Chthonius sulphureus, 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 : 110-112

Chthonius (E.) sulphureus n. sp.

( Figs 210–218 , 292 )

Type locality: Italy, Marche, Ancona Prov., Genga, Grotta di Frasassi 1 Ma/AN (43°24ʹ0 7ʺN 12°58ʹ0 7ʺE).

Distribution. Italy: Marche.

Diagnosis (Ƥ). An anophthalmic hypogean Chthonius (Ephippiochthonius) from Marche that differs from other species of the C. fuscimanus group in the following combination of characters: movable cheliceral finger with isolated subapical tooth (di) proximal with respect to the spinneret; carapace without epistome, with 2 preocular microsetae on each side; chelal hand (in lateral view) without a rounded hump distad of trichobothria ib-isb; fixed and movable chelal finger respectively with 14 and 8 triangular teeth; fixed chelal finger at level of est-it with 3 teeth occupying 0.1 mm (distance between successive apices 0.035–0.040 mm); proximal half of movable chelal finger with straight, thick marginal lamina; length of chela 1.07–1.095 (3), 1.11–1.25 (Ƥ) mm, length of movable chelal finger 0.64–0.66 (3), 0.65–0.73 (Ƥ) mm; chela 7.2–7.4 (3), 6.6–6.9 (Ƥ) times as long as deep; ratio of pedipalpal femur/carapace 1.7–1.8 (3Ƥ).

Type material. ITALY— Marche: Ancona Prov.— 1 3 (holotype) 1 3 6 Ƥ (paratypes), Genga, Grotta di Frasassi 1 Ma/AN (43°24ʹ0 7ʺN 12°58ʹ0 7ʺE), 15.XI.1996, S. Sarbu leg., deep section; 2 3 4 Ƥ (paratypes), Genga, Grotta di Frasassi 1 Ma/AN, Grotta del Fiume-Grotta del Vento, Ramo sulfureo, 7.IX.1998, S. Sarbu leg.; 2 Ƥ (paratypes), Genga, Grotta di Frasassi 1 Ma/AN, Grotta Sulfurea, 7.IX.1998, S. Sarbu leg. (holotype deposited in MHNG, paratypes in G. Gardini coll., Genoa).

Derivatio nominis. Sulphureus (Latin, adj.), relating to sulphur. The deep zones of the Frasassi caves complex are characterized by the presence of hydrogen sulphide and the organic material is produced by chemoautotrophic organisms (Sarbu et al. 2000), allowing the development and maintenance of a hypogean community, including C. sulphureus .

Description of adults (Ƥ). Troglomorphic facies. Integument weakly pigmented; marked hispid granulation on lateral surfaces of carapace, on cheliceral palm and on ventrodistal surface of chelal hand. Carapace 1.0 times longer than broad, posteriorly constricted; anterior margin (figs 210–211) closely denticulate between median macrosetae, without epistome; ocular area as in fig. 212, no eyes or eye-spots; chaetotaxy mm 4mm:6:4:2:2(18), macrosetae fine; length of anteromedian macrosetae 0.12–0.13 mm. Chaetotaxy of tergites I–X 4:4:4:4:6:6:6:6:6:4.

Chaetotaxy of sternites II–X 10:(3)8(3):(2)7(2):8:6:6:6:6:7; sternite III rarely with (3)7(3) setae, sternite V rarely with 9 setae; genital opening of males flanked by 7–8 (rarely 6) setae on each side. Chelicerae (figs 213–215) 2.3– 2.45 times as long as broad, palm with 6 setae and 2 microsetae laterally; fixed finger with 9–12 teeth, proximally reduced in size, and 4–7 proximal microtubercles; movable finger with an isolated subapical tooth (di), proximal with respect to the spinneret, 5–8 teeth, distal tooth prominent and apically indented, and 3–5 proximal microtubercles; gl ratio 0.57–0.62; spinneret weakly prominent in males, prominent, acute and apically rounded in females; rallum with 11 blades. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5, IV 6; coxa II with 11–16 coxal spines, coxa III with 5–9 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 7.4–7.7 (3), 7.2–7.65 (Ƥ) times as long as broad; chela (figs 216–218) 7.2–7.4 (3), 6.6– 6.9 (Ƥ) times as long as deep; hand of chela 2.9–3.0 (3), 2.7–2.8 (Ƥ) times as long as deep, weakly depressed behind trichobothria ib-isb; fixed chelal finger with 14 large, triangular, pointed teeth, one proximal tooth with rounded tip, all with dental canals and 3–5 microtubercles at finger base; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; fixed chelal finger at level of est-it with 3 teeth occupying 0.1 mm (distance between successive apices 0.035–0.040 mm); distal half of movable chelal finger with 8 large, triangular, upright and pointed teeth and 1 proximal rounded tooth, all with dental canals; proximal half of movable chelal finger with straight, thick marginal lamina (rarely irregular and thinner) between b and sb; coupled sensilla pc nearer to sb than to b; trichobothria as in figs 217–218; basal apodeme of movable chelal finger strongly sclerotized, long, narrowed and indented apically; trichobothria eb-esb-ist placed in a straight line; ratio of movable finger/hand of chela 1.5 (3), 1.4 (Ƥ); ratio of pedipalpal femur/movable finger 1.2 (3Ƥ); ratio of pedipalpal femur/carapace 1.7–1.8 (3Ƥ).

Measurements (in mm). Body length 1.7–1.8 (3), 1.7–2.0 (Ƥ). Carapace 0.44–0.45 × 0.43–0.45 (0.39–0.42 anteriorly) (3), 0.47–0.53 × 0.47–0.52 (0.44–0.49 anteriorly) (Ƥ). Chelicerae 0.41–0.42 × 0.17–0.175 (3), 0.445– 0.49 × 0.18–0.20 (Ƥ), movable finger length 0.21 (3), 0.21–0.25 (Ƥ). Pedipalp: femur 0.76–0.78 × 0.10–0.105 (3), 0.80–0.88 × 0.11–0.12 (Ƥ); chela 1.07–1.095 × 0.145–0.15 (3), 1.11–1.25 × 0.16–0.185 (Ƥ); hand length 0.43– 0.44 (3), 0.45–0.51 (Ƥ); movable finger length 0.64–0.66 (3), 0.65–0.73 (Ƥ).

Remarks. Among the species of the Chthonius fuscimanus group, C. sulphureus n. sp. is probably related to the epigean C. tyrrhenicus from the same geographical area, from which it differs in most troglomorphic characters, and to C. etruscus and C. latellai , hypogean species from central Italy. For comparisons between C. sulphureus , C. etruscus and C. latellai see Remarks under the latter two species.

C. sulphureus , like C. latellai , inhabits a karstic complex characterized by the presence of hydrogen sulphide (Sarbu et al. 2000, Latella et al. 1999).

Figures

FIGURES 210 – 216. Chthonius (E.) sulphureus n. sp. (Marche, Genga, Grotta di Frasassi). 210, male holotype, anterior margin of carapace; 211, female paratype, id.; 212, male holotype, anterolateral portion of carapace; 213, id., right chelicera; 214, male paratype, fingers of left chelicera; 215, female paratype, fingers of right chelicera; 216, male holotype, tip of fixed chelal finger, dorsal view.

FIGURES 217 – 218. Chthonius (E.) sulphureus n. sp. (Marche, Genga, Grotta di Frasassi). 217, male holotype, right chela, lateral view; 218, female paratype, 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.