Chthonius lanai, Gardini, 2021

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 : 95-98

Chthonius lanai n. sp.

( Figs 297–308 , 413 )

Type locality: Italy, Piedmont, Cuneo Province, Bernezzo, Pertus d’la Kassetta 1323 Pi / CN (44°23’02”N, 7°23’01”E) .

Distribution. Italy (Piedmont).

Diagnosis (♂ ♀). An anophthalmic hypogean Chthonius that differs from other species of the ischnocheles group in the following combination of characters: anterior margin of carapace without or with 1 or 2 preocular microsetae; posterior margin of carapace with 2 macrosetae and 1 lateral microseta on each side; chelicerae with 2 lateral microsetae; tergite I with 2 setae; chela length 1.71–1.74 mm; movable chelal finger length 1.18–1.20 mm; fixed chelal finger straight; chelal fingers with reclined, pointed and widely spaced teeth; fixed and movable chelal fingers with 60–64 and 49–52 teeth, respectively; both fixed and movable chelal fingers at level of est-ist and st-t with 5–6 teeth occupying 0.1 mm, distance between successive apices 0.016 –0.023 mm; ratio of pedipalpal femur/ carapace 1.9.

Type material. ITALY — Piedmont: 1 ♀ (holotype) 2 ♀ (paratypes), Cuneo Prov., Bernezzo, Vallone del Cugino, Pertus d’la Kassetta 1323 Pi / CN, 1230 m a.s.l., 23.II.2020, E. Lana leg. ; 1 ♂ (paratype), id., 15.VI.2013, E. Lana & M. Chesta leg. (holotype deposited in MHNG, paratypes in G. Gardini coll., Genoa) .

Derivatio nominis. Named after the naturalist and biospeleologist Enrico Lana (Biologia Sotterranea Piemonte, Gruppo di Ricerca and Struttura Operativa Bossea, Club Alpino Italiano), in recognition of his contribution to the knowledge of the subterranean fauna of Piedmont.

Description of adults (♂ ♀). Integument slightly pigmented, chelicerae and chelal fingers reddish brown pale; hispid granulation on the lateral surfaces of carapace, on cheliceral palm and on the base of fixed chelal finger. Carapace ( Fig. 299 ) 0.90–0.95 times longer than broad, trapezoidal, constricted posteriorly; anterior margin strongly denticulate between the median macrosetae, without a prominent epistome ( Figs 297–298 ); ocular area as in fig. 299, anterior eyes reduced to a hardly noticeable cuticular pale area, posterior eyes absent; probable standard chaetotaxy m 4m:6:4:2:m 2m (22), anterior row also m4 or mm4, or without preocular microsetae (♀ holotype: fig. 299), length of anteromedian macrosetae 0.18–0.20 mm. Chaetotaxy of tergites 2:3:4:4:6:6:6:6:1T2T1:4:1T2T1:0, tergites II 2 (1 ♀), IV 3 (1 ♀), V 5 (2 ♀). Chaetotaxy of sternites II–X: 10–12:(3)8(3):(2)7–8(2):7–8:6:6:6:6:2T1T2; genital opening of male flanked by 9 setae on each side. Chelicerae ( Fig. 300 ) 2.5 times as long as broad, palm with 6 setae and 2 lateral microsetae; fixed finger with 2 distal large teeth followed by 8–10 small teeth proximally increasingly reduced and 4–7 microtubercles; movable finger with an isolated subapical tooth (di) at level with the spinneret (♂) or more proximal with respect to the spinneret (♀), followed by a large tooth and 9–10 teeth that are proximally reduced in size; gs ratio 0.53–0.55; spinneret small, right angle-shaped in male, prominent and hemispherical in females ( Figs 300–301 ); rallum with 11 blades; serrula interior with 14, exterior with 18 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I (3)4 + 3(4) marginal microsetae, II (4)5, III 5(6), IV 6; coxa II with 16–17 coxal spines, coxa III with 6–8 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 8.9 (♂) or 7.55 (♀) times as long as broad, femoral chaetotaxy 3:5:3:(5)6:1; chela ( Figs 304, 308 ) 7.25 (♂) or 7.1–7.25 (♀) times as long as deep; hand of chela 2.3 (♂) or 2.25–2.3 (♀) times as long as deep, with parallel outline in dorsal view ( Figs 302–303 ); fixed chelal finger straight, with 60–64 teeth inclined backwards: the 9–12 distal teeth pointed, thin and contiguous, followed by 44–46 reclined, pointed teeth that are increasingly widely spaced towards finger base and 8–10 proximal teeth that are low, rounded, and reduced in size ( Figs 305–307 ); all teeth with dental canal; base of fixed chelal finger with 4–8 microtubercles; fixed finger at level of est-it with (5)6 teeth occupying 0.1 mm, distance between successive apices 0.018 (♂) or 0.016 –0.018 (♀) mm; tip of fixed chelal finger with apical sensilla af 1- 2, distal paraxial seta gradually curved and thin; movable chelal finger with 49–52 teeth that are large, squat, reclined apically, increasingly reduced towards finger base in the proximal half of the finger, and reaching back nearby b ( Figs 305–307 ); movable finger at level of st-t with 5 teeth occupying 0.1 mm, distance between successive apices 0.020 –0.023 (♂ ♀); coupled sensilla pc at level of sb or just distad sb; tip of movable chelal finger with apical sensilla am 1- 2; trichobothria as in figs 304, 308; ratio sb -st/sb -b = 1.85 (♂) or 1.5–1.7 (♀); ratio of movable finger/hand of chela 2.15–2.2 (♂ ♀); ratio of pedipalpal femur/movable finger 1.2 (♂) or 1.0 (♀); ratio of pedipalpal femur/carapace 1.9 (♂ ♀).

