﻿Three new species of dragon pseudoscorpions (Pseudoscorpiones, Pseudotyrannochthoniidae) from China

﻿Abstract Three new pseudoscorpions in the family Pseudotyrannochthoniidae are described from China: Allochthoniushispidussp. nov. from Chongqing (Wushan County), Spelaeochthoniushuanglaoensissp. nov. from Beijing (Fangshan District), and Spelaeochthoniustuoliangensissp. nov. from Hebei (Pingshan County). Detailed diagnoses and illustrations of all new species are provided.


Introduction
The monophyletic pseudoscorpion family Pseudotyrannochthoniidae Beier, 1932, originated in East Asia during the Middle Triassic (Harms et al. 2024) and is one of the earliest branches of pseudoscorpion families.The group is small-bodied, usually less than 3 mm, but the chelicerae are disproportionately large and resemble the jaws of the mythical dragon.Consequently, its group has earned the colloquial name dragon pseudoscorpions (Harms et al. 2024).Members of the family can be distinguished from all other pseudoscorpions in having trichobothria ib and isb located at the base of the fixed chelal finger and coxal spines present only on coxae I (Harms and Harvey 2013).Pseudotyrannochthoniidae are distributed on all continents except Antarctica and inhabit leaf litter and caves (You et al. 2022;Gao et al. 2023).Niche modeling suggests that the distribution of pseudotyrannochthoniids is determined by the interaction of constantly moderate temperatures and high moisture availability, a pattern that is globally repeated (Harms 2018;Harms et al. 2019).To date, this group comprises 80 described species in six genera.Throughout Asia, pseudotyrannochthoniids are represented by three genera, Allochthonius Chamberlin, 1929, Centrochthonius Beier, 1931, and Spelaeochthonius Morikawa, 1954, and all extant species in these three genera are narrow-range endemics (Fig. 1; WPC 2024).
The genus Spelaeochthonius, currently found only in East Asia, includes 11 described species.It can be distinguished from other pseudotyrannochthoniid genera by the number of carapaceal setae (only 16), the number, shape, and arrangement of the coxal spines (never on a common protuberance and more than seven blades that are longer and distally pinnate or serrate), and the shape of the intercoxal tubercle (bisetose and generally smaller than that of Allochthonius) (Morikawa 1956;You et al. 2022).The genus consists exclusively of subterranean species with strongly troglobitic habitus occurring in China (two species), South Korea (three species), and Japan (six species) (WPC 2024).
This study describes three new pseudotyrannochthoniid species from both the surface and subterranean environments.Detailed diagnoses, descriptions, and illustrations are provided for each species.Two of these species are placed in Spelaeochthonius, while one is assigned to Allochthonius.Additionally, a distribution map of all Chinese pseudotyrannochthoniid species is given.

Materials and methods
The specimens examined for this study are 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 stereomicroscope equipped with a Leica DFC550 camera.Detailed examination was carried out under an Olympus BX53 upright microscope.Scanning electron microscopy (SEM) was done under high vacuum with a JEOL JSM-IT500 after critical-point drying and gold-palladium coating.The distribution map was made using ArcGIS v. 10.6 (Fig. 1).All images were edited and formatted using Inkscape v. 1.0.2.0 and Adobe Photoshop 2022.
Etymology.The specific name is derived from the Latin word hispidus (hirsute, hairy), which refers to the presence of abundant setae on the chela, palpal femur, and patella.

Spelaeochthonius tuoliangensis
Etymology.This species is named after its type locality, Tuoliang National Nature Reserve.

