Occidenchthonius tamaran Mahnert 2011, n. comb.
Creators: name: Zaragoza, Juan A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Occidenchthonius
Occidenchthonius tamaran

description: Occidenchthonius tamaran (Mahnert, 2011), n. comb.
(Fig. 317)
Chthonius (Ephippiochthonius) tamaran Mahnert 2011a: 29 –31, figs 5–9.
Type locality. Spain, Canary Islands, Las Palmas province, Gran Canaria Island, Santa Lucía de Tirajana, Cueva de los Arrepentidos (27°50′36″N, 15°36′34″W; 310 m a.s.l.).
Distribution. Spain: Canary Islands.
Diagnosis (♂ ♀). A microphthalmic hypogean, medium-sized Occidenchthonius species of the machadoi - group. Movable cheliceral finger with isolated subapical tooth (di) and with small spinneret in both sexes; anterior pair of eyes with flat lens, posterior reduced to eye-spots, anterior margin medially straight, anterior margin of carapace with 2–3 preocular microsetae on each side, posterior margin with 2 macrosetae; chelal hand distinctly depressed at level of ib / isb, with prominent hump distad of ib / isb and moderate slope between trichobothria ib / isb and eb, chaetotaxy 4:4:4; fixed chelal finger with 17–19 teeth; distal half of movable chelal finger with 9–10 pointed teeth with dental canals, basal half of movable chelal finger with 9–12 rounded, partially fused, vestigial teeth, without canals, on raised lamina; pedipalpal femur (♂) 6.8–7.2, (♀) 6.0–6.9 times longer than broad, length (♂) 0.62–0.65 mm, (♀) 0.63–0.72 mm; chela (♂) 5.9–6.5, (♀) 5.5–6.2 times longer than deep, length (♂) 0.79– 0.88 mm, (♀) 0.84–0.95 mm; ratio movable chelal finger/chelal hand (♂ ♀) 1.5–1.6; lacking lyrifissures ma1 and ma2, all other chelal lyrifissure patterns present with their standard complements.
Type material examined. 1 ♂ paratype (MHNG), Spain, Canary Islands, Las Palmas province, Gran Canaria Island, municipal area of Telde, Barranco del Draguillo (27°56′51″N, 15°27′10″W; 440 m a.s.l.), MSS, 26.XII.2006, leg. H. López.
Description (♂ ♀). Medium-sized, 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 approximately as long as broad and not constricted posteriorly; medial part of anterior margin straight and strongly dentate; anterior eyes with flat lens, separated by half of their diameter from anterior margin of carapace, posterior eyes reduced to eye-spots. Chaetotaxy: 18 setae, usually with 2–3 preocular microsetae on each side, 2 setae in posterior row, macrosetal formula 4:6:4:2:2.
Cheliceral hand with 6 setae and 2–4 lateral microsetae, seta vb short. Fixed finger with 8–11 teeth decreasing in size proximally, two distal teeth distinctly larger than others. Movable finger with an isolated subapical tooth (di), with 4–8 teeth decreasing in size proximally; spinneret small in both sexes. Rallum with 11 blades. Serrula exterior with 14–15 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)6–8(3):(2)6–8(2):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 setae on each side and 4+4 internal glandular setae.
Pedipalpal coxa with 5 setae (including 2 on manducatory process), coxa I 3 + 3 marginal microsetae, II 4 + 7– 10 bipinnate coxal spines, III 5 + 3–5 bipinnate coxal spines and IV 6; intercoxal tubercle bisetose.
Chela (Fig. 317) with hand distinctly depressed at level of ib / isb, with 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; 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 17–19 mostly pointed teeth and with dental canals, last 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 slightly proximad halfway between trichobothria sb and b, 5 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); one pair of long antiaxial sensory setae (as) at the base, both distad of lyrifissure fb, 0.040 mm long, distance between them 0.035 mm, fixed finger depth at the base 0.050 mm; 5 teeth at level of est / it occupying 0.1 mm, distance between successive apices 0.020–0.025 mm. Distal half of movable finger with 9–10 pointed teeth with dental canals that reach up to proximad of trichobothrium st, the distal tooth tiny on low protuberance; basal half of movable chelal finger with 9–12 rounded, partially fused, vestigial teeth, without canals, on raised lamina; dental row reaching up to proximad of sb; basal apodeme long and apically indented; coupled sensilla pc between trichobothria sb and b, closer to sb. Trichobothria as in Fig. 317; trichobothrium ist slightly distad of esb and well proximad of lyrifissure fb, trichobothria eb -esb -ist in a straight line; distance between ib / isb and base of finger 1.2 times longer than that between ib / isb and esb; distance between st and sb 1.9 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 and female paratypes, followed, when different, by male paratypes in square brackets: Body 1.30–1.70. Carapace 0.44–0.48/0.44–0.49 (1.0) [0.39–0.43/0.38–0.42]. Pedipalp: femur 0.63–0.72/0.10–0.12 (6.0–6.9) [0.62–0.65/0.09–0.10 (6.8–7.2)], patella 0.26–0.30/0.12–0.14 (2.1–2.5) [0.24–0.25/ 0.11–0.12 (2.0–2.1)], chela 0.84–0.95/0.15–0.16 (5.5–6.2) [0.79–0.88/0.13–0.14 (5.9–6.5)], hand 0.33–0.38 (2.2– 2.5) [0.32–0.34 (2.4–2.6)], movable finger 0.51–0.58 [0.50–0.54]; ratio movable finger/hand 1.5– 1.6, femur/ movable finger 1.2, femur/carapace 1.4–1.5 [1.5–1.6], chela/carapace 1.9–2.0, chela/femur 1.3 [1.3–1.4].
Remarks. Occidenchthonius tamaran is endemic to Gran Canaria Island. Within the machadoi -group, it resembles O. beieri in the reduction of the eyes (microphthalmic), the morphometric measurements, the chelal teeth arrangement and in having 2 setae in the posterior row of the carapace. Detailed comparisons between these species are made in the remarks under O. beieri and in the key. The above description incorporates in part that of Mahnert (2011a).
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 203-205, DOI: 10.5281/zenodo.437611