Measurements (in mm). Body length 2.15–2.0 (♂ ♀). Carapace 0.62 × 0.68 (0.66 anteriorly) (♂) or 0.64 × 0.66–0.67 (0.63–0.64 anteriorly) (♀). Chelicerae 0.74 × 0.29 (♂) or 0.74 × 0.29 (♀); movable finger length 0.37 (♂) or 0.37–0.38 (♀). Pedipalp: femur 1.47 × 0.165 (♂) or 1.21 × 0.16 (♀); chela 1.74 × 0.24 (♂) or 1.71–1.74 × 0.24 (♀); hand length 0.56 (♂) or 0.54–0.55 (♀); movable finger length 1.20 (♂) or 1.18–1.20 (♀).

Remarks. Among the species of the Chthonius ischnocheles group, C. lanai is morphologically very close to the subterranean C. italicus from the south-western Alps.

Chthonius lanai n. sp. differs from C. italicus in the following characters: anterior eyes reduced to a smooth cuticular area (no eyes in C. italicus ); chaetotaxy of tergites I–IV 2:2–3:4:4 [(2–3)4:3–4:4: 4 in C. italicus ]; fixed chelal finger straight (slightly curved in C. italicus ); fixed and movable chelal fingers with larger and more widely spaced teeth ( Figs 305–307 ) [with smaller and more close-set teeth ( Figs 275–277, 279–281 ) in C. italicus ].

Figures

FIGURES 297–303. Chthonius lanai n. sp. 297, female holotype, anterior margin of carapace; 298, male paratype, id.; 299, female holotype, right half of the carapace; 300, female holotype, right chelicera; 301, male paratype, movable finger of right chelicera; 302, male paratype, right chelal hand, dorsal view; 303, female holotype, id.

FIGURES 304–308. Chthonius lanai n. sp. 304, female holotype, right chela, antiaxial view; 305, female holotype, detail of fingers at the chelal tip, antiaxial view; 306, female holotype, detail of fingers at level of trichobothria est-it and st-t, antiaxial view; 307, female holotype, detail of fingers at level of trichobothrium sb, antiaxial view; 308, male paratype, right chela, antiaxial view.

FIGURES 410–413. Distribution maps for the Italian species of the Chthonius ischnocheles group. 410, Chthonius caoduroi Callaini, 1987, Chthonius gallettii n. sp., Chthonius inguscioi n. sp., Chthonius marciai n. sp. and Chthonius multidentatus Beier, 1963; 411, Chthonius caprai Gardini, 1977, Chthonius jonicus Beier, 1931 and Chthonius leoi (Callaini, 1988); 412, Chthonius halberti Kew, 1916, Chthonius nicolosii n. sp., Chthonius ressli Beier, 1956 and Chthonius stammeri Beier, 1942; 413, Chthonius horridus Beier, 1934, Chthonius italicus Beier, 1930 and Chthonius lanai n. sp.

FIGURES 274–281. Chthonius italicus Beier, 1930, Grotta dei Surgentin, 29.III.2015 (Pigna, Imperia). 274, male, right chela, antiaxial view; 275, male, detail of fingers at the chelal tip, antiaxial view; 276, male, detail of fingers at level of trichobothria est-it and st-t, antiaxial view; 277, male, detail of fingers at level of trichobothrium sb, antiaxial view; 278, female, right chela, antiaxial view; 279, female, detail of fingers at the chelal tip, antiaxial view; 280, female, detail of fingers at level of trichobothria est-it and st-t, antiaxial view; 281, female, detail of fingers at level of trichobothrium sb, antiaxial view.