tergites, chelicerae and pedipalps pale brown; weak hispid granulation on lateral surface of carapace, cheliceral palm, base of fixed chelal finger and on dorso-distal surface of chelal hand. Carapace ( Fig. 4 ) almost square, moderately constricted posteriorly, 0.8–0.9 times longer than broad; anterior margin between median macrosetae strongly denticulate, rarely with prominent epistome in both sexes ( Figs 1–3 ); ocular area as in fig. 4, anterior eyes reduced, with flat lens and tapetum, posterior ones absent or as vestigial remains; standard chaetotaxy m 4m:6:4:2:2(20), anterior row rarely with mm 4m or mm 4mm; length of anteromedian macrosetae 0.095 –0.145 mm. Chaetotaxy of tergites 4:4:4:4:6:6:6:6:1T2T1:4:1 T2T1:0. Standard chaetotaxy of sternites II–X: 10:(3)8–10(3):(2)7–9(2):8:6–8:6:6:6:2T1T2, sternite II rarely with 9 or 11 setae; genital opening of males flanked by 6–7 (rarely 5) setae on each side. Chelicerae ( Fig. 5 ) 2.1–2.3 (♂ ♀) times as long as broad, palm with 6 setae and 1 (rarely 2) lateral microseta; fixed finger with 2 distal large teeth followed by 7–10 small teeth proximally reduced in size and 3–5 proximal microtubercles; movable finger with an isolated subapical tooth (di) at level of the spinneret, followed by a large tooth and 7–12 teeth proximally reduced in size; gs ratio 0.52–0.59; spinneret weakly raised and rarely rounded in males ( Figs 5, 7 ), more prominent and rounded in females ( Fig. 6 ); rallum with 11 blades (12 in ♀ from Piancavallo, 3.VII.1983); serrulae interior and exterior with 14 and 15 blades respectively. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5, IV 6 (coxa I with 2 + 4 marginal microsetae in ♂ from Arcugnano, Mt. Zattolo); coxa II with 5–11 (mainly 6–8) coxal spines, coxa III with 3–6 (mainly 4–5) coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 4.5–5.6 (♂ ♀) times as long as broad, femoral chaetotaxy 3:5:2:5(6):1; chela ( Figs 10, 14 ) 5.0–6.1 (♂) or 4.55–5.6 (♀) times as long as deep; hand of chela 1.55–1.9 (♂) or 1.5–1.75 (♀) times as long as deep, with elongated oval outline in dorsal view ( Figs 8–9 ); fixed chelal finger with 34–55 teeth inclined backwards: 7–12 small, contiguous and pointed distal teeth, proximally increasing in size, followed by large, sharp, reclined and widely spaced teeth ( Figs 18–25 ), decreasing in size from trichobothrium est towards finger base; 6–20 proximal teeth low, more contiguous, rounded, gradually reduced in size ( Figs 11–13, 15–17 ); all teeth with dental canal; fixed finger at level of est-it with 5–9 (♂) or 4–7 (♀) teeth occupying 0.1 mm, distance between successive apices 0.012 –0.027 (♂) or 0.011 –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 30–47 teeth, slightly scalene triangle-shaped, reclined and apically pointed proximally up to trichobothrium st, rounded and increasingly reduced from st towards finger base, reaching back near b (between sb and b they are mainly recognizable only by the presence of dental canal) ( Figs 11–13, 15–17 ); movable finger at level of st-t with 6–9 (♂) or 5–8 (♀) teeth occupying 0.1 mm, distance between successive apices 0.011 –0.019 (♂) or 0.011 –0.023 (♀) mm; coupled sensilla pc just distad of sb and on a noticeable tubercle; tip of movable chelal finger with apical sensilla am 1- 2; trichobothria as in figs 10, 14; ratio sb -st/sb -b = 1.5–1.9; ratio of movable finger/hand of chela 2.0–2.3 (♂ ♀); ratio of pedipalpal femur/movable finger 0.9–1.0 (♂ ♀); ratio of pedipalpal femur/carapace 1.2–1.5 (♂ ♀).

Measurements (in mm). Body length 1.0–1.5 (♂) or 1.1–1.7 (♀). Carapace 0.30–0.43 × 0.35–0.47 (0.32–0.45 anteriorly) (♂) or 0.32–0.50 × 0.40–0.53 (0.37–0.51 anteriorly) (♀). Chelicerae 0.31–0.43 × 0.14–0.20 (♂) or 0.36–0.50 × 0.17–0.23 (♀); movable finger length 0.16–0.23 (♂) or 0.18–0.26 (♀). Pedipalp: femur 0.36–0.60 × 0.08–0.11 (♂) or 0.40–0.65 × 0.09–0.12 (♀); chela 0.56–0.93 × 0.105–0.16 (♂) or 0.605–1.08 × 0.125 –0.215 (♀); hand length 0.175 –0.295 (♂) or 0.195–0.35 (♀); movable finger length 0.39–0.62 (♂) or 0.42–0.74 (♀).

Remarks. Chthonius agazzii was described by Beier (1966) from four females and one male from Veneto (Cave La Bislonga 1001 V /TV, Pederobba, and Bus de le Fave 1272 V /TV, Refrontolo, respectively). The types of C. agazzii are still not traceable (see also Gardini 1998). Beier (1966) highlighted the presence of one microseta on each side of carapacal basal series in male, that are absent in females. The examination of five females from the cave Bus de le Fave (4.X.1985, S. Zoia, R. Sciaky & E. Piva leg.; 5.I.1991, E. Piva leg.) allows me to attribute the same to C. ischnocheloides Beier, 1973 , a hypogean species that is widespread in the same geographical area as C. agazzii and belongs to the C. orthodactylus-tenuis group according to the arrowhead-shaped distoparaxial seta on the fixed chelal finger. It is therefore almost certain that the male paratype of C. agazzii belongs to C. ischnocheloides .

