Single-specimen study documents first Georgian record of Pselaphochernes scorpioides

A single female pseudoscorpion collected in a Malaise trap in western Georgia provides the first record of Pselaphochernes scorpioides (Hermann, 1804) from the country and the first record of the genus Pselaphochernes in Georgia. The specimen was collected in Kintrishi National Park in the Adjara region on June 1–15, 2018, bringing the number of pseudoscorpion species reported from Georgia to 54. Because the finding is based on one specimen, it documents an occurrence rather than establishing the species’ abundance or distribution across Georgia.

The animal was collected during the Caucasus Barcode of Life project in a temperate deciduous forest at 41°44′38.0″N, 42°05′02.0″E and 1,264 metres above sea level. The sampling site is within Kintrishi National Park, an area containing Colchic relict forests with evergreen understory. Five pseudoscorpion species had previously been recorded there, all in the genus Neobisium.

This was a single-specimen morphological study. The female was cleared in lactic acid and examined as a temporary slide with stereo and compound light microscopes. It was then rinsed in distilled water and preserved in 96% ethanol. Measurements were obtained using Capta Vision software, while the morphological drawings were prepared with Adobe Illustrator. Identification followed published identification keys and descriptions. The voucher specimen is held at the Zoology Department of Ilia State University in Tbilisi under the inventory code ISUIZ-Pseud-243.

The carapace was 1.07 times longer than broad and had a granulated surface with clavate setae, but no eyes or eyespots. Four pairs of lyrifissures were present, including two pairs along the anterior margin and one pair along the posterior margin. The chelicera had a four-branched galea, two branches of which were broken, a serrated exterior with 17 lamellae, five setae on the hand, and a rallum with three blades. The pedipalp femur was 2.66 times longer than broad, while the patella was 1.97 times longer than broad.

The fixed chelal finger carried 45 small cusped teeth and the movable finger carried 37. The fixed finger had seven external and five internal accessory teeth; the movable finger had two external and two internal accessory teeth. The body measured 1.51 millimetres in length, and the chela measured 0.94 millimetres. The female genital atrium contained a T-shaped spermatheca. One long tactile seta was recorded near the middle of the tarsus of leg IV, although the seta was broken and only its base remained visible.

Several characters were used to distinguish Pselaphochernes from the other chernetid genera recorded in Georgia: Allochernes, Chernes, Dendrochernes and Lamprochernes. These characters include the T-shaped spermatheca, a three-bladed rallum, a long medial tactile seta on pedal tarsus IV, and a normal posterolateral corner of coxa IV. The only other Pselaphochernes species known from the Caucasus at the time of the study was P. lacertosus, which has a chelal finger shorter than the chelal hand without its pedicel. The authors noted that the known distribution of P. lacertosus made its occurrence in Georgia possible, but no such specimen was reported in the study.

The Georgian specimen closely matched published descriptions of P. scorpioides, although the authors identified several differences that they considered potentially attributable to intraspecific variation. It had four pairs of carapace lyrifissures, whereas the Iranian specimens described by Nassirkhani had five pairs. Its fixed and movable chelal fingers had seven and five external accessory teeth, compared with eight and six, respectively, in Beier’s redescription. The pedipalpal femur length-to-width ratio was 2.41, lower than the 2.5–2.6 and 2.5–2.83 ranges in those earlier descriptions but within the 2.27–2.95 range reported by Christophoryová and Jablonski.

Published records describe P. scorpioides as occurring across Europe, North Africa, the Middle East and Central Asia, with records from Azerbaijan, Armenia and Turkey in the Caucasus. The species has been collected from heaps of decomposing material, leaf litter, bird and ant nests, dead wood, tree hollows, decaying wood, beneath tree bark and Malaise traps. Phoresy on dipterans has also been observed. The authors identified this behavior as a possible explanation for the capture of the Georgian specimen in a trap primarily used to collect flying insects, but the collection did not establish how the animal entered the trap.

Before this record, 53 pseudoscorpion species in six families had been reported from Georgia: Chernetidae, Atemnidae, Cheliferidae, Neobisiidae, Withiidae and Chthoniidae. The new finding adds P. scorpioides to the nine previously reported chernetid species and introduces the genus Pselaphochernes to the Georgian fauna. The authors concluded that knowledge of the pseudoscorpion fauna of Georgia and the wider Caucasus remains incomplete and stated that further investigation of the Georgian fauna is needed. The study itself is limited by its single specimen and a sampling period of two weeks at one locality, so it does not establish population size, long-term occupancy or the full habitat range of the species in Georgia.

Subject of Research: First Georgian record of the pseudoscorpion Pselaphochernes scorpioides based on one female specimen

Article Title: The first record of Pselaphochernes scorpioides  (Hermann, 1804) from Georgia, Caucasus ( Arachnida : Pseudoscorpiones )

Article References: Gogshelidze, M., & Novák, J. (2023). The first record of Pselaphochernes scorpioides (Hermann, 1804) from Georgia, Caucasus (Arachnida: Pseudoscorpiones). Caucasiana, 2, 299-303. https://doi.org/10.3897/caucasiana.2.e114375

Image Credits: AI Generated

DOI: 10.3897/caucasiana.2.e114375

Keywords: Pselaphochernes scorpioides, Georgia, pseudoscorpions, Chernetidae, Kintrishi National Park, Adjara, malaise trap, morphological identification, faunal record, Caucasus, first, record