Chthonius etruscus, Gardini, Giulio, 2013

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 : 37-40

Chthonius (E.) etruscus n. sp.

( Figs 59–67 , 292 )

Type locality: Italy, Tuscany, Grosseto Prov., Semproniano, Grotta di Montecchio 254 To/GR (42°42ʹ20ʺN 11°30ʹ28ʺE).

Distribution. Italy: Tuscany.

Diagnosis (Ƥ). An anophthalmic hypogean Chthonius (Ephippiochthonius) from Tuscany that differs from other species of the C. fuscimanus group in the following combination of characters: movable cheliceral finger with isolated subapical tooth (di); carapace without epistome, with 2 preocular microsetae on each side; pedipalpal hand (in lateral view) weakly depressed at level of ib-isb; fixed and movable chelal finger respectively with 11–15 and 6–8 triangular teeth; pedipalpal fixed finger at level of est-it with 3–4 teeth occupying 0.1 mm (distance between apices 0.030–0.041 mm); proximal half of movable chelal finger with straight, thick marginal lamina; length of chela 0.81 (3), 0.83–0.90 (Ƥ) mm, length of movable chelal finger 0.48 (3), 0.48–0.53 (Ƥ) mm; chela 6.75 (3), 5.3–6.4 (Ƥ) times as long as deep; ratio of pedipalpal femur/carapace 1.4–1.5 (3Ƥ).

Type material. ITALY — Tuscany: Grosseto Prov.— 1 Ƥ (holotype) 4 Ƥ (paratypes), Semproniano, Grotta di Montecchio 254 To/GR (42°42ʹ20ʺN 11°30ʹ28ʺE), 320 m a.s.l., 9.IX.1990, L. Latella & S. Zoia leg.; 1 3 (paratype), Grosseto, Monti dell’Uccellina, Pozzo del Granduca 595 To/GR, 120 m a.s.l., 26.IV.1990, S. Vanni & S. Taiti leg.; 1 Ƥ (paratype), Grosseto, Monti dell’Uccellina, Pozzo del Granduca 595 To/GR, 120 m a.s.l., 13.V.1990, S. Zoia leg. (holotype deposited in MNHG, paratypes in G. Gardini coll., Genoa).

Derivatio nominis. The Etruscans were the ancient people inhabiting Etruria, a region of central Italy comprising the present Tuscany, Umbria and part of Latium.

Description of adults (Ƥ). Integument with weak pigmentation; hispid granulation on lateral surface of carapace, on cheliceral palm and on ventral surface of pedipalpal hand. Carapace 1.0 3Ƥ times longer than broad, posteriorly slightly constricted; anterior margin (figs 59–60) strongly dentate between median macrosetae, without epistome; ocular area as in figs 61–62, no eyes or eye-spots; chaetotaxy mm 4mm:6:4:2:2(18), macrosetae weakly thick; length of anteromedian macrosetae 0.085–0.11 mm. Chaetotaxy of tergites I–X 4:4:4:4:6:6:6:6:6:4. Chaetotaxy of sternites II–X 10:(3)7 or 8(3):(2)7(2):8:6:6:6:6:7; sternite II exceptionally with 9 or 11 setae, st. IV exceptionally with 6 or 8 setae. Chelicerae (figs 63–64) 2.1–2.2 times as long as broad, palm with 6 setae and 2 microsetae laterally; fixed finger with 6–8 teeth proximally reduced in size and 5–6 proximal microtubercles; movable finger with a subapical tooth (di) level with the spinneret in male, proximad of spinneret in female, 5–6 teeth proximally reduced in size and 4–6 proximal microtubercles; gl ratio 0.52–0.62; spinneret weakly prominent in male, prominent and apically rounded in females; 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 (rarely 3), III 5, IV 6; coxa II with 8–11 coxal spines, coxa III with 3–6 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 6.4 (3), 5.9–6.5 (Ƥ) times as long as broad; chela (figs 65–67) 6.75 (3), 5.3–6.4 (Ƥ) times as long as deep; hand of chela 2.65 (3), 2.2–2.6 (Ƥ) times as long as deep, depressed proximad or at level of trichobothria ib-isb; fixed chelal finger with 11–15 teeth with dental canals: the first 1–3 proximal teeth with tip rounded, the others 10–13 teeth triangular, upright; base of fixed finger with 2–10 microtubercles; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; fixed chelal finger at level of est-it with 3–4 teeth occupying 0.1 mm (distance between successive apices 0.030–0.041 mm); distal half of movable chelal finger with 6–8 triangular, upright teeth with dental canals, the first proximal tooth pointed or rounded; proximal half of movable finger with thick marginal lamina, weakly undulated, becoming thinner between sb and b; coupled sensilla pc halfway between sb and b, or nearer sb than b; trichobothria as in figs 66–67, eb-esb-ist placed in a straight line or with ist a little distad of the line eb-esb; basal apodeme of movable finger strongly sclerotized, rectangular; ratio of movable finger/hand of chela 1.4–1.5 (3Ƥ); ratio of pedipalpal femur/movable finger 1.2 (3Ƥ); ratio of pedipalpal femur/carapace 1.4–1.5 (3Ƥ).

