Chthonius caprai Gardini, 1977

Gardini, Giulio, 2021, The Italian species of the Chthonius ischnocheles group (Arachnida, Pseudoscorpiones, Chthoniidae), with reference to neighbouring countries, Zootaxa 4987 (1), pp. 1-131 : 19-22

Chthonius caprai Gardini, 1977

( Figs 49–59 , 411 )

Chthonius (Neochthonius) caprai Gardini, 1977: 216 , figs 1–7.

Chthonius (N.) caprai: Callaini 1979a: 129 .

Chthonius (C.) caprai: Gardini 1995: 44 .

Chthonius (Chthonius) leoi: Gardini 2011: 825 (Golfo Aranci, Chiaramonti, Villa Scema)

Type locality: Italy, Liguria, Genoa Province, Camogli, Monte di Portofino , Semaforo Nuovo (44°19’20”N, 9°09’09”E) .

Distribution. Italy (Liguria, Sicily and Sardinia).

Diagnosis (♂ ♀). An anophthalmic (rarely microphthalmic) epigean Chthonius that differs from other species of the ischnocheles group in the following combination of characters: anterior margin of carapace with 1 (rarely without) preocular microsetae; posterior margin of carapace with 6 (rarely 4) macrosetae; chelicerae with 1 or 2 lateral microsetae; chela length 0.31–0.43 mm; movable chelal finger length 0.21–0.28 mm; chelal fingers with contiguous teeth; movable chelal finger with coupled sensilla pc on a weak tubercle.

Type material examined. ITALY — Liguria: 1 ♂ 1 ♀ (holotype and paratype), Camogli, Monte di Portofino, Semaforo Nuovo , 2.II.1975, G. Gardini leg. ( MSNG) ; 6 ♀ (paratypes), id. ( MHNG, MNHN, NHMW) ; 1 ♂ 9 ♀ (paratypes), id. (G. Gardini coll., Genoa); 2 ♀ (paratypes), Ne, Pian di Fieno , 8. VIII .1976, G. Gardini leg. (G. Gardini coll., Genoa).

Other material examined. ITALY — Liguria: Genoa Prov. — 1 ♀, Genova, Villetta Di Negro , 1. V.1975, R. Poggi leg. , sieved under Quercus ilex ; 1 ♀, Ne, Monte Bossea , 20.IX.2018, M. Zinni & D. Badano leg. , under Buxus ; 2 ♀, San Colombano Certenoli, SE slope of Monte Ramaceto, 750 m a.s.l., 28. V.2010, L. Galli & G. Torrisi leg., under Pteridium ; 1 ♂ 1 ♀, Villagrande di Cichero , SE slope of Monte Mignano, 4. VI.2012, M. Capurro leg. Liguria: Imperia Prov. — 1 ♂, Diano San Pietro, Monte Colletto , 400 m a.s.l., 30. V.2007, T. Ardissone leg. , Quercus pubescens wood. Liguria: La Spezia Prov. — 1 ♀, Deiva Marina, 26.X.1972, R. Poggi leg. , Quercus suber wood; 5 ♂ 9 ♀, Vernazza, 25.II.2014, G. Lionetti leg., vineyard. Liguria: Savona Prov. — 1 ♂, Laigueglia, Colla Micheli, 132 m a.s.l., 13.I.2019, P. Gardini & C. Giusto leg. , under Quercus ilex . Sicily: Agrigento Prov. — 1 ♀, Isola Lampedusa, Cala Galera , 2.XII.1992, R. Poggi leg. ( MSNG) . Sicily: Ragusa Prov. — 1 ♂ 3 ♀, Cava d’Ispica, 3.IV.2010, G. Gardini leg., under Ceratonia . Sicily: Trapani Prov. — 6 ♀, Isola di Pantelleria, 7.X.1994, S. Ragusa di Chiara leg. , leaf litter; 5 ♀, id., 14.XII.1994, S. Ragusa di Chiara leg. , leaf litter; 1 ♂ 1 ♀, id., 20.II.2002, B. Massa leg. Sardinia: Cagliari Prov. — 1 ♀, Villacidro, Villa Scema , 20.IX.1986, P. Leo leg. Sardinia: Sassari Prov. — 1 ♀, Chiaramonti, 30.XII.1994, L. Fancello & P. Leo leg. ; 1 ♀, Golfo Aranci, 19.I.1994, L. Fancello & P. Leo leg.

