Chthonius

Gardini, Giulio, 2013, A revision of the species of the pseudoscorpion subgenus Chthonius (Ephippiochthonius) (Arachnida, Pseudoscorpiones, Chthoniidae) from Italy and neighbouring areas, Zootaxa 3655 (1), pp. 1-151: 50-52

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http://dx.doi.org/10.11646/zootaxa.3655.1.1

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http://treatment.plazi.org/id/03DE87C1-FFDA-F950-6B99-FC7B1B36A6C4

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scientific name

Chthonius
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Chthonius   (E.) gestroi   Simon, 1896

( Figs 89–93 View FIGURES 89 – 93 , 291 View FIGURES 290 – 293 )

Chthonius (Ephippiochthonius) gestroi: Beier 1932: 59   , fig. 73; Gardini 1990: 232, figs 1–8.

Type locality: Liguria, Savona Prov., Finale Ligure, Arma Pollera 24 Li/SV (44 ° 11 ʹ 58 ʺN 8 ° 18 ʹ 54 ʺE).

Distribution. Italy: Liguria.

Diagnosis (Ƥ). An anophthalmic hypogean Chthonius   ( Ephippiochthonius   ) from western Liguria that differs from other species of the C. fuscimanus   group in the following combination of characters: highly specialized troglomorphic facies; movable cheliceral finger with the isolated subapical tooth (di) at level with the spinneret; both sexes with prominent spinneret; pedipalpal hand (in lateral view) without a rounded hump distad of trichobothria ib-isb, rarely weakly depressed at level of ib-isb; pedipalpal fixed finger at level of est-it with 2–3 teeth occupying 0.1 mm (distance between successive apices 0.040 mm); distal half of movable chelal finger with 11–14 triangular teeth, proximal half with thick and weakly undulated marginal lamina; length of chela 1.50–1.70 (3), 1.65–1.86 (Ƥ) mm, length of movable chelal finger 0.86–0.96 (3), 0.955–1.07 (Ƥ) mm; chela 7.5–8.1 (3), 7.25–8.45 (Ƥ) times as long as deep; ratio of pedipalpal femur/carapace 1.8–2.05 (3 Ƥ).

Type material examined. ITALY — Liguria: Savona Prov. — 1 3 (holotype), “ Chthonius Gestroi E. S.   typus! / Gr. Pollera R. Barberi” [Finale Ligure, Arma Pollera 24 Li/SV, 284 m a.s.l.] (MSNG).

Other material examined. ITALY — Liguria: Savona Prov. — 1 Ƥ, Borgio Verezzi, Grotta di Valdemino 160 Li/SV, 30 m a.s.l., 7.II. 1979, C. Bonzano leg.; 4 Ƥ 1 T, id., 5.X. 1981, S. Zoia leg.; 31 3 2 Ƥ, “Grotta Pollera, 12.IV. 1897, Solari” [id., Arma Pollera 24 Li/SV, 284 m a.s.l.] (MSNG); 1 3, “Gr. Pollera, 14.IV. 1897, A. Dodero” [id.] (MSNG); 1 3, id., Arma Pollera 24 Li/SV, 284 m a.s.l., 27.XI. 1967, A. Vigna leg. (MSNV); 1 Ƥ, id., 3.XI. 1974, L. Briganti, G. Gardini & S. Zoia leg.; 1 3, id., 4.I. 1981, Gruppo Entomologico Ligure leg.; 1 Ƥ, id., 7.XII. 1981, S. Zoia leg.; 1 3, id., 17.I. 1982, S. Durante leg.; 1 Ƥ, id., Grotta di S. Antonino 30 Li/SV, 283 m a.s.l., 17.I. 1988, S. Zoia leg.; 1 Ƥ 1 T “ Gr. Arene Candide, 26.Ag. 1897, Solari leg. [id., Arma de Arene Candide 34 Li/ SV, 110 m a.s.l.] (MSNG); 1 Ƥ (M. Beier det., C. Menozzi det.), “Gr. Arene Candide n. 34 Li ( Sala Solari), Finale Lig., 10.III. 1935, F. Capra leg.” [id.] (MSNG).

