Chthonius messapicus, 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 : 74-76

Chthonius (E.) messapicus n. sp.

( Figs 151–154 , 285 )

Type locality: Italy, Apulia, Brindisi Prov., San Pietro Vernotico, Cerano (40°32ʹ53ʺN 18°02ʹ0 3ʺE).

Distribution. Italy: Apulia.

Diagnosis (3). An eyed epigean Chthonius (Ephippiochthonius) from Apulia that differs from other species of the C. tetrachelatus group in the following combination of characters: movable cheliceral finger with isolated subapical tooth (di), males without spinneret; carapace without epistome, with 2 preocular microsetae on each side; posterior margin of carapace with 2 macrosetae and 1–2 lateral microsetae on each side; length of anteromedian macrosetae of carapace 0.066–0.070 mm; pedipalpal fixed finger at level of est-it with 5 teeth occupying 0.1 mm (distance between successive apices 0.025–0.026 mm); movable chelal finger with 8–9 teeth; length of chela 0.60– 0.62 mm, length of movable chelal finger 0.35–0.37 mm.

Type material. ITALY— Apulia: Brindisi Prov.— 1 3 (holotype) 2 3 (paratypes) ( C. tetrachelatus, M. Beier det.), San Pietro Vernotico, Cerano (40°32ʹ53ʺN 18°02ʹ0 3ʺE), 7.IX.1973, G. Gardini leg., sieved in Quercus ilex wood (holotype deposited in MHNG, paratypes in G. Gardini coll., Genoa).

Derivatio nominis. The Messapii were an ancient Italian population, of probable Illyrian origin, who settled in Apulia in the southern Murge and in Salento; the present San Pietro Vernotico is located in the Messapian Plains.

Description (3; Ƥ unknown). Integument with weak pigmentation, carapace, tergites, chelicerae and pedipalps yellow-brown; marked hispid granulation on lateral surface of carapace, on cheliceral palm and on base of movable chelal finger. Carapace 1.0 times longer than broad, quadrate; anterior margin (fig. 151) dentate between median macrosetae, without epistome (anterior margin weakly prominent in one paratype 3); ocular area as in fig. 152, anterior eyes with convex lens (diameter 0.04 mm), posterior eyes with flat lens, all eyes with tapetum; distance from anterior eyes to anterior margin of carapace 0.03 mm; chaetotaxy mm 4mm:6:4:2:mm 2mm (18), macrosetae thick and short; posterior margin of carapace with one microseta on each side in a paratype 3; length of anteromedian macrosetae 0.066–0.070 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; genital opening of males flanked by 6–8 setae on each side. Chelicerae (fig. 153) 2.1 times as long as broad, palm with 6 setae and 3–4 microsetae laterally; fixed finger with 5–6 teeth proximally reduced in size and 4–6 proximal microtubercles; movable finger with a large isolated subapical tooth (di), with 5–6 teeth proximally reduced in size (the distal two prominent) and 1–2 proximal microtubercles; gl ratio 0.54–0.55; males without spinneret; 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 8–10 coxal spines, coxa III with 4–6 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 5.4 times as long as broad; chela (fig. 154) 5.1–5.45 times as long as deep; hand of chela 2.1–2.2 times as long as deep, weakly depressed at level of ib-isb; fixed chelal finger with 17–18 teeth: 13–16 triangular, weakly reclined and 2–4 proximal rounded teeth, all with dental canals; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; fixed chelal finger at level of est-it with 5 teeth occupying 0.1 mm (distance between successive apices 0.025–0.026 mm); movable chelal finger with 8–9 triangular, upright teeth with dental canals; proximal third of movable finger with 3–4 vestigial rounded teeth; coupled sensilla pc at level of sb or halfway between b and sb; trichobothria as in fig. 154, eb-esb-ist placed in a straight line; basal apodeme of movable finger strongly sclerotized, squat, apically truncated; ratio of movable finger/hand of chela 1.4–1.5; ratio of pedipalpal femur/movable finger 1.2; ratio of pedipalpal femur/carapace 1.2.

Measurements (in mm). Body length 1.2–1.3. Carapace 0.34–0.36 × 0.34–0.36 (0.30–0.31 anteriorly). Chelicerae 0.27–0.28 × 0.125–0.135; movable finger length 0.14. Pedipalp: femur 0.43 × 0.08; chela 0.60–0.62 × 0.11–0.12; hand length 0.245–0.25; movable finger length 0.35–0.37.

Remarks. Among the species of the Chthonius tetrachelatus group, C. messapicus n. sp. is related to the epigean C. lucanus from central and southern Italy because of the presence of an isolated subapical tooth (di) on the movable cheliceral finger. For a comparison of these two species, see Remarks under C. lucanus .

Figures

FIGURES 151 – 154. Chthonius (E.) messapicus n. sp., male holotype. 151, anterior margin of carapace; 152, anterolateral portion of carapace; 153, right chelicera; 154, right chela, lateral view.

FIGURES 282 – 285. Distribution maps for the Italian species of the Chthonius tetrachelatus group. 282, Chthonius (E.) tetrachelatus (Preyssler, 1790); 283, Chthonius (E.) siculus Beier, 1961 and C. (E.) vachoni Heurtault-Rossi, 1963; 284, Chthonius (E.) concii Beier, 1953 and C. (E.) lucanus Callaini, 1984; 285, Chthonius (E.) altamurae n. sp., C. (E.) apulicus Beier, 1958, C. (E.) elymus n. sp., C. (E.) grafittii Gardini, 1981, C. (E.) messapicus n. sp., C. (E.) poseidonis Gardini, 1993 and C. (E.) sardous Gardini, 2008.