Description of adults (♂ ♀). Integument slightly pigmented, carapace, tergites, chelicerae and pedipalps pale brown; weak hispid granulation on lateral surfaces of carapace, on cheliceral palm and on base of fixed chelal finger. Carapace ( Fig. 51 ) 0.95–1.0 times longer than broad, quadrate, weakly constricted posteriorly; anterior margin between median macrosetae with a prominent epistome, that has sharp denticles, mainly in females ( Figs 49–50 ); no eyes or eye-spots [rarely microphthalmic, according to Callaini (1979a)]; standard chaetotaxy m 4m:6:4:2:6(24), lateral macrosetae of posterior margin of carapace mainly shorter than medial ones; specimens from Sardinia (Chiaramonti, Golfo Aranci, Villa Scema) and Pantelleria Isl. without preocular microsetae; posterior margin of carapace rarely with five macrosetae ( Fig. 51 ), with four, five or six macrosetae in females from Pantelleria Isl. (see also Gardini 1995); length of anteromedian macrosetae 0.05–0.06 mm. Chaetotaxy of tergites 4:4:4:4:6:6:6:6:1T2T1:4:1T2T1:0. Chaetotaxy of sternites 8–11:(3)8–10(3):(2)6–8(2):8–9:6–7:6:6:6:2T1T2:0:2; genital opening of males flanked by 6 (rarely 5) setae on each side. Chelicerae ( Fig. 52 ) 1.95–2.0 (♂ ♀) times as long as broad, palm with 6 setae and 1 or 2 lateral microsetae; fixed finger with 8–11 teeth; movable finger with an isolated subapical tooth (di) located more proximal than the spinneret, and 7–8 teeth proximally reduced in size; gs ratio 0.55–0.62; spinneret prominent in both sexes ( Figs 52–53 ); rallum with 11 blades; serrulae interior and exterior with 10–12 and 12–14 blades respectively. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5–6, IV 6–7; coxa II with 3–7 coxal spines, coxa III with 1–5 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 3.8–4.1 (♂) or 3.4–4.0 (♀) times as long as broad, femoral chaetotaxy 3:5:2:5:1; chela ( Figs 56, 59 ) 4.4–4.7 (♂) or 4.1–4.6 (♀) times as long as deep; hand of chela 1.4–1.6 (♂ ♀) times as long as deep, ovoid in dorsal view ( Figs 54–55 ); fixed chelal finger with 42–53 contiguous teeth, tall and rectangular in the distal half of the finger, apically truncated and then rounded in the proximal half ( Figs 57–58 ); all teeth with dental canal; fixed finger at level of est-it with about 11 teeth occupying 0.05 mm; tip of fixed chelal finger with apical sensilla af 1- 2, distal paraxial seta gradually curved and thin; movable chelal finger with 37–47 contiguous teeth, similar to those of fixed chelal finger, apically rounded from sb towards finger base ( Figs 56–59 ); movable finger at level of st-t with about 11 teeth occupying 0.05 mm; coupled sensilla pc mainly just distad of sb and on a weak tubercle; tip of movable chelal finger with apical sensilla am 1- 2; trichobothria as in figs 56, 59; trichobothrium sb halfway between b and st or just closer to b; ratio of movable finger/hand of chela 1.75–2.1 (♂ ♀); ratio of pedipalpal femur/movable finger 0.9–1.0 (♂ ♀); ratio of pedipalpal femur/carapace 0.8–1.0 (♂ ♀).

