Tyrannochthonius zhai Gao & Zhang & Chen 2020, sp. nov.
Creators: name: Gao, Zhizhong
name: Zhang, Feng
name: Chen, Huiming
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Tyrannochthonius
Tyrannochthonius zhai

description: Tyrannochthonius zhai sp. nov.
Figs. 4–6
urn:lsid:zoobank.org:act: DF1220A7-37B6-4608-A4BB-C01A5215B70D
Type material. Holotype female (Ps.- MHBU-GZ11060701): China, Guizhou Province, Xingyi City, Dushan Town, Jiangjia Cave, dark zone, [25°18'096”N, 105°36'007”E], 7 June 2011, Zuwei Zha leg.
Etymology. The specific epithet is a patronym in honor of Mr. Zuwei Zha, who collected the specimen.
Diagnosis. Small sized troglomorphic species (Body length 1.40); carapace without eyes or eyespots, both anterior and posterior margin with 4 setae respectively, without epistome; tergites I–III with 4 setae; chelal fixed finger with intercalary teeth, movable finger with numerous pointed retrorse and contiguous teeth; no chemosensory setae on dorsum of chelal hand.
Description. Adult female (Fig. 4).
Colour: Generally pale yellow, carapace, chelicera, pedipalps and tergites slightly darker, soft parts pale.
Chelicera (Figs 5C, 6B): Five setae on hand, all setae acuminate; movable finger with one medial seta; fixed finger and movable finger with about 10 teeth; galea represented by a very slight bump on movable finger; rallum (Fig. 6C) with 6 blades, distal one longer than others, all blades bipinnate.
Pedipalp (Figs 5A, 6 E–H): All setae acuminate; femur 6.00, patella 2.20, chela 6.37, hand 1.89 times longer than deep; movable finger 2.14 times longer than hand, without large basal apodeme, only slightly sclerotized section is present. Femur without tactile setae. Fixed chelal finger and hand with 8 trichobothria, movable chelal finger with 4 trichobothria: ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist forming a straight oblique row at base of fixed chelal finger; it slightly distal to est, situated subdistally; et slightly near to tip of fixed finger, very close to chelal teeth; xs situated distal to et, microsetae (chemosensory setae) absent on both palpal fingers; sb situated slightly closer to b than to st; b and t situated subdistally, t situated at same level as est; b situated basal to est; microsetae (chemosensory setae) absent on both palpal fingers. Sensilla absent. Chelal teeth (Fig. 6H) heterodentate: fixed finger with 22 large, slightly retrorse, well-spaced teeth, plus 15 small intercalary teeth; movable finger with 26 middle size retrorse, pointed and continuous teeth, without intercalary teeth.
Cephalothorax (Figs 5B, 6A): Carapace as broad as long; anterior margin smooth; lateral margins constricted posteriorly; without any traces of eyes; without epistome; with 16 setae arranged 4: 4: 4: 2: 2; without furrows. Chaetotaxy of coxae: 4: 3: 4: 4; manducatory process with two acuminate distal setae, anterior seta less than 1/2 length of medial seta; coxae II with 5–6 terminally indented coxal spines on each side, set in oblique row; intercoxal tubercle absent; without sub-oral seta.
Abdomen: Pleural membrane papillostriate. Tergites and sternites undivided; setae uniseriate and acuminate. Each tergite with four setae except last one which has two only. Sternal chaetotaxy V–XI: 8: 8: 10: 9: 10: 10: 8. Anterior genital operculum with 10 setae plus 8 setae on posterior margin.
Legs (Figs 6 I–J): Typical. Femur + patella of leg IV 2.90 times longer than deep; arolium slightly shorter than the claws, not divided; claws simple.
Measurements: (length/breadth or depth in mm, ratios in parentheses). Female holotype: Body length 1.40. Pedipalps: trochanter 0.24/0.14 (1.71), femur 0.84/0.14 (6.00), patella 0.33/0.15 (2.20), chela 1.21/0.19 (6.37), hand length 0.36/0.16 (1.89), movable finger length 0.77. Carapace 0.48/0.48 (1.00). Leg I: trochanter 0.15/0.11 (1.36), femur 0.44/0.07 (6.29), patella 0.24/0.06 (4.00), tibia 0.22/0.06 (3.67), tarsus 0.46/0.05 (9.20). Leg IV: trochanter 0.20/0.11 (1.82), femur + patella 0.61/0.21 (2.90), tibia 0.45/0.08 (5.63), basitarsus 0.19/0.06 (3.17), telotarsus 0.46/0.05 (9.20).
Remarks. Of the Chinese species, T. zhai has the same tergal chaetotaxy on tergites I–II as T. akaelus, T. harveyi and T. ganshuanensis (only 2 setae), but can be distinguished from T. akaelus and T. ganshuanensis by the number of setae on the anterior margin of carapace (T. zhai with 4, T. akaelus and T. ganshuanensis with 6; Mahnert (2009)) and by the stouter pedipalps (e.g. femur 6.00 times vs. 6.60 times; Mahnert (2009)). T. zhai differs from T. akaelus by the number of chelal teeth fixed finger with 22 large, slightly retrorse, well-spaced teeth, plus 15 small intercalary teeth in T. zhai but 43 pointed teeth of equal length in T. akaelus; movable finger with 26 middle-sized retrorse, pointed and continuous teeth in T. zhai but with 37 marginal teeth and 8 intercalary teeth in T. akaelus). It differs from T. harveyi by having only 2 setae on the posterior margin of the carapace (4 in T. harveyi), and the fixed chelal finger with 15 small intercalary teeth in T. zhai, whereas intercalary teeth are absent in T. harveyi.
description: Published as part of Gao, Zhizhong, Zhang, Feng & Chen, Huiming, 2020, Two new cave-dwelling species of Tyrannochthonius Chamberlin 1929 (Pseudoscorpiones: Chthoniidae) from the Guizhou karst, China, pp. 572-580 in Zootaxa 4853 (4) on pages 576-579, DOI: 10.11646/zootaxa.4853.4.6, http://zenodo.org/record/4411149