Occidenchthonius dubius Mahnert 1993, n. comb.
Creators: name: Zaragoza, Juan A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Occidenchthonius
Occidenchthonius dubius

description: Occidenchthonius dubius (Mahnert, 1993), n. comb.
(Fig. 231)
Chthonius (Ephippiochthonius) dubius Mahnert 1993: 976 –979, figs 13–16, table 1.
Not Chthonius (Ephippiochthonius) dubius: Mahnert 2011a: 41 –42 (misidentification, see O. beieri).
Type locality. Spain, Canary Islands, Santa Cruz de Tenerife province, Tenerife Island, Icod de los Vinos, Cueva de San Marcos (28°22′48″N, 16°43′31″W; 8 m a.s.l.).
Distribution. Spain: Canary Islands.
Diagnosis (♀). A small, microphthalmic hypogean Occidenchthonius species. Movable cheliceral finger with isolated subapical tooth (di) and with prominent spinneret in female, unknown for male, lyrifissure ldb absent; anterior pair of eyes with low lens, posterior eyes absent, anterior margin of carapace without preocular microsetae, posterior margin with 2 macrosetae; chelal hand distinctly depressed at level of ib / isb, with a hump distad of ib / isb and moderate slope between trichobothria ib / isb and eb; chaetotaxy 4:5:4; fixed chelal finger with 17 teeth; distal half of movable chelal finger with 10 pointed teeth with dental canals, basal half of movable chelal finger with 12 rounded, partially fused, vestigial teeth, without canals, on raised lamina; pedipalpal femur (♀) 5.1 times longer than broad, length 0.49 mm; chela (♀) 4.6 times longer than deep, length 0.70 mm; ratio movable chelal finger/ chelal hand (♀) 1.4; lacking lyrifissures ma1 and ma2, all other patterns present with their standard complements.
Type material examined. ♀ holotype (MHNG), Spain, Canary Islands, Santa Cruz de Tenerife province, Tenerife Island, Icod de los Vinos, Cueva de San Marcos (28°22′48″N, 16°43′31″W; 8 m a.s.l.), 10.IX.1992, leg. P. Strinati.
Description (♀; ♂ unknown). Small, microphthalmic, hypogean species. Integument weakly depigmented; weak hispid granulation on posterolateral 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 distinctly prominent, without a well-defined epistome, and strongly dentate; anterior eyes small with low convex lens and reflecting tapetum, their diameter equal to their distance from the anterior margin of carapace, posterior eyes absent. Chaetotaxy: 18 setae, without preocular microsetae, 2 setae in posterior row, formula 4:6:4:2:2, anteromedial setae 0.07 mm long, sublateral ocular setae 0.06 mm.
Cheliceral hand with 6–7 setae and 1–2 lateral microsetae, seta vb short (length 0.030 mm), microsetae 0.027 mm; hand with 4 dorsal and 1 ventral lyrifissure, lyrifissure ldb absent. Fixed finger with 7 teeth decreasing in size proximally, two distal teeth distinctly larger than others, 2 proximal microtubercles. Movable finger with an isolated subapical tooth (di), with 7 teeth decreasing in size proximally, the distal tooth larger than others; spinneret prominent and apically rounded in female, unknown for male; seta gl 0.51 from base of movable finger. Rallum with 11 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. Chaetotaxy of sternites 9:(3)8(3):(2)6(2):8:6:6:6:6:2T1T2:0:2, lateral setae on sternite III macrosetal in size, sternite X with 2 submedial tactile setae.
Pedipalpal coxa with 5 setae (including 2 on manducatory process), distal marginal seta of disk 0.07 mm long; coxa I 3 + 3 marginal microsetae, distal marginal seta 0.05 mm long; II 4 + 13–14 bipinnate coxal spines, III 5 + 6– 7 bipinnate coxal spines and IV 6; intercoxal tubercle bisetose.
Pedipalp with femoral chaetotaxy 3:6:3:5:1. Chela (Fig. 231) with hand distinctly depressed at level of ib / isb, with a 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 shorter than depth; chaetotaxy 4:5:4, setae ph3 and ih5 present; distal end of hand and bases of chelal fingers with sclerotized condylar complex. Fixed finger with 17 mostly pointed teeth and with dental canals, 5 most proximal teeth progressively decreasing in size, first two distal teeth small, third tooth of normal row (mt) of fixed finger distinctly modified in shape and deviated in orientation with respect to the others, dental row reaching up to halfway between trichobothria sb and b, 7 proximal microtubercles; tip of finger with an accessory tooth (td) on antiaxial face; one pair of long antiaxial sensory setae (as) at the base, on either side of lyrifissure fb, 0.038 mm long, distance between them 0.025 mm, fixed finger depth at the base 0.045 mm; 6 teeth at level of est / it occupying 0.1 mm, distance between successive apices 0.019–0.021 mm. Distal half of movable finger with 10 mostly pointed teeth with dental canals that reach up to slightly distad of halfway between trichobothria st and sb, the most proximad tooth slightly reduced in size and apically rounded, two distal ones tiny; basal half of movable chelal finger with 12 rounded, partially fused, vestigial teeth, without canals, on weakly raised lamina; dental row reaching up to halfway between trichobothria sb and b; basal apodeme long and apically indented; coupled sensilla pc between sb and b, slightly closer to sb. Trichobothria as in Fig. 231; trichobothrium ist distinctly distad of esb and very slightly 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 1.8 times longer than that between sb and b; lacking lyrifissures ma1 and ma2, all other chelal lyrifissure patterns present with their standard complements.
Measurements and ratios. Female holotype: Body 1.52. Carapace 0.44/0.41 (1.1). Chelicera 0.34/0.17 (2.1), movable finger 0.18. Pedipalp: femur 0.49/0.10 (5.1), patella 0.21/0.11 (2.0), chela 0.70/0.15 (4.6), hand 0.29 (1.9), movable finger 0.40; ratio movable finger/hand 1.4, femur/movable finger 1.2, femur/carapace 1.1, chela/carapace 1.6, chela/femur 1.4.
Remarks. Occidenchthonius dubius is endemic to Tenerife Island. It is the only representative of Occidenchthonius from the Canary Islands that does not belong to the machadoi -group, due to the presence of the chelal hand seta ih5, the absence of cheliceral lyrifissure ldb, and the absence of preocular microsetae. Nor can it be assigned to the verai -group. Records of O. dubius from Gran Canaria given by Mahnert (2011a) are misidentifications of O. beieri n. sp. (see remarks under that species). Comparisons with other species are made in the key and in the remarks under O. anae n. sp. The above description incorporates in part that of Mahnert (1993).
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 145-146, DOI: 10.5281/zenodo.437611