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: 136-140

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

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http://treatment.plazi.org/id/03DE87C1-FF6C-F9E8-6B99-FB501CC8A26F

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scientific name

Chthonius
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Chthonius   (E.) vachoni   Heurtault-Rossi, 1963

( Figs 261–269 View FIGURES 261 – 267 View FIGURES 268 – 269 , 283 View FIGURES 282 – 285 )

Chthonius (Ephippiochthonius) vachoni Heurtault-Rossi 1963: 419   , figs 1–14.

Type locality: France, Gironde, Taussat-les-Bains (44 ° 43 ʹN 1 °04ʹW).

Distribution. Mainland France, Italy: western Liguria.

Diagnosis (Ƥ). An eyed epigean Chthonius   ( Ephippiochthonius   ) that differs from other species of the C. tetrachelatus   group in the following combination of characters: movable cheliceral finger without isolated subapical tooth (di), with spinneret in both sexes (rarely reduced in males); posterior margin of carapace with 2 macrosetae and 1 lateral microseta on each side; hand of chela weakly depressed at level of trichobothria ib-isb and with hump distad of ib-isb; fixed chelal finger at level of est-it with 5–6 teeth occupying 0.1 mm (distance between successive apices 0.020 mm); distal half of movable chelal finger with 6–8 large, triangular, pointed teeth, proximal half with vestigial, widely rounded teeth reduced as far as trichobothrium sb; length of chela 0.51–0.56 (3), 0.54–0.62 (Ƥ) mm, length of movable finger 0.30–0.33 (3), 0.31–0.35 (Ƥ) mm; chela 4.6–5.1 (3), 4.1–4.5 (Ƥ) times as long as deep; ratio of pedipalpal femur/carapace 1.1–1.25 (3 Ƥ).

Material examined. FRANCE— Alpes Maritimes— 1 3 1 Ƥ, Coursegoules, N Greolières, 1200 m a.s.l., 29.IV. 2003, S. & F. Zoia leg.; 1 3, near Grasse, 20.VIII. 1983, S. Zoia & C. Torti leg.; 26 3 18 Ƥ 13 T, road from Grasse to Digne, 4 km beyond Pas de la Faye, 20.VIII. 1983, S. Zoia & C. Torti leg.; 1 3, La-Colle-sur-Loup, Le Vallon Rouge, 11.II. 1994, M. Bodon leg. Var— 2 Ƥ, Draguignan, Figanière, 1–2.V. 1975, S. Zoia leg., sieved in garigue; 1 3, Toulon, Chartreuse de Montrieux, 8.XII. 1992, G. Gardini & S. Zoia leg., Quercus   wood; 1 3 2 Ƥ, id., near Revest, 600 m a.s.l., 7.XII. 1992, G. Gardini & S. Zoia leg., Quercus ilex   wood.

ITALY— Liguria: Genoa Prov.— 1 3 3 D, Cogoleto, Lerca, 26.II. 2006, V. Vercelli leg. Liguria: Imperia Prov.— 3 3 1 Ƥ 1 T, Ventimiglia, Mortola, 9.I. 1975, G. Gardini leg., sieved in Mediterranean scrub near seaside; 4 3 3 Ƥ 2 T 1 D, id., Mortola, 150 m a.s.l., 16.V. 1976, R. Poggi leg., sieved under Pistacia lentiscus   ; 2 3 3 Ƥ 1 T, id., Mortola, Villa Hanbury, 30.III. 1976, G. Gardini leg., sieved under Pistacia   . Liguria: Savona Prov.— 1 3, Alassio, Isola Gallinara W slope, 21.X. 1996, D. Lanteri leg., pitfall trap; 2 3 7 Ƥ 2 T, Bergeggi, Promontorio di Bergeggi, 27.VI. 1975, G. Gardini leg., sieved under Pistacia   ; 1 3 1 Ƥ, Laigueglia, Capo Mele, 24.II. 1974, G. Gardini leg., under stone near seaside; 1 3, id., 28.V. 1974, G. Gardini leg., sieved in garigue; 6 3 3 Ƥ 1 T, id., 6.III. 1975, G. Gardini leg., sieved; 11 3 8 Ƥ 1 T 1 D, id., 230 m a.s.l., 8.I. 1976, G. Bartoli & R. Poggi leg., sieved under Cistus   ; 9 3 7 Ƥ 6 T, id., 23.I. 1976, G. Bartoli & R. Poggi leg., sieved under Rhamnus   and Pistacia   near seaside; 1 3, Varigotti, Capo Varigotti, 31.V. 1975, R. Poggi leg., under stone in olive grove.

