Two new spider species (Aranei) from the Cis-Urals Steppe, Russia

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Over the last two decades, the spider fauna of the Cis-Urals steppe has been the subject of intensive taxonomic and faunistic studies (Esyunin et al., 1999, 2007, 2019, 2023; Esyunin, Tuneva, 2002, 2020; Tuneva, Esyunin, 2002, 2003; Esyunin, Vlasov, 2021; Vlasov, 2022). As a result of these studies, 14 spider species belonging to six families have been described (Esyunin, Tuneva, 2002, 2020; Tuneva, Esyunin, 2002, 2003; Esyunin, Sozontov, 2016; Esyunin, Efimik, 2022; Esyunin et al., 2023а). Yet, two more new species of Gnaphosidae and Linyphiidae have been discovered in new materials collected during a short 2021 expedition to the Orenburg Reserve. The aim of the present paper is to diagnose and describe both new species.

The spiders reported in this paper were collected by the first author during his fieldtrip to the Burtinskaya steppe site of the Orenburg State Nature Reserve in May 2021. The types are deposited in the Zoological Museum of the Moscow State University, Moscow, Russia (ZMMU; curator K. G. Mikhailov) and the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia (ZISP, curator D. V. Logunov). Stacks of colour images were manually generated using an Olympus OMD EM-10 digital camera, with a Panasonic Lumix H-H025 25 mm f/1.7 lens mounted on a Zeiss microscope. Digital images were prepared by means of the Photoshop CS6 image stacking software. SEM micrographs were made by means of Hitachi TM3000 SEM microscope with back-scattered electrons at the Perm State University. The distribution maps were generated using the online mapping software SimpleMappr (Shorthouse, 2010). The terminology of palp morphology follows Senglet (2004) for Drassylus Chamberlin 1922 and Merrett (1963), with additions according to Bosmans and De Smet (1993) for Walckenaeria Blackwall 1833. The chaetotaxy system for Linyphiidae follows Tanasevitch (2011) and is given as follows: dorsal–prolateral–retrolateral–ventral (a variation, if any). Abbreviations used in the text: AER – anterior row of eyes; ALE – anterior lateral eye, AME – anterior median eye, PER – posterior row of eyes; PLE – posterior lateral eye, PME – posterior median eye. In the following descriptions, leg podomeres are abbreviated as follows: Fm – femur, Pt – patella, Tb – tibia, Mt – metatarsus, Tr – tarsus; leg spination: a – apical, d – dorsal, pl and rl – pro- and retrolateral, v – ventral. The sequence of leg segment measurements is as follows: total length (Fm, Pt, Tb, Mt, Tr). All measurements are in millimeters.

Drassyllus borlynensis Esyunin, Vlasov et Ustinova sp. n.

(Figs 1A‒1D, 2B‒1E)

Material. Holotype, ♂ (ZMMU), Russia, Orenburg Region, Belyaevskiy District, Burtinskaya steppe site of Orenburg State Nature Reserve (51°13ʹ33ʺN, 56°04ʹ28ʺE), stony saline land, pitfall-traps, 30.04– 09.05.2021, S. L. Esyunin.

Diagnosis. In having the pointed tip of the terminal apophysis and the embolus slightly curved terminally, Drassyllus borlynensis sp. n. is most similar to D. praeficus (L. Koch 1866) and D. villicoides (Giltay 1932), but can be distinguished from both by the almost straight retrolateral tibial apophysis (vs. retrolateral tibial apophysis bent dorsad: slightly in D. praeficus (Fig. 2F) and strongly in D. villicoides (Senglet, 2012: fig. 15)), and yellow-brown carapace (vs. dark brown in D. praeficus and D. villicoides). Besides, the new species is notably smaller; its total length – 3.7, compared to 5.0‒6.7 in D. praeficus (Nentwig et al., 2024) and 5.0 in D. villicoides (Senglet, 2012).

