Occidenchthonius oromii Zaragoza, 2017, n. sp.
Creators: name: Zaragoza, Juan A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Occidenchthonius
Occidenchthonius oromii

description: Occidenchthonius oromii n. sp. (Figs 291–295)
Type locality. Spain, Canary Islands, Santa Cruz de Tenerife province, Tenerife Island, Icod de los Vinos, Cueva Felipe Reventón (28°21′11″N, 16°42′33″W; 535 m a.s.l.).
Distribution. Spain: Canary Islands.
Etymology. The species is named after Dr Pedro Oromí (DZUL), honouring his great contribution to the knowledge of the Canarian fauna of the subterranean environment.
Diagnosis (♀). A small, hypogean Occidenchthonius species of the machadoi -group. Movable cheliceral finger with isolated subapical tooth (di) and with prominent spinneret in female, unknown for male, lyrifissure ldb present; without eyes or eye-spots, anterior margin of carapace with 2 preocular microsetae on each side, posterior margin with 2 medial macrosetae; chelal hand distinctly depressed at level of ib / isb, with short and prominent hump distad of ib / isb and moderate slope between trichobothria ib / isb and eb, chaetotaxy 4:4:4; fixed chelal finger with 15 teeth; distal half of movable chelal finger with 10 pointed teeth with dental canals, basal half of movable chelal finger with 9 rounded, partially fused, vestigial teeth, without canals, on weakly raised lamina; pedipalpal femur (♀) 5.2 times longer than broad, length 0.51 mm; chela (♀) 5.0 times longer than deep, length 0.73 mm; ratio movable chelal finger/chelal hand (♀) 1.4; lacking lyrifissures ma1 and ma2, all other chelal lyrifissure patterns present with their standard complements.
Type material examined. ♀ holotype (MCNB), Spain, Canary Islands, Santa Cruz de Tenerife province, Tenerife Island, Icod de los Vinos, Cueva Felipe Reventón (28°21′11″N, 16°42′33″W; 535 m a.s.l.), VIII.1986, leg. Ll. Auroux.
Description (♀; ♂ unknown). Small, hypogean species. Integument weakly depigmented; weak hispid granulation on lateral surfaces of carapace, on cheliceral hand and on bases of chelal fingers.
Carapace (Fig. 292) as long as broad and distinctly constricted posteriorly; medial part of anterior margin distinctly prominent, without a well-defined epistome, and strongly dentate (Fig. 291); without eyes or eye-spots. Chaetotaxy: 18 macrosetae, with 2 preocular microsetae on each side, posterior margin with 2 medial macrosetae, setal formula: mm 4mm:6:4:2:2, anteromedial setae 0.095 mm long, sublateral ocular setae 0.060 mm; 4 lyrifissures anteriorly and 2 posteriorly.
Chelicera (Figs 293, 294) with 6 setae and 3 lateral microsetae on hand, seta vb very short (0.020 mm long); hand with 5 dorsal and 1 ventral lyrifissure, lyrifissure ldb present. Fixed finger with 8 teeth decreasing in size proximally, two distal teeth distinctly larger than others, 3 proximal microtubercles. Movable finger with an isolated subapical tooth (di), with 6 teeth decreasing in size proximally, the distal tooth larger than others; spinneret small in female (Fig. 294), unknown for male; seta gl 0.56 from base of movable finger. Rallum with 11 blades. Serrula exterior with 15 blades, serrula interior with 13 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 10:(3)7(3):(2)6(2):8:6–7:6:6:6:2T1T2:0:2, 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 + 6 bipinnate coxal spines, III 5 + 3 bipinnate coxal spines and IV 6; intercoxal tubercle bisetose.
Pedipalp with femoral chaetotaxy 3:6:3:5:1. Chela (Fig. 295) with hand distinctly depressed at level of ib / isb, with short and prominent 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 4:4:4, seta ph3 present, seta ih5 absent, seta dh3 removed close to the intermediate setal row; distal end of hand and bases of chelal fingers with sclerotized condylar complex. Fixed finger with 15 pointed teeth and with dental canals, 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 slightly distad of trichobothrium sb, 7–8 microtubercles at base; tip of finger with an accessory tooth (td) on antiaxial face; one pair of long antiaxial sensory setae (as) at the base, one level with and other distinctly distad of lyrifissure fb, 0.030 mm long, distance between them 0.020 mm, fixed finger depth at the base 0.040 mm; 5 teeth at level of est / it occupying 0.1 mm, distance between successive apices 0.025 mm. Distal half of movable finger with 10 pointed teeth with dental canals that reach up to halfway between trichobothria st and sb, one distal teeth tiny; basal half of movable chelal finger with 9 rounded, partially fused, vestigial teeth, without canals, on weakly raised lamina; dental row reaching slightly proximad of sb, 3 microtubercles at base; basal apodeme long and apically indented; coupled sensilla pc between sb and b, slightly closer to sb. Trichobothria as in Fig. 295; trichobothrium ist distinctly distad of esb and well proximad of lyrifissure fb; trichobothria eb–esb -ist in a straight line; distance between ib / isb and base of hand approximately equal to that between ib / isb and esb; distance between st and sb 2.0 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 1.22. Carapace 0.40/0.38 (1.1). Chelicera 0.33/0.16 (2.1), movable finger 0.17. Pedipalp: femur 0.51/0.10 (5.2), patella 0.22/0.11 (2.0), chela 0.73/0.15 (5.0), hand 0.30 (2.0), movable finger 0.42; ratio movable finger/hand 1.4, femur/movable finger 1.2, femur/carapace 1.3, chela/carapace 1.8, chela/femur 1.4.
Remarks. Occidenchthonius oromii n. sp. is a Canarian species of the machadoi -group endemic to the island of Tenerife. It shares with O. lopezi, O. setosus (Mahnert, 1993) and O. tenerifae the absence of eyes. It differs from O. lopezi and O. tenerifae in having only 2 setae on the posterior margin of the carapace, as opposed to 4. The presence of only 2 preocular microsetae on each side makes O. oromii n. sp. easily distinguishable from O. setosus, which has numerous microsetae anteriorly.
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 184-186, DOI: 10.5281/zenodo.437611