The cave Buco delle Salamandre 1387 V / TV, Segusino, from which the illustrated male and female were collected, is only 5.5 km away from the cave La Bislonga, the type locality of C. agazzii .

Chthonius malatestai was described by Callaini (1980a) from a male and two females from Veneto [♂ ♀, Monte Pizzoc, Fregona (loc. typ.); ♀, Passo di San Boldo, Cison di Valmarino] and compared with Chthonius ressli Beier, 1956 and C. agazzii . Following Callaini (1980a), Chthonius malatestai should differ from C. agazzii in having smaller size, less slender pedipalps and in the shape of chelal teeth. Fig. 18 reproduces dentition of the distal half of chelal fingers in male holotype of C. malatestai .

The specimens examined share, with rare exceptions (see the above Description of adults), the same chaetotaxy of carapace (m 4m:6:4:2:2), the presence of one lateral microseta on the cheliceral palm, the chelal fingers with the same tooth pattern (fixed finger distally with small, reclined and contiguous teeth, becoming more widely spaced proximally), coupled sensilla pc always distad of sb (between the sixth and tenth teeth) and placed on a noticeable tubercle; but at the same time they have wide inter-populational variability in size, which does not seem to follow any geographical or adaptive gradient. Large specimens usually have more widely spaced chelal teeth while smaller specimens have closer up teeth, as evident in specimens from Buco delle Salamandre ( Figs 10–17 ) and Mt. Pizzoc ( Fig. 18 ) respectively. The continuum of variability in the dentition of the chelal fingers is represented in figs 18–25.

In view of the above, Chthonius malatestai Callaini, 1980 is proposed here as a junior subjective synonym of Chthonius agazzii Beier, 1966 (n. syn.).

Pedipalpal measurements of specimens of Chthonius agazzii from Cansiglio, Veneto ( Callaini 1980a) fall within the range of variability reported in the above description of the species. The doubtful quotation of C. agazzii from the cave Cevola dei Battei 245 Fr/PN, Friuli ( Gardini 1991) must be referred to C. ischnocheloides .

Among the species of the Chthonius ischnocheles group, C. agazzii is morphologically very close to C. paolettii Beier, 1973 , a hypogean species from Veneto. Chthonius agazzii differs from C. paolettii in the following characters (comparison among females): chela length 0.605–1.08 mm (1.10–1.15 mm in C. paolettii ); movable chelal finger length 0.42–0.74 mm (0.74–0.77 mm in C. paolettii ); fixed and movable chelal fingers at level of est–ist and st–t, respectively, with 4–7 and 5–8 teeth occupying 0.1 mm, distance between successive apices 0.011 –0.032 and 0.011 –0.023 mm respectively (with 3 and 5 teeth occupying 0.1 mm, distance between successive apices 0.035 and 0.025 mm, respectively, in C. paolettii ); movable chelal finger with coupled sensilla pc on a noticeable tubercle (coupled sensilla pc lodged not on a tubercle in C. paolettii ).

Chthonius agazzii is also morphologically similar to C. comottii Inzaghi, 1987 , an epigean or locally hypogean species from the western Alps. C. agazzii differs from C. comottii in the following characters: anterior margin of carapace rarely with a prominent epistome (mostly with prominent epistome in C. comottii ), posterior margin of carapace with 2 macrosetae, without lateral microsetae (with one microseta on each side in C. comottii ); chelicerae with 1 (rarely 2) lateral microseta (with 2 lateral microsetae in C. comottii ).

Chthonius agazzii and C. comottii are vicariant in the Alps: the first occurs from Friuli to Trentino and the latter is found from Lombardy to western Liguria.

Figures

FIGURES 1–9. Chthonius agazzii Beier, 1966, Buco delle Salamandre (Segusino, Treviso) (unless otherwise stated). 1, male, anterior margin of carapace; 2, female, id.; 3, male, (Grotta Faller, Sovramonte, Belluno), id.; 4, male, carapace; 5, male, right chelicera; 6, female, movable finger of right chelicera; 7, male, (Le Vette Feltrine, Pedavena, Belluno), id.; 8, male, right chelal hand, dorsal view; 9, female, id.

FIGURES 10–17. Chthonius agazzii Beier, 1966, Buco delle Salamandre (Segusino, Treviso). 10, male, right chela, antiaxial view; 11, male, detail of fingers at the chelal tip, antiaxial view; 12, male, detail of fingers at level of trichobothria est-it and st-t, antiaxial view; 13, male, detail of fingers at level of trichobothrium sb, antiaxial view; 14, female, right chela, antiaxial view; 15, female, detail of fingers at the chelal tip, antiaxial view; 16, female, detail of fingers at level of trichobothria est-it and st-t, antiaxial view; 17, female, detail of fingers at level of trichobothrium sb, antiaxial view.

FIGURES 18–25. Chthonius agazzii Beier, 1966, detail of dentition at the chelal fingers tip, antiaxial view (setae and sensilla af1-2, am1-2 omitted). 18, male holotype of C. malatestai, Mt. Pizzoc (Fregona, Treviso); 19, male, Milies (Treviso); 20, female, Pozzo Cima Alta (Velo d’Astico, Treviso); 21, female, near Trattoria della Moreieta (Arcugnano, Vicenza); 22, female, near Marezzane (Marano di Valpolicella, Verona); 23, male, Bus dei Tedeschi (San Pietro di Feletto, Treviso); 24, female, slope of Mt. Faverghera (Belluno); 25, female, near Buco delle Salamandre (Segusino, Treviso).

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.