Description of adults (Ƥ). Highly specialized troglomorphic facies. Integument without pigmentation; hispid granulation on lateral surfaces of carapace and on cheliceral palm. Carapace 1.0– 1.1 times as long as broad, posteriorly constricted; anterior margin (fig. 89) closely dentate between median macrosetae, weakly prominent in females, without epistome; no eyes or eye-spots; chaetotaxy mm 4mm: 6: 4: 2: 2 (18), microsetae fine; length of anteromedian macrosetae 0.16–0.18 mm. Chaetotaxy of tergites I –X 4: 4: 4: 4: 6: 6: 6: 6: 6: 4. Chaetotaxy of sternites II –X 10:(3) 7–10 (3):(2) 7–9 (2): 7 or 9: 6: 6: 6: 6: 7; genital opening of males flanked by 8–10 setae on each side. Chelicerae (fig. 90) 2.4–2.5 times as long as broad, palm with 6 setae and 1–4 microsetae laterally; fixed finger with 15–20 subequal teeth proximally reduced in size; movable finger with isolated subapical tooth (di) at level with the spinneret and with 8–12 teeth proximally reduced in size; gl ratio 0.55–0.60; spinneret small, tooth-shaped in males, larger in females; rallum with 11 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 (rarely 4) + 3 marginal microsetae, II 4 (rarely 5), III 5, IV 6; coxa II with 15–18 coxal spines, coxa III with 6–8 coxal spines; intercoxal tubercle bisetose (rarely trisetose). Pedipalp: femur 9.0– 9.5 (3), 8.6–10.7 (Ƥ) times as long as broad; chela (figs 91–93) 7.5–8.1 (3), 7.25–8.45 (Ƥ) times as long as deep; hand of chela 3.1–3.3 (3), 3.0– 3.5 (Ƥ) times as long as deep, weakly depressed at level of ib-isb; fixed chelal finger with 18–21 triangular pointed teeth, except for the first 1–3 proximal ones, with rounded tip, all with dental canals; base of fixed finger with 5–8 microtubercles; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; fixed chelal finger al level of est-it with 2–3 teeth occupying 0.1 mm (distance between successive apices 0.040 mm); distal half of movable finger with 11–14 upright, triangular teeth, the first 1–3 proximal ones sometimes reduced, rounded, all with dental canals; proximal half of movable chelal finger with thick marginal lamina mostly straight, sometimes weakly irregularly undulated; coupled sensilla pc variably placed between sb and halfway between b and sb; trichobothria as in figs 92–93, eb-esb-ist placed in a straight line or ist a little proximad of the line eb-esb; basal apodeme of movable finger strongly sclerotized, rectangular and fine; ratio of movable finger/hand of chela 1.35–1.4 (3 Ƥ); ratio of pedipalpal femur/movable finger 1.2–1.35 (3 Ƥ); ratio of pedipalpal femur/carapace 1.8–2.05 (3 Ƥ).

Measurements (in mm). Body length 1.9–2.3 (3), 2.0– 2.45 (Ƥ). Carapace 0.57–0.61 × 0.54–0.59 (3), 0.64– 0.70 × 0.61–0.66 (Ƥ). Chelicerae 0.54–0.61 × 0.22–0.25 (3), 0.64–0.69 × 0.26–0.28 (Ƥ), movable finger length 0.27–0.31 (3), 0.33–0.37 (Ƥ). Pedipalp: femur 1.08–1.22 × 0.12–0.13 (3), 1.21–1.44 × 0.13–0.14 (Ƥ); chela 1.50– 1.70 × 0.19–0.21 (3), 1.65–1.86 × 0.22–0.24 (Ƥ); hand length 0.61–0.70 (3), 0.68–0.78 (Ƥ); movable finger length 0.86–0.96 (3), 0.955–1.07 (Ƥ).

Description of tritonymph. Integument without pigmentation, with weak hispid granulation. Carapace 1.1 times longer than broad; no eyes or eye-spots and no epistome; chaetotaxy m 4m: 6: 4: 2: 2 (18). Chaetotaxy of tergites as in adults. Chaetotaxy of sternites II –X 5:(2) 8 (2):(1) 6 (1): 7: 6: 6: 6: 6: 7. Cheliceral palm with 5 setae and 2 lateral microsetae; spinneret as in females. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 2 marginal microsetae, II 4, III 5, IV 5; intercoxal tubercle bisetose. Pedipalp: chela (see Gardini 1990, fig. 7) 7.0– 7.5 times as long as deep; hand of chela 2.8 –3.0 times as long as deep; fixed chelal finger with 16–19 triangular teeth, of which the first 1–2 distal ones are reduced and apically rounded; base of fixed finger with 7–8 microtubercles; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; distal half of movable finger with 9–10 triangular teeth; coupled sensilla pc a little distad of b; ratio movable finger/hand of chela 1.4–1.5.

Measurements of pedipalps (in mm). Chela 1.05–1.16 × 0.15–0.155; hand length 0.42–0.47; movable finger length 0.63–0.67.

Remarks. Among the species of the Chthonius fuscimanus   group, C. gestroi   is related to the epigean C. nanus   , a widespread species in the same geographical area, from which it clearly differs in troglomorphic characters.

C. gestroi   was redescribed from type material by Gardini (1990). It is related to the hypogean C. troglophilus   from the Maritime and Ligurian Alps and pre-Alps, from which it differs in the stronger troglomorphic facies: length of chela 1.50–1.70 mm (3) 1.65–1.86 (Ƥ) mm in C. gestroi   , 1.0– 1.29 mm (3) 0.77–1.39 (Ƥ) mm in C. troglophilus   ; in the more elongated appendages (chela 7.5–8.1 (3) 7.25–8.45 (Ƥ) times as long as deep in C. gestroi   , 6.7–7.6 (3) 5.45–6.9 (Ƥ) times as long as deep in C. troglophilus   ) and in the dentition of the fixed chelal finger with 18–21 teeth, at level of est-it with 2–3 teeth occupying 0.1 mm (distance between successive apices 0.040 mm) in C. gestroi   , as opposed to 13–17 teeth, at level of est-it with 3–4 teeth occupying 0.1 mm (distance between successive apices 0.027–0.031 mm), in C. troglophilus   .