Occidenchthonius villacarrillo – Chthonius (Ephippiochthonius) villacarrillo

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Pequeño tamaño, longitud corporal: 1.3 mm. Troglomorfismo debil. Escudo prosómico sin rastro de ojos; dos macrosedas en el borde posterior, sin microsedas preoculares

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Phylum Arthropoda / Subphylum Chelicerata / Classis Arachnida / Ordo Pseudoscorpiones / Subordo Epiocheirata / Superfamilia Chthonioidea / Familia Chthoniidae / Genus Occidenchthonius / Species Occidenchthonius villacarrillo – Chthonius (Ephippiochthonius) villacarrillo

1 Departamento de Ecología, Facultad de Ciencias, Universidad de Alicante, E-03080 Alicante, Spain. E-mail: ja.zaragoza@ua.es
2 Grupo de Espeleología de Villacarrillo (G.E.V.). Plaza 28 de Febrero, 5-1ª-2ª. E-23300 Villacarrillo, Jaén, Spain.
E-mail: bioespeleologiaGEV@gmail.com

Localidad tí­pica: Cueva de la Morciguilla, Villacarrillo, Jaén.
Descripción: Pequeño tamaño, longitud corporal: 1.3 mm. Troglomorfismo debil. Escudo prosómico sin rastro de ojos; dos macrosedas en el borde posterior, sin microsedas preoculares. Quelí­cero con seis sedas en la mano y una microseda lateral; tubérculo sedicí­gero prominente y apicalmente redondeado en la hembra; con un diente suabpical aislado en el dedo móvil. Terguitos 1:-VI: 4:4:4:4:6:6. Coxa II con 9-11 espinas, III con 4. Pedipalpos: mano de la quela marcadamente deprimida a nivel de los tricobotrios ib-isb, seguida de una corta protuberancia distal, levemente angulosa; tricobotrio ist distal de esb; dedo fijo con 18 dientes puntiagudos, móvil con 12 dientes puntiagudos seguidos de lámina proximal con 10 dientes vestigiales redondeados que alcanzan hasta media distancia entre los tricobotrios sb y b. Longitudes en mm. y ratios del pedipalpo en la hembra holotipo: fémur 0.56 (5 .5x), patela 0.23 (2.0x), quela lateral 0.78 (5.18x); mano lateral 0.32 (2.12x); dedo móvil 0.45; ratio dedo/mano 1.4x.


This species is dedicated to the municipal area of Villacarrillo where the type locality is found and
home town of G.E.V.; noun in apposition.


Weakly troglomorphic facies. No eyes or eye-spots. Chelicera with 6 setae on palm and one
microseta, movable cheliceral finger with isolated subapical tooth, female with distinct spinneret. Carapace with
two macrosetae on posterior margin, without preocular microsetae. Pedipalp: femur length 0.56 mm (5.5×); chela
length 0.78 (5.18×); fixed finger with 19 teeth, movable finger with 12 teeth and raised lamina with 9 rounded
vestigial teeth; trichobothrium ist markedly distal of eb/esb.


Small hypogean species; moderate troglomorphic adaptations; integument depigmented, pale
yellowish-brown; weak hispid granulation on lateral surface of ocular and posterior areas of carapace, on cheliceral
palm, on base of paraxial face of pedipalpal femur, on base of movable chelal finger and on dorsodistal surface of
pedipalpal hand.
Carapace (Fig. 21) as broad as long, slightly constricted posteriorly, subquadrate; anterior margin (Fig. 22)
prominent, medially dentate and with rudimentary epistome; without eyes or eye-spots; chaetotaxy: 18 setae,
without preocular microsetae, formula: 4:6:4:2:2, anteromedial seta 0.083 mm long, ocular seta 0.055 mm. Four
lyrifissures in anterior and ocular areas, two in posterior area.
Pedipalpal coxa 5 setae (including 2 on manducatory process), coxa I 3 + 3 marginal microsetae, II 4 + 9–11
bipinnate coxal spines, III 5 + about 4 (coxae strongly constricted) 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 9 setae on sternite II. Chaetotaxy of
sternites III–XI: (3)8(3):(2)7(2):8:6:6:6:6:7:0. Anal cone 0+2 setae.
Chelicera (Figs 23–24) with 6 setae on palm and 1 microseta laterally, seta vb very short, 0.025 mm long,
microseta 0.02 mm long; seta gl 0.53 from base of movable finger. Fixed finger with 11 teeth, two distal teeth
distinctly larger than others, proximally decreasing in size. Movable finger with an isolated subapical tooth (di), a
large distal tooth and 7 contiguous teeth reduced in size proximally; spinneret prominent and apically rounded.
Rallum with 11 blades, serrulae exterior and interior with 15 and 13 blades respectively.

