Occidenchthonius gracilimanus Mahnert 1997, n. comb.
Creators: name: Zaragoza, Juan A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Occidenchthonius
Occidenchthonius gracilimanus

description: Occidenchthonius gracilimanus (Mahnert, 1997), n. comb.
(Fig. 250)
Chthonius (Ephippiochthonius) gracilimanus Mahnert 1997: 560 –562, figs 1–3.
Chthonius (Ephippiochthonius) gracilimanus: Mahnert 2011a: 42 (in part: Gran Canaria specimens misidentified; see under O. mahnerti n. sp.).
Type locality. Spain, Canary Islands, Santa Cruz de Tenerife province, La Palma Island, Mazo, Barranco el Cabrito, Salto de Tigalate (28°32′04″N, 17°47′38″W; 71 m a.s.l.).
Distribution. Spain: Canary Islands.
Diagnosis (♂ ♀). A small, microphthalmic, hypogean Occidenchthonius species of the machadoi -group. Movable cheliceral finger with isolated subapical tooth (di) and prominent spinneret in both sexes, lyrifissure ldb present; anterior pair of eyes with low lens or indistinct spots, posterior eyes absent, anterior margin of carapace with 1–2 preocular microsetae on each side, posterior margin with 2 macrosetae; chelal hand weakly depressed at level of ib / isb, with short and small hump distad of ib / isb and moderate slope between trichobothria ib / isb and eb, chaetotaxy 4:4:4; fixed chelal finger with 15–19 teeth; distal half of movable chelal finger with 11–12 pointed teeth with dental canals, basal half of movable chelal finger with 7–10 rounded, partially fused, vestigial teeth, without canals, on weakly raised lamina; pedipalpal femur (♂) 6.8–7.1, (♀) 6.3–6.9 times longer than broad, length (♂) 0.57–0.58 mm, (♀) 0.60–0.65 mm; chela (♂) 7.0–7.2, (♀) 6.0–6.8 times longer than deep, length (♂) 0.77–0.81 mm, (♀) 0.82–0.85 mm; ratio movable chelal finger/chelal hand (♂ ♀) 1.5–1.6; lacking lyrifissures ma1, ma2 and hd, all other chelal lyrifissure patterns present, most with their standard complements.
Type material examined. 1 ♀ paratype (MHNG), Spain, Canary Islands, Santa Cruz de Tenerife province, La Palma Island, Mazo, Barranco el Cabrito, Salto de Tigalate (28°32′04″N, 17°47′38″W; 71 m a.s.l.), 04.I.1994, leg. R. García Becerra.
Non-type material examined. 1 ♀, La Palma Island, Tijarafe, Cueva de las Palmeras (28°22′48″N, 16°43′31″W; 577 m a.s.l.), 12.VII.1986, leg. J.I. Martin.
Description (♂ ♀). Small, microphthalmic, hypogean species of MSS. Integument weakly depigmented; hispid granulation on lateral surfaces of carapace, on cheliceral hand and on bases of chelal fingers.
Carapace slightly longer than broad and weakly constricted posteriorly; medial part of anterior margin weakly prominent, without a well-defined epistome, and strongly dentate; anterior eyes reduced to small, low lens (diameter 0.035 mm) or indistinct spots with reflecting tapeta, 0.045 mm from anterior margin of carapace, posterior eyes practically absent. Chaetotaxy: 18 setae, with 1 (rarely 2) preocular microsetae on each side, 2 setae in posterior row, macrosetal formula 4:6:4:2:2, anteromedial setae 0.09–0.11 mm long, sublateral ocular setae 0.05 mm; 4 lyrifissures anteriorly and 2 posteriorly.
Cheliceral hand with 6 setae and 1–2 lateral microsetae, seta vb short (0.030 mm long), microsetae 0.020 mm; hand with 5 dorsal and 1 ventral lyrifissure, lyrifissure ldb present. Fixed finger with 7–10 teeth decreasing in size proximally, two distal teeth distinctly larger than others, about 3 proximal microtubercles. Movable finger with an isolated subapical tooth (di), with 4–8 teeth decreasing in size proximally, the distal tooth larger than others, 0–1 proximal microtubercles; spinneret small and apically rounded in both sexes; seta gl 0.54 from base of movable finger. Rallum with 11 blades. Serrula exterior with 15–16 blades.
Chaetotaxy of tergites 4:4:4:4:6:6:6:6:1T2T1:4:1T2T1:0, tergites IX and XI each with 2 sublateral tactile setae, tactile seta IX 0.19 mm long. Chaetotaxy of sternites 8–10:(3)7–9(3):(1–2)6–8(2–3):6–8:6:6:6:6:2T1T2:0:2, lateral setae on sternite III macrosetal in size, sternite X with 2 submedial tactile setae; in addition, genital notch of male flanked by 5–9 setae on each side and 4+4 internal glandular setae.
