Chthonius
Creators: name: Gardini, Giulio
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Chthonius

description: [Chthonius (E.) gibbus Beier, 1953]
(Figs 94–97)
Chthonius (Ephippiochthonius) gibbus Beier 1953a: 293, fig. 1.
Not Chthonius (E.) gibbus: Mahnert 1975: 186, figs 1a, 1c (misidentification, see C. siculus); Mahnert 1975: 186, fig. 1b (misidentification, see C. berninii); Callaini 1979a: 134, figs IIa, b (misidentification, see C. siculus); Callaini 1983b: 403 (misidentification, see C. siculus); Callaini 1989: 138 (misidentification, see C. siculus); Gardini 1995a: 3 (misidentification, see C. siculus); Gardini 1995b: 45 (misidentification, see C. siculus); Gardini et al. 1997: 221 (misidentification, in part, see C. nanus and C. siculus); Gardini 2008b: 631 (misidentification, see C. siculus).
Chthonius (E.) cfr. gibbus: Gardini 1980c: 268, figs 16–22 (misidentification, see C. tyrrhenicus); Callaini 1986: 345, fig. Ic (misidentification, see C. siculus).
Type locality: Spain, Madrid Comun., El Escorial (40°35ʹ21ʺN 4°08ʹ53ʺW).
Distribution. Mainland Spain. Identifications from Algeria, Canary Islands, France (mainland and Corsica), Italy (mainland, Sardinia and Sicily), Malta, Morocco, mainland Portugal and Spain (Balearic Islands) (Beier 1975; Harvey 1991, 2011) are doubtful and need to be confirmed.
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 with isolated subapical tooth (di); carapace without epistome and without preocular microsetae; posterior margin of carapace with 2 macrosetae; hand of chela depressed at level of ib-isb and with an evident hump distad of ib-isb; pedipalpal fixed finger with 14 triangular teeth, at level of est-it with 5 teeth occupying 0.1 mm (distance between successive apices 0.020 mm); length of chela 0.63 mm, length of movable chelal finger 0.37 mm; chela 4.5 times as long as deep; ratio of pedipalpal femur/carapace 1.2.
Type material examined. SPAIN — Madrid— 2 Ƥ, “ Chthonius (E.) gibbus n. sp. / Typen. Beier” “ Spanien, Escorial / 15.2.1951. Franz leg.” (NMW).
Description of adult (Ƥ). Integument decolourized by alcohol; weakly hispid granulation on lateral surfaces of carapace. Carapace as long as broad (1.0), subquadrate; anterior margin (fig. 94) with sharp denticles between median macrosetae; anterior margin weakly prominent in one female; ocular area as in fig. 95, anterior eyes with convex lens, posterior ones reduced, with flat lens; chaetotaxy 4:6:4:2:2 (18), preocular microsetae absent. Chaetotaxy tergites I–X 4:4:4:4:6:6:6:6:6:4. Chaetotaxy sternites II–X 8:(3)7(3):(2)7(2):7:6:6:6:6:7. Chelicerae (fig. 96) 2.1 times as long as broad, palm with 6 setae and 1 microseta laterally; fixed finger with 6–7 teeth proximally reduced in size and few proximal microtubercles; movable finger with a large isolated tooth (di), at level with the spinneret, and with 6 teeth (the distal one larger and apically bicuspid); gl ratio 0.56; spinneret prominent and apically rounded; 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 7–8 coxal spines, coxa III with 4–6 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 5.3 times as long as broad; chela (fig. 97) 4.5 times as long as deep; hand of chela1.9 times as long as deep, depressed at level of ib-isb and with an evident and deep hump distad of ibisb; fixed chelal finger with 16 teeth: one distal tooth very small, 14 triangular, weakly reclined, large teeth with dental canals, proximally reduced in size, and one proximal tooth apically rounded; base of fixed finger with 2 microtubercles; tip of fixed finger with a modified accessory tooth (td) on antiaxial face; pedipalpal fixed finger at level of est-it with 5 teeth occupying 0.1 mm (distance between successive apices 0.020 mm); movable chelal finger with 10 triangular teeth, the three proximal ones smaller, the others larger, upright, all with dental canals; proximal third of movable chelal finger with 4–5 vestigial teeth, widely rounded; coupled sensilla pc sensilla nearer to sb than to b; trichobothria as in fig. 97, eb-esb-ist placed in a straight line; basal apodeme of movable finger strongly sclerotized, rectangular, squat; ratio of movable finger/hand of chela 1.4; ratio of pedipalpal femur/ movable finger 1.2; ratio of pedipalpal femur/carapace 1.2.
Measurements (in mm). Body length 1.6. Carapace 0.37 × 0.36 (0.33 anteriorly). Chelicerae 0.30 × 0.145; movable finger length 0.16. Pedipalp: femur 0.45 × 0.085; chela 0.63 × 0.14; hand length 0.265; movable finger length 0.37.
Remarks. The epigean species Chthonius gibbus was described by Beier (1953), based on two females from mainland Spain (Madrid: El Escorial), and it has since been recorded from many localities of the Iberian Peninsula (Zaragoza 2007), from all the countries that surround the central-western Mediterranean (Harvey 1991, 2011) and from the Canary Islands (Beier 1975). Gardini (2000) cites all Italian records of C. gibbus for Liguria, Calabria, Sicily and Sardinia. All of the previous records have been based on the original description of Beier (1953), repeated in Beier (1963a).
Examination of the syntypes of C. gibbus reveals the presence of an isolated subapical tooth (di) on the movable cheliceral finger, which proves that all Italian records of C. gibbus are due to misidentifications. It is not possible to refer the specimens from Corsica recorded by Callaini (1981) to any existing Ephippiochthonius species. Other records concerning Mediterranean countries need to be checked.
description: Published as part of Gardini, Giulio, 2013, A revision of the species of the pseudoscorpion subgenus Chthonius (Ephippiochthonius) (Arachnida, Pseudoscorpiones, Chthoniidae) from Italy and neighbouring areas, pp. 1-151 in Zootaxa 3655 (1) on pages 52-53, DOI: 10.11646/zootaxa.3655.1.1, http://zenodo.org/record/223358