The Caucasus ecoregion, straddling the crossroads of Europe and Asia, is recognised as one of the world’s 36 biodiversity hotspots. Yet despite more than 150 years of arachnological research in the region, only around 1,200 spider species are currently recorded across the entire ecoregion. The comparison with European countries of similar or smaller land area at the same latitudinal range is striking: Greece hosts 1,223 species, Italy 1,587, Germany 1,014, Spain 1,414, and France 1,601. Many spider species are capable of dispersing over long distances, which makes the apparent gap in the Caucasus even more puzzling. For decades, Georgia remained one of the least-studied countries in the region, with only 627 species recorded up until 2023, compared to 725 in neighbouring Azerbaijan.

That picture is changing rapidly. A growing number of recent publications, using both classical and integrative taxonomic approaches, have documented new records and species descriptions, pushing the Georgian list to roughly 800 species. As a result, Georgia now holds the leading position in spider species diversity among the countries of the South Caucasus. Notably, non-arachnologists and citizen scientists have played a key role in collecting some of these valuable records. Still, the authors of the new study emphasise that southeastern Georgia in particular requires further active research, and their latest paper delivers exactly that: a new species description alongside a list of new country and regional records spanning four families.

The new species, Tegenaria amirani, was described based on both male and female specimens collected in Georgia. The holotype male was found on 30 June 2024 on the Kvernaki ridge near Gori in the Shida Kartli region, at 705 metres above sea level, on a south-exposed dry rocky slope covered in heathland. Paratypes include a female from the same locality and a male collected on 2 June 2023 near the village of Dighomi in Tbilisi, at 724 metres. All specimens were individually collected under stones from dry and rocky slopes, a habitat preference that inspired the mythological name.

Tegenaria is the most speciose genus of the tribe Tegenariini, currently encompassing 138 valid species, mostly diversified in the Mediterranean region. In its current composition, the genus is probably not monophyletic, meaning its members may not all share a single exclusive common ancestor. To date, 32 species have been recorded in the Caucasus, with two recently described from Armenia and Georgia. The new species belongs to the lyncea species group, defined by Brignoli in 1978, characterised by a hammer-shaped conductor with pronounced prolateral and retrolateral branches on the male palp.

Technically, males of T. amirani are similar to those of T. podoprygorai and T. terskovi, but they can be distinguished by the position of the median apophysis, which sits at roughly the 12 to 1 o’clock position on the tegulum, rather than originating at about 3 o’clock as in the related species. The tip of the conductor has a ventral branch shorter than the dorsal one, the reverse of the condition in T. podoprygorai and T. terskovi, and the retrolateral tibial apophysis is differently shaped. Females resemble those of T. pseudolyncea in the conformation of the epigyne, but differ in having a general sternal pattern rather than a uniformly brown one, terminal receptacula separated by about their own diameter rather than twice that distance, and an overall smaller body size of 5.42 millimetres compared to 7.6 millimetres in T. pseudolyncea.

The male holotype measures 5.35 millimetres in total length, with a carapace 2.61 millimetres long and 1.95 wide. The chelicerae are red-brown, bearing four promarginal and four retromarginal teeth. The carapace is light reddish, with a darker pars cephalica marked by a thin dark median line, while the pars thoracica is lighter with an uneven darker radiating pattern. The legs are yellowish with darker coxae, and the coxae and femora carry ventral dark grey spots. The palpal structure shows a femur roughly 1.6 times longer than the tibia and patella together, a tibia about 1.4 times longer than wide with an apophysis bearing two pointy arms, and a cymbium roughly 1.6 times longer than wide. The embolus is long, originating at about the 6 o’clock position and mostly hidden under the conductor flap.

Beyond the new species, the study reports several first records for Georgia. Tegenaria hasperi, an Agelenidae previously known from France east to Dagestan, is documented for the first time in Georgia and the South Caucasus, based on specimens from the Kumisi Reservoir vicinity and the Lisi Lake area near Tbilisi. Archaraeoncus prospiciens and Trichoncoides piscator, both Linyphiidae collected by flagging vegetation in the steppe near Udabno village in Kakheti, are new to Georgia, with the former also representing the first record of its genus in the country. Aulonia kratochvili, a wolf spider distributed from Greece to western Turkmenistan, is recorded in Georgia for the first time from the Iori River floodplain, and this northernmost record of its range extends knowledge of its distribution.

Two additional records carry regional significance. Echemus levyi, a small light-coloured gnaphosid previously known only from Cyprus, Greece and Central Turkey, is reported for the first time in the Caucasus region, and the northernmost record of its distribution, based on specimens found in a Tbilisi apartment and on a building wall in the Vake district. Marinarozelotes malkini, a gnaphosid distributed from the eastern Mediterranean east to western Kazakhstan, is recorded in the South Caucasus for only the second time, from steppe habitats near Lisi Lake and the Rustavi Car Market, marking the southernmost record in the region. Tegenaria pseudolyncea, previously documented in Georgia only from the Samachablo and Imereti regions, is now recorded in Guria for the first time, found under construction material in a village in western Georgia.

The methodology behind these findings reflects a blend of classical and modern techniques. Specimens were preserved in 96 percent ethanol and stored at minus 22 degrees Celsius in the scientific collections of Ilia State University in Tbilisi. Identification was carried out using literature sources on Caucasian spiders as well as current databases. Spiders were examined and measured under a Zeiss Stemi 508 stereo microscope with 8:1 zoom, and drawings were made digitally using a Wacom pen tablet with Krita and Photoshop. Specimens were photographed with a Canon EOS 90D camera paired with a macro lens and a twin flash system, with digital images stacked using Zerene Stacker software. The female epigyne and endogyne were prepared using a 10 percent potassium hydroxide solution, allowing detailed study of the internal reproductive structures that are critical for species-level diagnosis. In total, 28 spiders comprising 16 males and 12 females were examined, representing seven species from five genera and four families, a modest sample size that nonetheless yielded a new species and multiple significant range extensions, underscoring how much remains to be discovered in the Caucasus.

Subject of Research: Biology

Article Title: New data on spiders ( Arthropoda , Arachnida , Araneae ) of Georgia with description of a new species from Tegenaria lyncea group

Article References: Seropian, A., Ninua, L., Rostiashvili, I., Bulbulashvili, N., & Makharadze, G. (2025). New data on spiders (Arthropoda, Arachnida, Araneae) of Georgia with description of a new species from Tegenaria lyncea group. Caucasiana, 4, 65-80. https://doi.org/10.3897/caucasiana.4.e162490

Image Credits: AI Generated

DOI: 10.3897/caucasiana.4.e162490

Keywords: data, spiders, Arthropoda, Arachnida, Araneae, Georgia, description, species, Tegenaria, lyncea, group, scientific research