Corresponding author: Rodrigo Lopes Ferreira (
Academic editor: A.S.P.S. Reboleira
Viana ACM, Ferreira RL (2021) A new troglobitic species of
In East Asia, the pseudoscorpion family
During an expedition to caves in Japan (carried out from September 5 to 15, 2017), a single pseudoscorpion was found, belonging to a new species herein described. The single male specimen belonging to the subgenus
It is important to point out that the subgeneric division of the genus
Fieldwork was carried out in September 2017 at Hiura-do Cave, a limestone cave located in the municipality of Kumakogen, Ehime Prefecture, Shikoku Island, Japan (Figs
More details on habitat are covered in a separate section (habitat and threats) later in the paper.
Map of distribution of the representatives of the subgenus
In order to properly observe taxonomic characters, the specimen and its dissected appendages were mounted in temporary cavity slides, using glycerin as medium. Photographs and measurements of body parts were taken with a Zeiss Axio Zoom.V16 stereomicroscope, using the software Zen 2.3. Drawings were prepared with a drawing tube on a Leica DM750 microscope equipped with phase contrast. For drawings, Kaiser’s glycerol gelatin was used instead of glycerin. This mounting media solidifies at cold temperatures, thus allowing the dissected body parts to be kept in a fixed position.
Description of coloration was based on photographs of the living specimen, which were taken with a Cannon SX50 camera. The terminology used in the description follows
Abbreviations used: For trichobothria:
The specific name is given in honor of Dr. Kazunori Yoshizawa, not only due to the assistance provided during fieldwork in Japanese caves, but also to his great contribution to the knowledge of arthropods, especially
Differing from the other members of subgenus
1 | Four eyes well-developed, mostly free-living species |
Subgenus |
– | Eyes completely absent or two rudimentary eyes, mostly cave-dwelling species |
Subgenus |
1 | Two rudimentary eyes present |
|
– | Eyes absent |
|
2 | Palpal femur stout, 3.9 times longer than broad |
|
– | Palpal femur slender, 3.9–6.5 times longer than broad |
|
3 | Cheliceral palm with 6 setae, rallum with 11 blades |
|
– | Cheliceral palm with 5 setae, rallum with 10 blades |
|
4 | Chelal fingers distinctly curved, fixed finger with 9 marginal teeth, movable finger with 11 marginal teeth |
|
– | Fixed chelal fingers not so curved, with 13–17 marginal teeth |
|
5 | Anterior margin of carapace with 10 setae |
|
– | Anterior margin of carapace with 8 setae |
|
6 | Chelal fingers with 13–14 marginal teeth; cheliceral movable finger with about 13 minute teeth |
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– | Chelal fingers with about 16 marginal teeth; cheliceral movable finger with about 18 minute teeth |
|
7 | Body length 1.51–1.97 mm |
|
– | Body length 2.31–2.38 mm |
|
8 | Carapace chaetotaxy 8–2, 24 |
|
– | Carapace chaetotaxy 8–2, 18 |
|
Hiura-do Cave is a limestone cave with approximately 160 meters of horizontal extent and two entrances (Fig.
Type locality and habitat of
Potential prey for the pseudoscorpion are mainly springtails (
The cave presents obvious signs of human visitation (there is an iron ladder installed from the upper to the lower level), but such visitors seem to be mostly speleologists, so no severe impacts were observed in the cave. The external environment is also well preserved, with a forest covering most of the landscape. Considering the well-preserved status of both the cave and the external landscape surrounding the cave, the species seems not to be seriously threatened at the moment.
Concerning
Nonetheless,
Furthermore, although it may simply represent a dispersal-aiding trait, the considerably high level of chelal finger curvature could potentially represent a troglomorphism for the cave-dwelling species in the subgenus. When comparing the chelal fingers of hypogean species and the single epigean representative,
We note some inconsistencies in the measurements and ratios in the descriptions of
With regard to the subgenus
Even when taking into account that
We thank the team of the Center of Studies on Subterranean Biology (especially Dr. Marconi Souza Silva), for help with field work; Dr. Marconi Souza Silva, for producing the distribution map; Yusuke Hara, Dr. Tadashi Komatsu and Dr. Kazunori Yoshizawa for the assistance given during the expedition, and the institutions that supported the study with funding for scholarships and infrastructure (FAPEMIG and VALE). The field trip in Japan was supported by JSPS research grant 15H04409 to KY. RLF is also grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico for financial support (CNPq grant n° 308334/2018-3). We also thank Dr. Mark Harvey, M. Sc. Charles D. R. Stephen and the anonymous reviewer, whose constructive comments and suggestions greatly improved the quality of this paper.
modified from Morikawa 1960.