Rhacochelifer gaeli Hernández-Corral & Zaragoza & Micó 2018, n. sp.
Creators: name: Hernández-Corral, Jesús
name: Zaragoza, Juan A.
name: Micó, Estefanía
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Cheliferidae
Rhacochelifer
Rhacochelifer gaeli

description: Rhacochelifer gaeli Zaragoza & Hernández-Corral n. sp.
(Figs 5, 26‒33)
Type locality. Spain, Castilla y León Community, Salamanca province, La Bastida (40°35′37″N, 06°03′16″W).
Distribution. Spain: Castilla y León Community.
Etymology. This species is dedicated to the grandson of the first author (JHC), Gael Villegas Hernández.
Diagnosis (Ƌ). Small Rhacochelifer species without coarser granules on carapace and pedipalps and with moderately elongated keels on posterolateral corners of carapace and anterior tergites (I‒IV) in males. Hemitergites without medial setae. Pedipalpal femur 3.7 times longer than broad, length 0.66 mm, chela+ 3.7 times longer than broad, length 0.95 mm. Tarsus of leg I 2.7 times longer than deep, dorsal margin indistinctly convex, distal margin slightly concave.
Type material examined. ♂ holotype (CEUA 00106324), Spain, Castilla y León Community, Salamanca province, La Bastida, WT, 23.X.2012, leg. A. García-López, E. Micó & A. Ramírez-Hernández.
Description (Ƌ; ♀ unknown). Moderately small, epigean species (Fig. 5). Body and pedipalps dark brown, legs slightly paler. Vestitural setae slightly clavate, but acuminate on sternites.
Carapace granulate, without coarser granules; two transverse furrows, posterolateral corners with elongated lateral keels. Setae short, clavate and apically dentate, chaetotaxy 35:20:11(66), 4 setae on anterior margin, metazone with 9 posteromarginal setae and 1 lateromedial seta on each side. One pair of well developed eyes, diameter 0.05 mm, distance to anterior margin 0.055 mm.
Chelicera (Fig. 26) with 5 setae on hand, ib finely dentate, the others smooth. Fixed finger with 3 tiny distal teeth, followed by 3 large teeth. Movable finger with seta gl 0.9 from base; distally with three low tubercles, the distal one level with gl; galea with 6 apical rami; rallum with 3 blades, distal blade with 6 teeth; serrula exterior with 16 blades.
Tergites I‒XI divided. Tergites I‒IV with elongate lateral keels on posterolateral corners; in addition to the marginal row (Fig. 27), some tergites with a medial row of setae, hemitergite IV with one lateromedial seta, hemitergites V‒X with one lateral and one discal seta, medial setae absent in all tergites; chaetotaxy of hemitergites 6‒7:7:5‒6:7‒8:6‒7:7‒8:7‒8:7‒8:7:6:5, tergite XI with 2 tactile setae, apically acuminate, length 0.08 mm, tergite XII with 2 setae. Anterior genital opening with 5 short discal setae and 20 long posterior setae, posterior with 10, 4 internal setae; hemisternites IV‒X 4‒5:5:5‒6:5‒6:4‒5:6:5, sternites XI‒XII undivided, XI 10 (2 tactile setae, length 0.12 mm) setae, XII 2 setae.
Pedipalpal coxa with 4 setae on manducatory process (including suboral seta), and 11‒12 setae on the disk, leg coxae I 6, II 8‒9, III 9‒10, IV 25 setae.
Pedipalps (Figs 28‒32) with granulation, more pronounced paraxially, without coarser granules. Trochanter with prominent, rounded, antiaxial hump, femur not pedicellate, maximum width distad of middle. Fixed chelal finger with 31 teeth, movable with 34 (Figs 31‒32); venom ducts in both fingers, nodus ramosus midway between trichobothria est and et in fixed finger and distad of trichobothrium t in movable finger. Trichobothria as in Figs 29‒30; it slightly proximad of ist; est distinctly distad of ist.
Leg I tarsus (Fig. 33) with dorsal margin indistinctly convex, distal margin slightly concave, claws asymmetric. Leg IV tarsus without tactile seta. All legs with dentate subterminal setae on tarsi.