Measurements (in mm). Body length 1.4 (3), 1.5–1.65 (Ƥ). Carapace 0.41 × 0.38 (0.35 anteriorly) (3), 0.41– 0.44 × 0.40–0.43 (0.37–0.40 anteriorly) (Ƥ). Chelicerae 0.34 × 0.15 (3), 0.36–0.40 × 0.165–0.175 (Ƥ), movable finger length 0.175 (3), 0.18–0.20 (Ƥ). Pedipalp: femur 0.58 × 0.09 (3), 0.59–0.65 × 0.10 (Ƥ); chela 0.81 × 0.12 (3), 0.83–0.90 × 0.14–0.16 (Ƥ); hand length 0.32 (3), 0.35–0.36 (Ƥ); movable chelal finger length 0.48 (3), 0.48– 0.53 (Ƥ).

Remarks. Among the species of the Chthonius fuscimanus group, C. etruscus n. sp. is related to the epigean C. nanus and C. tyrrhenicus —both common and widespread species in the same geographical area—from which it differs in many troglomorphic characters.

C. etruscus differs from other hypogean species of central Italy ( C. sulphureus , C. latellai ) in a lower degree of troglomorphy: smaller size and less elongated appendages [length of chela 0.81 (3) 0.83–0.90 (Ƥ) mm, chela 6.75 (3) 5.3–6.4 (Ƥ) times as long as deep, ratio of pedipalpal femur/carapace 1.4–1.5 in C. etruscus ; length of chela 1.07–1.19 (3) 1.11–1.27 (Ƥ) mm, chela 7.2–8.4 (3) 6.6–7.9 (Ƥ) times as long as deep, ratio of pedipalpal femur/ carapace 1.7–1.9 in C. sulphureus and C. latellai ] and in the shape of the chelal hand: rather squat, in lateral view, with square profile in C. etruscus , elongated in C. sulphureus and C. latellai . C. etruscus differs from the hypogean C. magrinii in the presence of preocular microsetae, the absence of an epistome and the shape of the chelal hand.

Figures

FIGURES 59 – 65. Chthonius (E.) etruscus n. sp. 59, male paratype (Tuscany, Pozzo del Granduca), anterior margin of carapace; 60, female holotype, id.; 61, male paratype (Tuscany, Pozzo del Granduca), anterolateral portion of carapace; 62, female holotype, id.; 63, male paratype (Tuscany, Pozzo del Granduca), right chelicera; 64, female holotype, fingers of right chelicera; 65, male paratype (Tuscany, Pozzo del Granduca), tip of fixed chelal finger, dorsal view.

FIGURES 66 – 67. Chthonius (E.) etruscus n. sp. 66, male paratype (Tuscany, Pozzo del Granduca), right chela, lateral view; 67, female holotype, id. (Scale bar 0.1 mm).

FIGURES 290 – 293. Distribution maps for the Italian species of the Chthonius fuscimanus group. 290, Chthonius (E.) boldorii Beier, 1934; 291, Chthonius (E.) genuensis Gardini, 1990, C. (E.) gestroi Simon, 1896, C. (E.) monguzzii n. sp., C. (E.) pieltaini Beier, 1930, C. (E.) troglophilus Beier, 1930 and C. (E.) zoiai Gardini, 1990; 292, Chthonius (E.) etruscus n. sp., C. (E.) latellai n. sp., C. (E.) magrinii n. sp. and C. (E.) sulphureus n. sp.; 293, Chthonius (E.) aeneae n. sp., C. (E.) gallii n. sp., C. (E.) intemelius n. sp. and C. (E.) ligur n. sp.