﻿Three new species of cave-adapted pseudoscorpions (Pseudoscorpiones, Chthoniidae) from eastern Yunnan, China

﻿Abstract Three new cave-adapted chthoniid pseudoscorpions from four karst caves of Yunnan Province (China) are described, including detailed diagnosis and illustrations: Tyrannochthoniuscalvatussp. nov. from an unnamed cave and Dongtianfu Cave (Fuyuan County), T.capitosp. nov. from Xianren Cave (Xichou County), and Lagynochthoniusdaidaiensissp. nov. from Daidai Cave (Qiubei County). All three species are endemic to Yunnan. Tyrannochthoniuscalvatussp. nov., lacking the carapaceal antero-median setae and having intercalary teeth on the movable chelal finger only, is a peculiar chthoniid species.


Introduction
The genus Tyrannochthonius Chamberlin, 1929 contains 149 species and two subspecies, with at least 58 species occurring in caves, and is distributed in all continents except Antarctica (Li 2022;WPC 2022). This genus can be diagnosed as follows: trichobothrium sb situated midway between st and b, or closer to st; trichobothria ib and isb situated close together in a median or sub-basal position on the dorsum of the chelal hand; chelal hand not distally constricted and the movable finger without a complex or strongly sclerotized apodeme at the base; fixed finger usually with one large, medial acuminate spine-like seta at its base, but can be reduced or absent in some cavedwelling species; coxal spines generally long and present on coxae II only; epistome pointed, triangular or rounded, inconspicuous and usually with two closely-flanking setae at its base (Chamberlin 1962;Muchmore 1984Muchmore , 1991Muchmore and Chamberlin 1995;Edward and Harvey 2008). So far, 15 species and one subspecies of this genus have been described from China, of which 12 are exclusively known from karst caves (Mahnert 2009;Gao et al. 2018Gao et al. , 2020Hou et al. 2022a;Li 2022;WPC 2022).
The genus Lagynochthonius Beier, 1951 was erected by Beier (1951) as a subgenus of Tyrannochthonius but was later elevated to generic status by Chamberlin (1962). The genus is diagnosed by trichobothrium sb situated midway between st and b, or closer to st; trichobothria ib and isb situated close together in a median or sub-basal position on the dorsum of the chelal hand; coxal spines generally long and present on coxae II only; chelal hand distally constricted (or flask-shaped) and movable finger with complex or strongly sclerotized apodeme at its base and the modified tooth (td) of the fixed chelal finger displaced onto the dorso-antiaxial face (Chamberlin 1962;Harvey 1989;Muchmore 1991;Judson 2007;Edward and Harvey 2008). At present, this genus contains 67 species (19 species living in caves) distributed in Asia, Australia, Africa, and America. Twenty species of this genus have been described from China, 13 of which are exclusively known from karst caves (Li et al. 2019;Hou et al. 2022a, b;WPC 2022).
Yunnan, located in southwest China, was once an ancient shallow sea during the Sinian (= Ediacaran) to Triassic periods and the area is characterized by massive karst landforms today (11.09 × 10 4 km 2 ) (Wang 2001). The influence of subtropical and tropical monsoon climates as well as the presence of rivers and precipitation regimes have probably fostered the development of karst caves. According to a survey, more than 1000 karst caves have been found in Yunnan Province (Ming 1997). To date, more than 750 cave-dwelling animals have been identified in China (nearly 15% of them are from Yunnan), including 54 cave-dwelling pseudoscorpion species (25 of them are from Yunnan) (Schawaller 1995;Mahnert 2003Mahnert , 2009Mahnert and Li 2016;Gao et al. 2017Gao et al. , 2018Gao et al. , 2020Li et al. 2017Li et al. , 2019Feng et al. 2019Feng et al. , 2020Latella 2019;Zhang et al. 2020;Li and Wang 2021;Hou et al. 2022a, b;Li 2022;WPC 2022;Xu et al. 2022).
Three new cavernicolous species of Chthoniidae have been recently found from the karst caves survey in Yunnan in 2021 and are here described.

Materials and methods
The specimens examined for this study were cleared with a fine, soft-bristle brush and preserved in 75% alcohol and deposited in the Museum of Hebei University (MHBU) (Baoding, China) and the Museum of Southwest University (MSWU) (Chongqing, China). Photographs, drawings, and measurements were taken using a Leica M205A stereo-microscope equipped with a Leica DFC550 camera and the Inkscape software (v. 1.0.2.0). Detailed examination was carried out with an Olympus BX53 general optical microscope. All images were edited and formatted using Adobe Photoshop 2022.
Terminology and measurements follow Chamberlin (1931) with some minor modifications to the terminology of trichobothria (Harvey 1992;Judson 2007) and chelicera (Judson 2007). The chela and legs are measured in lateral view and others are taken in dorsal view. All measurements are given in mm unless noted otherwise. Proportions and measurements of chelicerae, carapace and pedipalps correspond to length/breadth, and those of legs, chela, and hand to length/depth.
Etymology. The specific name is derived from the Latin adjective calvatus (bald) and refers to the absence of two antero-median setae on the carapace.

Tyrannochthonius capito
Etymology. The specific name is derived from the Latin noun capito (big head) and refers to the presence of a large cephalothorax.
Tyrannochthonius capito sp. nov. can be easily distinguished from other Chinese cavedwelling Tyrannochthonius species by the presence of a pair of anterior corneate eyes.
Distribution. Known only from the type locality. Moderately sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin, finely denticulated, epistome pointed and small, triangular; posterior margin of carapace with two setae; tergites I-IV each with two setae. Pedipalps slender, femur 7.79-8.07× longer than broad; chela 7.67-8.39× longer than deep; both chelal fingers without intercalary teeth but fixed chelal finger with a modified accessory tooth (td) on dorso-antiaxial face.