Measurements (mm) and ratios. Male holotype. Body 1.80. Carapace 0.65/0.68 (1.0). Chelicera 0.20/0.11 (1.9), movable finger 0.14. Pedipalp: trochanter 0.31/0.19 (1.6), femur 0.66/0.18 (3.7), patella 0.56/0.21 (2.7), hand+ 0.54/0.26 (2.1), hand - 0.47 (1.8), movable finger 0.41, chela+ 0.95/0.26 (3.7), chela - 0.89 (3.4); ratio movable finger/hand+ 1.3, femur/movable finger 1.6, femur/carapace 1.0, femur/patella 1.2, patella/hand+ 1.0, chela+/ carapace 1.5, chela+/femur 1.4. Leg I: femur+patella 0.36/0.12 (3.0), femur 0.22/0.12 (1.8), patella 0.25/0.11 (2.4), tibia 0.28/0.11 (2.6), tarsus 0.27/0.10 (2.7). Leg IV: femur+patella 0.51/0.18 (2.8), femur 0.17/0.11 (1.5), patella 0.43/0.18 (2.4), tibia 0.39/0.10 (3.8), tarsus 0.30/0.07 (4.1).
Remarks. Amongst the species of Pseudorhacochelifer and Rhacochelifer with elongated keels on the posterolateral corners of the carapace and anterior tergites in males, Rhacochelifer gaeli n. sp. is similar in size to R. euboicus, but differs in having a more slender pedipalp chela+ (3.7 times longer than broad versus 3.3‒3.4) and tibia leg I (2.6 times longer than deep, versus 2.0‒2.1), a slightly more slender tarsus I and, in particular, by the absence of medial setae on all tergites, which are present in all the R. euboicus males examined here. The new species is distinguishable from the other two Rhacochelifer species with keels, Rhacochelifer peculiaris (L. Koch, 1873) and Rhacochelifer tauricus (Beier, 1969) (Beier 1963, 1969; Heurtault 1980), by the less robust foretarsus than R. gaeli n. sp. and by differences in size, with R. peculiaris having larger and R. tauricus smaller pedipalp measurements. It shares with Pseudorhacochelifer coiffaiti (Vachon, 1961) and P. schurmanni the absence of coarser granules on the carapace and pedipalp (Beier 1976; Vachon 1961) and the absence of medial setae on the tergites, but R. gaeli n. sp. differs from them in having smaller and stouter pedipalps and the male lateral keels not prolonged after tergite IV, whereas in both Pseudorhacochelifer species the keels are prolonged to at least tergite VI (data concerning P. coiffaiti provided by Mark Judson, in litt.).
According to our current knowledge, the differences between the genera Pseudorhacochelifer and Rhacochelifer are not consistent. Diagnostic characteristics of Pseudorhacochelifer given in relation to Rhacochelifer, such as slender pedipalps, pedipalpal femur not abruptly pedicellate and the presence in males of lateral keels on the posterolateral corners of the carapace and tergites (Beier 1976), are also found in some Rhacochelifer species. Concerning the lateral keels of the tergites, in Pseudorhacochelifer these usually occur on tergites I to VII‒VIII in P. canariensis Mahnert, 1997, VI‒VII in P. coiffaiti (Mark Judson, in litt.), VIII in P. schurmanni (pers. obs.), but only to IV‒V in P. spiniger (Mahnert (1978), confirmed by restudy of a specimen from Sintra, Portugal, recorded by Lissner & Zaragoza (2017). In Rhacochelifer they extend to tergite IV in R. gaeli n. sp., IV‒VI in R. euboicus and VI in R. tauricus (distribution unknown in R. peculiaris). Given the small differences in the number of tergites involved and the variability observed, this cannot be used to distinguish these genera. Thus the possibility that they will prove to be synonymous after additional study cannot be excluded. Although R. gaeli n. sp. is geographically closer to the known distribution of Pseudorhacochelifer species and far from the other three Rhacochelifer species with lateral keels on the posterolateral corners of the carapace and anterior tergites in males, we have opted to assign it to the genus Rhacochelifer.
description: Published as part of Hernández-Corral, Jesús, Zaragoza, Juan A. & Micó, Estefanía, 2018, New species of Pseudoscorpiones (Arachnida) from tree hollows in a Mediterranean oak forest in Spain, pp. 201-225 in Zootaxa 4497 (2) on pages 214-216, DOI: 10.11646/zootaxa.4497.2.3, http://zenodo.org/record/1452117