Chthonius
Creators: name: Zaragoza, Juan A.
name: Pérez, Toni
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Chthonius

description: Chthonius (E.) tetrachelatus (Preyssler, 1790)
Material. Spain, Andalusia, Jaén province, Villacarrillo, Cueva de la Fuente del Tejo (38º3′24.32″N, 2º54′27.96″W; 1490 m.a.s.l.), 22.VII.2008, lgt. G.E.V., 4 ♂, 1 ♀, 1 T (DEUA).
Description. Epigean species, integument pigmented, without troglomorphic adaptations.
Carapace subquadrate, slightly longer than broad; anterior margin medially denticulate and weakly prominent; four eyes with lens and reflective tapeta, anterior eyes with convex lens, posterior eyes with weak lens; diameter of anterior eyes 0.045–0.05 mm, distance from anterior eyes to anterior margin of carapace 0.03–0.035 mm, distance from anterior to posterior eyes 0.04–0.045 mm; chaetotaxy: 18–19 macrosetae, formula: m 4m:6:4:2: 2 in males, 4:6:4:2: 3 in female, anteromedial seta 0.11 mm long, ocular seta 0.08 mm; Four or five lyrifissures in the anterior and ocular areas, two in the posterior area.
Pedipalpal coxa with 5 setae (including 2 on manducatory process), coxa I 3 + 3 marginal microsetae, II 4 + 8– 9 bipinnate coxal spines, III 5 + 4 bipinnate coxal spines and IV 6; intercoxal tubercle bisetose.
Chaetotaxy of tergites I–XI: 4:4:4:4:6:6:6:6:6:4:1T2T1. Genital area with 10 setae on sternite II in male and female; sternite III with (3)8(3) setae in females; sternite III in males with genital opening flanked by 6–8 setae on each side, 4+4 internal glandular setae and (3)10(3) marginal setae. Chaetotaxy of sternites IV–XI: (2)7(2):7:6:6:6:6:7:0. Anal cone 0+2 setae.
Chelicera with 6 setae on palm and 1 microseta laterally; seta gl 0.58–0.61 from base of movable finger. Fixed finger with 10–11 teeth, proximally decreasing in size. Movable finger without an isolated subapical tooth (di), a large, single or bicuspid distal tooth and 5–6 teeth reduced in size proximally; spinneret low prominent and apically rounded, markedly more developed in female. Rallum with 11 blades, serrulae exterior and interior with 14 and 13 blades respectively.
Pedipalp with femoral chaetotaxy: 3:6:2:5:1, four lyrifissures: one antiaxial and three paraxial. Chelal hand very weakly depressed at level of ib-isb, weak hump distad of ib-isb. Fixed finger with 18–20 pointed teeth, one or two distal ones small, 5–6 basal teeth progressively decreasing in size, all with dental canals, 3–4 microtubercles at base; tip of finger with an accessory tooth (td) on antiaxial face; four teeth at level of est/it occupying 0.1 mm, distance between apices 0.033 mm. Distal half of movable finger with 7–8 pointed teeth with dental canals, the distal one small; proximal half without marginal lamina, with 7 low vestigial teeth reaching trichobothrium sb, with dental canal; coupled sensilla pc between sb and b, slightly closer to sb; basal apodeme long and apically indented. Trichobothrium ist level with esb.
Leg IV. Tactile seta ratios: tibia 0.58–0.6, basitarsus 0.37–0.4 and tarsus 0.32.
Measurements and ratios. Male. Body 1.82. Carapace 0.47/0.46 (1.0). Chelicera: palm 0.40/0.19 (2.2), movable finger 0.21. Pedipalp: femur 0.69/0.11 (6.5); patella 0.25/0.13 (2.0); chela 0.95/0.17 (5.5), depth 0.18 (5.2); hand 0.38 (2.2), length/depth (2.1); movable finger 0.58; ratio movable finger/hand 1.5; ratio femur/movable finger 1.2; ratio femur/carapace 1.5; ratio chela/carapace 2.0. Leg I: femur 0.41/0.07 (5.7); patella 0.20/0.07 (3.1); tibia 0.24/0.05 (4.7); tarsus 0.40/0.04 (9.4); ratio femur/patella 2.1. Leg IV: femur+patella 0.60/0.24 (2.6); tibia 0.40/0.09 (4.7); basitarsus 0.23/0.07 (3.5); telotarsus 0.42/0.04 (11.3); ratio telotarsus/basitarsus 1.8.
Female. Body 1.83. Carapace 0.51/0.5 (1.0). Chelicera: palm 0.44/0.21 (2.1), movable finger 0.22. Pedipalp: femur 0.73/0.13 (5.8); patella 0.30/0.15 (2.0); chela 1.02/0.21 (4.7), depth 0.22 (4.5); hand 0.43 (2.0), length/depth (1.9); movable finger 0.59; ratio movable finger/hand 1.4; ratio femur/movable finger 1.2; ratio femur/carapace 1.4; ratio chela/carapace 2.0. Leg I: femur 0.44/0.08 (5.5); patella 0.21/0.07 (3.0); tibia 0.25/0.05 (4.9); tarsus 0.45/ 0.05 (9.9); ratio femur/patella 2.1. Leg IV: femur+patella 0.65/0.26 (2.5); tibia 0.41/0.09 (4.6); basitarsus 0.23/0.07 (3.3); telotarsus 0.44/0.04 (11.0); ratio telotarsus/basitarsus 1.9.
Distribution. Western Palaearctic Region, chiefly Mediterranean; introduced to eastern Canada, U.S.A. (including Hawaii), Cuba, Argentina, Seychelles and southwestern Australia (Gardini 2013; Harvey 2011). New record for the province of Jaén, the second after Málaga for the Andalusian region; detailed locations for the Iberian Peninsula are given in Zaragoza (2007).
Remarks. These specimens fall within the wide range of variation described for C. (E.) tetrachelatus by Gardini (2009, 2013). Some chelal measures lie at the extremes of the ranges or exceed them (e.g. ratio movable finger/hand). We agree with Gardini (2013) that “the heterogeneous morphology of C. tetrachelatus probably hides a species complex”.
description: Published as part of Zaragoza, Juan A. & Pérez, Toni, 2013, Hypogean pseudoscorpions (Arachnida) from Jaén province (Andalusia, Spain), with descriptions of four new species and a new synonymy, pp. 201-225 in Zootaxa 3700 (2) on pages 203-204, DOI: 10.11646/zootaxa.3700.2.1, http://zenodo.org/record/218268