Pedipalp (Figs 25–26) with femoral chaetotaxy 3:6:3:5:1, four lyrifissures: one antiaxial and three paraxial.
Chelal hand depressed at level of ib-isb, with a rounded hump, slightly abrupt, distad of ib-isb, and a marked
ventral hollow just before base of movable chelal finger; chaetotaxy 4:5:4. Fixed finger with 18 pointed teeth and
one rounded proximal tooth, all with dental canals except the two small distal ones; third distal tooth from tip
modified, a little wider than others; four microtubercles at base; tip of finger with an accessory tooth (td) on
antiaxial face; six teeth at level of est/it occupying 0.1 mm, distance between apices 0.015–0.018 mm. Distal half
of movable finger with 12 pointed teeth with dental canals, except distal tiny one and three proximal ones,
decreasing in size; proximal half of finger with slightly raised lamina with 9 rounded vestigial teeth reaching
halfway between trichobothria sb and b; coupled sensilla pc between sb and b, slightly closer to sb; basal apodeme
long and apically indented. Trichobothria as in fig. 25; ist markedly distal of esb, distance ist to esb 0.035 mm,
distance esb to eb 0.02 mm.
Leg IV. Tactile seta ratios: tibia 0.53, basitarsus 0.43, tarsus 0.33.
Measurements and ratios. Body 1.30. Carapace 0.41/0.41 (1.0). Chelicera: palm 0.36/0.17 (2.1), movable
finger 0.19. Pedipalp: femur 0.56/0.10 (5.5); patella 0.23/0.11 (2.0); chela width and depth 0.78/0.15 (5.2); hand
0.32 (2.1), length/depth (2.1); movable finger 0.45; ratio movable finger/hand 1.4; ratio femur/movable finger 1.3;
ratio femur/carapace 1.4, ratio chela/carapace 1.9. Leg I: femur 0.29/0.05 (5.4); patella 0.15/0.05 (3.1); tibia 0.17/
0.04 (4.1); tarsus 0.31/0.03 (9.2); ratio femur/patella 2.0. Leg IV: femur+patella 0.43/0.16 (2.7); tibia 0.28/0.07
(4.1); basitarsus 0.15/0.05 (3.0); telotarsus 0.30/0.03 (10.0); ratio telotarsus/basitarsus 2.0.
Remarks. Among the Iberian species with a raised lamina on movable chelal finger, with an isolated subapical
tooth on the movable finger of the chelicera and only two macrosetae on the posterior margin of the carapace, C.
(E.) villacarrillo differs from C. (E.) machadoi Vachon, 1940 (Algarve, Portugal) (Vachon 1940a) by the markedly
distal position of trichobothrium ist with respect to esb (basal in machadoi), and in being eyeless. From the epigean
species C. (E.) minutus Vachon, 1940 (Algarve, Portugal), with similar pedipalp measurements, C. (E.)
villacarrillo can be distinguished by the absence of preocular microsetae and the large lamina on the proximal half
of the movable chelal finger, with 9 rounded vestigial teeth reaching halfway between trichobothria sb and b,
versus one preocular microseta on each side and a short proximal lamina with 6 rounded vestigial teeth reaching to
level of sb in C. (E.) minutus. Chthonius (E.) morenoi Carabajal Márquez, García Carrillo & Rodríguez Fernández,
2011 (Córdoba, Spain) bears two preocular microsetae on each side and has strong troglomorphic facies with extreme pedipalp ratios (Carabajal Márquez et al. 2011), making it very different to C. (E.) villacarrillo. In addition
to the three characters mentioned above, C. (E.) villacarrillo shares the absence of preocular microsetae with the
hypogean species Chthonius (E.) sendrai Zaragoza, 1985 (Valencia, Spain) and Chthonius (E.) ambrosiae
Carabajal Márquez, García Carrillo & Rodríguez Fernández, 2012 (Cádiz, Spain), but it is distinctly different from
both of them by its markedly smaller size and robust chelal ratios: e.g. femur 0.56/0.10 (5.5) and chela 0.78/0.15
(5.18) in the new species, femur 0.86/0.12 (7.21) and chela 1.19/0.17 (7.0) in C. (E.) sendrai (Zaragoza 1985a),
femur 1.19/0.15 (8.16) and chela 1.68/0.24 (6.9) in C. (E.) ambrosiae (Carabajal Márquez et al. 2012).
The type specimen of C. (E.) minutus, deposited in MNHN, has been examined and used for the above
comparison (full data to be given elsewhere). Carabajal Márquez et al. (2011) identified as C. (E.) minutus a
sample from Córdoba province and included the species in their key to the Andalusian Ephippiochthonius. In our
opinion, this record must be discarded, in view of the distance between Algarve and Córdoba and the high
endemicity displayed by subterranean Ephippiochthonius species.
Distribution. Andalusia, Spain

FIGURES 25–26. Chthonius (Ephippiochthonius) villacarrillo sp. nov., female holotype. 25, left pedipalp, minus chela and
trochanter, dorsal view; 26, left chela, lateral view. Scale bar 0.2 mm.

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