Pedipalpal coxa with 5 setae (including 2 on manducatory process), distal marginal seta of disk 0.08 mm long; coxa I 3 + 3 marginal microsetae, distal marginal seta 0.06–0.07 mm long; II 4 + 6–9 bipinnate coxal spines, III 5 + 3–7 bipinnate coxal spines and IV 6; intercoxal tubercle bisetose.
Pedipalp with femoral chaetotaxy 3:6:3:5:1. Chela (Fig. 250) with hand weakly depressed at level of ib / isb, with short and small hump distad of ib / isb and moderate slope between trichobothria ib / isb and eb; marked hollow before base of movable finger with thicker cuticle; width equal to or shorter than depth, maximum width proximad of trichobothria ib / isb; chaetotaxy 4:4:4, seta ph3 present, seta ih5 absent; distal end of hand and bases of chelal fingers with sclerotized condylar complex. Fixed finger with 15–19 mostly pointed teeth and with dental canals, two most proximal teeth distinctly reduced in size and the most proximal can be apically rounded, first two distal teeth small, third tooth of normal row (mt) of fixed finger weakly modified in shape and deviated in orientation with respect to the others, dental row reaching up to proximad of trichobothrium sb, 4–9 proximal microtubercles; tip of finger with an accessory tooth (td) on antiaxial face; tip of fixed chelal finger of male with a weak hollow on paraxial face, without subdistal protuberance (sp); 2–3 long antiaxial sensory setae (as) at the base, one level with and the others distad of lyrifissure fb, 0.038–0.045 mm long, distance between them 0.035 mm, fixed finger depth at the base 0.053 mm; 5 teeth at level of est / it occupying 0.1 mm, distance between successive apices 0.021–0.024 mm. Distal half of movable finger with 11–12 pointed teeth with dental canals that reach up to proximad of halfway between trichobothria st and sb, two distal teeth tiny; basal half of movable chelal finger with 7–10 rounded, partially fused, vestigial teeth, without canals, on weakly raised lamina; dental row reaching level of sensilla pc, about 4 microtubercles at base; basal apodeme long and apically indented; coupled sensilla pc between trichobothria sb and b, closer to sb. Trichobothria as in Fig. 250; trichobothrium ist level with or slightly proximad of esb and well proximad of lyrifissure fb; distance between ib / isb and esb approximately equal to that between ib / isb and the base of the hand; distance between st and sb only 1.2–1.4 times longer than that between sb and b; lacking lyrifissures ma1, ma2 and hd, all other chelal lyrifissure patterns present, most with their standard complements.
Measurements and ratios. Holotype and paratypes, male followeds, when different, by female in square bracket: Carapace 0.38–0.40/0.33–0.37 (1.1–1.2) [0.40–0.45/0.38–0.40]. Pedipalp: femur 0.57–0.58/0.08 (6.8–7.1) [0.61–0.65/0.09 (6.6–6.9)], patella 0.25/0.10–0.12 (2.0–2.4) [0.26–0.27/0.10–0.11 (2.5–2.6)], chela 0.77–0.81/ 0.11–0.12 (7.0–7.2) [0.82–0.85 (6.4–6.8)], hand 0.31–0.32 (2.6–2.9) [0.32–0.35 (2.5–2.6)], movable finger 0.47– 0.50 [0.51–0.53]; ratio movable finger/hand 1.5–1.6, femur/movable finger 1.2, femur/carapace 1.5 [1.4–1.5], chela/carapace 2.0 [1.9–2.1], chela/femur 1.4 [1.3]. Non-type female: Carapace 0.42/0.40 (1.0). Pedipalp: femur 0.60/0.10 (6.3), patella 0.26/0.11 (2.3), chela 0.82/0.14 (6.0)], hand 0.32 (2.4), movable finger 0.50; ratio movable finger/hand 1.5, femur/movable finger 1.2, femur/carapace 1.4, chela/carapace 2.0, chela/femur 1.4.
Remarks. Within the machadoi -group, O. gracilimanus (Mahnert, 1997) is endemic to La Palma Island (Canary Islands). Material previously recorded from Gran Canaria Island (Mahnert 2011a) is here assigned to O. mahnerti n. sp. The latter differs from O. gracilimanus by the presence of chelal lyrifissure hd. The above description incorporates in part that of Mahnert (1997).
description: Published as part of Zaragoza, Juan A., 2017, Revision of the Ephippiochthonius complex in the Iberian Peninsula, Balearic Islands and Macaronesia, with proposed changes to the status of the Chthonius subgenera (Pseudoscorpiones, Chthoniidae), pp. 1-221 in Zootaxa 4246 (1) on pages 158-161, DOI: 10.5281/zenodo.437611