Description of adults (Ƥ). Integument pigmented, carapace, tergites, chelicerae and pedipalps brown; hispid granulation on lateral surface of carapace, on cheliceral palm and on the base of movable chelal finger. Carapace 1.0– 1.1 times longer than broad, subquadrate; anterior border (figs 261–262) strongly denticulate between median macrosetae, rarely weakly prominent, without epistome; ocular area as in fig. 263, anterior eyes with convex lens (diameter 0.030–0.035 mm), posterior pair reduced to ocular spots, all eyes with tapetum; distance from anterior eyes to anterior margin of carapace 0.02–0.03 mm; chaetotaxy mm 4mm: 6: 4: 2:m 2m (18), macrosetae short and thick (shorter and thicker in specimens from Promontorio di Bergeggi); rarely one preocular microseta on each side; length of anteromedian macrosetae 0.05–0.07 mm. Chaetotaxy of tergites I –X 4: 4: 4: 4: 6: 6: 6: 6: 6: 4. Chaetotaxy of sternites II –X 10:(3) 8–10 (3):(2) 7–9 (2): 8: 6: 6: 6: 6: 7; sternite II rarely with 9 setae, sternite V rarely with 7 setae; genital opening of males flanked by 6–7 (rarely 4 or 5) setae on each side. Chelicerae (figs 264–266) 2.0– 2.1 times as long as broad, palm with 6 setae and 2 microsetae laterally; fixed finger with 5–7 subequal teeth and 3–7 proximal microtubercles; movable finger with 3–5 teeth and 3–6 proximal microtubercles, isolated subapical tooth (di) absent; gl ratio 0.57–0.65; spinneret prominent in both sexes (reduced in a male from Mortola: fig. 265), apically widely rounded; rallum with 11 blades; serrulae interior and exterior respectively with 12 and 14 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5, IV 6; coxa II with 4–10 coxal spines, coxa III with 2–5 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 4.75 –5.0 (3), 4.55–5.1 (Ƥ) times as long as broad; chela (figs 267–269) 4.6–5.1 (3), 4.1–4.5 (Ƥ) times as long as deep; hand of chela 1.9–2.1 (3), 1.7–1.9 (Ƥ) times as long as deep, weakly depressed at level of trichobothria ib-isb and a wide hump distad of ib-isb; fixed chelal finger with 13–18 teeth: 1–2 distal triangular, small, upright teeth, 12–15 large triangular, pointed, weakly reclined teeth, proximally reduced in size, and 1–3 proximal teeth widely rounded, all teeth with dental canals; base of fixed chelal finger with 3–6 microtubercles; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; fixed chelal finger at level of est-it with 5–6 teeth occupying 0.1 mm (distance between successive apices 0.020 mm); distal three quarters of movable chelal finger with 11–13 teeth: one very small distal tooth (rarely absent), 6–8 large triangular, pointed, upright teeth, and 4–7 proximal vestigial teeth, widely rounded, gradually reduced as far as trichobothrium sb; base of movable chelal finger with a few microtubercles; coupled sensilla pc mostly at level of sb; trichobothria as in figs 268–269, eb-esb-ist usually placed in a straight line, rarely ist distad of the line eb-esb; basal apodeme of movable chelal finger strongly sclerotized, rectangular, squat, indented apically; ratio of movable finger/hand of chela 1.3–1.45 (3), 1.3–1.4 (Ƥ); ratio of pedipalpal femur/movable finger 1.15–1.2 (3 Ƥ); ratio of pedipalpal femur/carapace 1.1–1.25 (3 Ƥ).