Discussion
The morphology of the coxal spines is an important diagnostic feature that allows to distinguish the two Asian endemic genera: Centrochthonius and Spelaeochthonius (Harvey and Harms 2022;You et al. 2022).In general, Centrochthonius shows a unique arrangement of fewer than six coxal blades that are short, tripartite, and distally acute (Gao et al. 2016;Harvey and Harms 2022;Schwarze et al. 2022).In contrast, Spelaeochthonius is characterized by having more than seven coxal blades that are longer and distally plumose or terminate as a feathered tassel (Morikawa 1954;You et al. 2022).The two new species of Spelaeochthonius described in this study, along with the previously described S. wulibeiensis, exhibit typical characters of the genus Spelaeochthonius, although with atypical coxal spines that are longer and distally spatulate (Figs 8A, 11A, B;Gao et al. 2023).In addition, the diversity of coxal spine morphology within Spelaeochthonius is notable, as seen in S. undecimclavatus Morikawa, 1956, where the spines are club-shaped rather than distally plumose (Morikawa 1956).Therefore, it is appropriate to place these two new species in the genus Spelaeochthonius, and it may be assumed that the species exhibiting these atypical spines are endemic to China.These atypical spines are similar to those found in the three North American species classified as "Pseudotyrannochthonius" and forming a monophyletic sister group to Spelaeochthonius (Harms et al. 2024); these are all characterized by tripartite spines with spatulate tips.However, the intermediate rami of these atypical spines are notably elongated (Muchmore 1967;Benedict and Malcolm 1970).
All 11 currently known Spelaeochthonius species are exclusively found within caves and are completely blind (WPC 2024).Spelaeochthonius tuoliangensis sp.nov.represents the first epigean species of this genus with small eye spots (Fig. 9C).While most China's karst landforms are distributed in the southern subtropical regions, there are also a few karst caves located in temperate regions (Liu et al. 2020).Due to Pleistocene glaciation, caves served as refugia for troglobites, like S. huanglaoensis sp.nov., while their surface counterparts would have normally gone extinct under adverse climatic conditions (Holsinger 2000).Spelaeochthonius tuoliangensis sp.nov.may be the remnant of a former surface fauna of Spelaeochthonius that is now largely extinct in eastern Asia but remains highly diverse in subterranean habitats.The discovery of two new Spelaeochthonius species further extends the geographic range of the genus in East Asia.In contrast, the genus Allochthonius, which is also endemic to East Asia, is more widely distributed; the discovery of Allochthonius in Baltic amber from Europe (Schwarze et al. 2022) indicates a previously wider distribution of this genus.The larger population and perhaps greater adaptability of Allochthonius have allowed this genus to occupy a wider range of ecological niches.
The research on the family Pseudotyrannochthoniidae is still in its infancy in China, with 21 species recorded thus far (Fig. 1; WPC 2024), mostly concentrated in Yunnan and Guizhou provinces of southwestern China.More investigations are needed in northern and central China to explore the geographic range of this family.However, our fieldwork has revealed that these small arachnids have very low abundance, are endemic to small areas (some are confined to a single cave), are vulnerable to environmental changes, and are easily overlooked.Therefore, it is extremely important to protect their habitat while investigating.

Figure 4 .
Figure 4. Allochthonius hispidus sp.nov., holotype male A carapace (dorsal view) B left chelicera (dorsal view), with details of teeth C coxal spines on coxae I (ventral view) D rallum E left chela (lateral view), with details of trichobothrial pattern F left pedipalp (minus chela, dorsal view) G left chela (dorsal view) H leg I (lateral view) I leg IV (lateral view).Scale bars: 0.20 mm.

Figure 7 .
Figure 7. Spelaeochthonius huanglaoensis sp.nov., holotype male A carapace (dorsal view) B left chelicera (dorsal view), with details of teeth C rallum D left chela (lateral view), with details of trichobothrial pattern E left pedipalp (minus chela, dorsal view) F left chela (dorsal view) G leg I (lateral view) H leg IV (lateral view).Scale bars: 0.20 mm.

Figure 10 .
Figure 10.Spelaeochthonius tuoliangensis sp.nov., holotype female A carapace (dorsal view) B left chelicera (dorsal view), with details of teeth C rallum D left chela (lateral view), with details of trichobothrial pattern E left pedipalp (minus chela, dorsal view) F left chela (dorsal view) G leg I (lateral view) H leg IV (lateral view).Scale bars: 0.20 mm.