Measurements (in mm). Body length 0.6–0.7 (♂) or 0.75–0.95 (♀). Carapace 0.22–0.24 × 0.22–0.24 (♂) or 0.26–0.28 × 0.26–0.29 (♀). Chelicerae 0.18–0.20 × 0.09–0.10 (♂) or 0.215–0.25 × 0.105–0.12 (♀); movable finger length 0.09–0.105 (♂) or 0.105–0.13 (♀). Pedipalp: femur 0.19–0.20 × 0.05 (♂) or 0.21–0.275 × 0.06–0.075 (♀); chela 0.31–0.35 × 0.07 (♂) or 0.34–0.43 × 0.08–0.10 (♀); hand length 0.10–0.11 (♂) or 0.12–0.16 (♀); movable finger length 0.21–0.225 (♂) or 0.23–0.28 (♀).

Remarks. Among the species of the Chthonius ischnocheles group, C. caprai is morphologically similar to the epigean C. jonicus Beier, 1931 also known from central and southern Italy, Sicily and Sardinia, and to C. leoi ( Callaini, 1988) from Sardinia.

Chthonius caprai differs from C. jonicus in the following characters: posterior margin of carapace mainly with 6 macrosetae (with 4 macrosetae in C. jonicus ); no eyes (anterior eyes with flat lens, posterior ones reduced to a pale cuticular area in C. jonicus ); chelicerae with 1 or 2 lateral microsetae (without lateral microsetae in C. jonicus ); chela length 0.31–0.43 mm (0.40–0.51 mm in C. jonicus ); movable chelal finger length 0.21–0.28 mm (0.275–0.34 mm in C. jonicus ); movable chelal finger with coupled sensilla pc on a weak tubercle (coupled sensilla pc not on a tubercle in C. jonicus ).

Chthonius caprai differs from C. leoi in the following characters: anterior margin of carapace mainly with 1 preocular microseta on each side (without preocular microsetae in C. leoi ); posterior margin of carapace mainly with 6 macrosetae (with 4 macrosetae in C. leoi ).

The disjointed distribution of Chthonius caprai ( Fig. 411 ), not recorded so far from central and southern Italy, may be caused by a lack of sampling and difficulties imposed by the small size of the species. Ligurian specimens show stability in carapacal chaetotaxy (anterior margin with 1 preocular microseta on each side, posterior margin with 6, rarely 5, macrosetae) while specimens from Pantelleria Isl. and Sardinia lack preocular microsetae, and specimens from Pantelleria Isl. have the posterior margin of carapace with 4 to 6 macrosetae. Moreover, part of the specimens from the Aeolian Archipelago are microphthalmic ( Callaini 1979a).

Variability of the main characters used to distinguish Chthonius leoi from C. caprai may suggest a probable synonymy of the two species, which however is not formally proposed here due to the scarcity of the Sardinian specimens available for examination.

The above description of Chthonius caprai incorporates the data provided by Gardini (1977).

Figures

FIGURES 49–55. Chthonius caprai Gardini, 1977, Vernazza (La Spezia). 49, male, anterior margin of carapace; 50, female, id.; 51, male, carapace; 52, male, right chelicera; 53, female, movable finger of right chelicera; 54, male, right chelal hand, dorsal view; 55, female, id.

FIGURES 56–59. Chthonius caprai Gardini, 1977, Vernazza (La Spezia). 56, male, right chela, antiaxial view; 57, male, detail of fingers at the distal half of right chela, antiaxial view; 58, male, detail of fingers at level of trichobothrium sb, antiaxial view; 59, female, right chela, antiaxial view.

FIGURES 410–413. Distribution maps for the Italian species of the Chthonius ischnocheles group. 410, Chthonius caoduroi Callaini, 1987, Chthonius gallettii n. sp., Chthonius inguscioi n. sp., Chthonius marciai n. sp. and Chthonius multidentatus Beier, 1963; 411, Chthonius caprai Gardini, 1977, Chthonius jonicus Beier, 1931 and Chthonius leoi (Callaini, 1988); 412, Chthonius halberti Kew, 1916, Chthonius nicolosii n. sp., Chthonius ressli Beier, 1956 and Chthonius stammeri Beier, 1942; 413, Chthonius horridus Beier, 1934, Chthonius italicus Beier, 1930 and Chthonius lanai n. sp.