Measurements (in mm). Body length 1.1 (3), 1.2–1.3 (Ƥ). Carapace 0.30–0.34 × 0.29–0.34 (0.26–0.30 anteriorly) (3), 0.33–0.37 × 0.32–0.36 (0.28–0.33 anteriorly) (Ƥ). Chelicerae 0.25–0.27 × 0.12–0.135 (3), 0.26– 0.315 × 0.13–0.15 (Ƥ); movable finger length 0.125–0.135 (3), 0.135–0.16 (Ƥ). Pedipalp: femur 0.345–0.38 × 0.07–0.08 (3), 0.37–0.42 × 0.08–0.09 (Ƥ); chela 0.51–0.56 × 0.10–0.12 (3), 0.54–0.62 × 0.12–0.15 (Ƥ); hand length 0.21–0.24 (3), 0.23–0.26 (Ƥ); movable finger length 0.30–0.33 (3), 0.31–0.35 (Ƥ).

Description of tritonymph. Integument with weak pigmentation, hispid granulation less marked than in adults. Carapace 1.0 times longer than broad, eyes as in adults; chaetotaxy m 4m: 6: 4: 2:m 2m (18); length of anteromedian macrosetae 0.05 mm. Chaetotaxy of tergites as in adults. Chaetotaxy of sternites II –X 5:(2) 6 (2):(1) 6 (1): 7–8: 6: 6: 6: 6: 7. Chelicerae 1.95–2.1 times as long as broad, palm with 5 setae and one microseta laterally; fixed finger with 4–5 teeth and 3–4 proximal microtubercles; movable finger with 3–4 teeth and about 3 proximal microtubercles, without isolated subapical tooth (di); gl ratio 0.57–0.64; rallum with 9 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 2 marginal microsetae, II 4, III 5, IV 5; coxa II with 5–7 coxal spines, coxa III with 3–4 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 4.6 –5.0 times as long as broad; chela 4.3–4.5 times as long as deep; hand of chela 1.7–1.9 times as long as deep; fixed chelal finger with 14–18 teeth, the 3–6 proximal ones vestigial, widely rounded; tip of fixed chelal finger with a modified accessory tooth (td) on antiaxial face; movable chelal finger with 10–11 teeth, the 2–4 proximal ones vestigial; coupled sensilla pc distad with respect to b; ratio of movable finger/hand of chela 1.4–1.45; ratio of pedipalpal femur/movable finger 1.1–1.15; ratio of pedipalpal femur/carapace 1.0.

Measurements (in mm). Body length 0.9. Carapace 0.26–0.27 × 0.26–0.27 (0.22 anteriorly). Chelicerae 0.20– 0.205 × 0.095–0.105, movable finger length 0.10. Pedipalp: femur 0.27–0.28 × 0.055–0.06; chela 0.40–0.43 × 0.09–0.10; hand length 0.16–0.18; movable finger length 0.235–0.25.

Remarks. The measurements and proportions given by Heurtault-Rossi (1963) in description of Chthonius vachoni   are unreliable, due to deformation in permanent slides; unpublished measurements and drawings of alcohol-preserved paratypes (3 Ƥ), provided by M. Judson, are consistent with the above description.

Among the species of the Chthonius tetrachelatus   group, C. vachoni   is closely related to the epigean C. siculus   from central and southern Italy, Sicily and Sardinia. For comparisons between C. vachoni   and C. siculus   see Remarks under the latter species.

C. vachoni   was previously known from the type locality (Taussat-les-Bains, Gironde) (Heurtault-Rossi 1963) and Fontan, Alpes Maritimes (Judson 2010); it is here recorded from Italy for the first time.