Fig. 1. Palp and body of Drassyllus borlynensis sp. n. (A–D) and D. fragilis Ponomarev 2008 (E; holotype from Atyrau Region of Kazakhstan): A, B – right palp, ventral and lateral views, respectively; C, D – carapace and abdomen, dorsal views; E – body, dorsal view. Scale bars, mm: A, B – 0.1, C–E – 1.0.

Description. Holotype male. Small; total length 3.7. Carapace yellow-brown, 1.6 long, 1.3 wide (Fig. 1C). Chelicerae brown. Labium and maxillae brown, with white tips. Sternum dark brown. Legs dark brown except for yellow tarsi and metatarsi (Fig. 1C). Clypeal height 0.05. Chelicera 0.40 long. Abdomen black, 2.1 long, 1.2 wide. Scutum trapezoid covering one third of abdominal dorsum (Fig. 1D). Eye sizes and interdistances: AER0.29, PER0.36, AME0.04, ALE (oval) 0.07×0.08, PLE (oval) 0.06×0.07, PME (oval) 0.08×0.07; eyes field trapezoid: length 0.17, width 0.14 anteriorly and 0.20 posteriorly; ALE-AME0.01, AME-AME0.04, PLE-PME0.03, PME-PME0.03. All eyes light. Leg formula IV>I>II>III. Leg measurements: I 4.10 (1.13, 1.53, 0.75, 0.70), II 3.58 (0.98, 1.33, 0.68, 0.60), III 3.05 (0.88, 0.95, 0.70, 0.53), IV 4.45 (1.20, 1.55, 1.00, 0.70). Leg spination: Fm I d1–1–0, pl0–0–1; II d1–1–0, pl0–0–1; III d1–1–0, pl0–1–1, rl0–1–1; IV d1–1–0, pl0–1–1, rl0–1–1. Tb III pl1–0–1, rl1–0–1, v2–2–2; IV pl and rl1–0–1, v2–2–2. Mt I v2–2–2; II v2–2–2; III d0–1–0, pl1–1–2, rl1–1–2, v2–0–0; IV d1–0–1, pl1–2–1, rl1–2–1, v1–0–0. Tibial apophysis almost straight (Fig. 2E), ca 0.4 of cymbium length. Terminal apophysis (TA) with its tip pointed retrolaterally (Figs 1A, 2B, 2C). Projection of embolar radix (RP) robust, tapering (Figs 1A, 2B). Embolus filiform and long, starting at the mid-point of tegulum retrolaterally and bent terminally (Figs 1A, 1B; 2B, 2D).

F e m a l e unknown.

Etymology. The species name comes from the Kazakh word “Борлы” (Borly – chalky), from which the Russian name “Burtinskaya steppe” has derived.

Fig. 2. Male palp of Drassyllus praeficus (L. Koch 1866) (A, F) and D. borlynensis sp. n. (B–E), scanning electron micrographs: A, B – palp, ventral views; C, D – palp, lateral-ventral and lateral views, respectively; E, F – palpal tibia, lateral views; Em – embolus, ER – embolar radix, RP – embolar radix projection, TA – terminal apophysis. Scale bar 0.1 mm.

Remarks. Drassyllus is a comparatively large genus of the ground spiders, with 91 valid species having been known from the Holarctic (WSC, 2024), most of which occur in the Nearctic and some 30 in the Palaearctic. Only 18 species are known to occur in the West Palaearctic (Nentwig et al., 2024). Two of them, D. covid Chatzaki 2021 and D. fragilis Ponomarev 2008, are known from females only. Both are of the same size class as the new species: D. covid – 4.1 (Chatzaki, 2021), D. fragilis – 3.6 (Ponomarev, 2008). However, in our opinion, they are not conspecific to the new species. D. covid appear to be a regional endemic of the Mediterranean, whereas D. fragilis, which was described from the Atyrau Region of Kazakhstan, differs from the new species in uniformly yellow body and leg colouration (Fig. 1E).

Walckenaeria danismani Esyunin, Vlasov et Ustinova sp. n. (Figs 3, 4)

Walckenaeria corniculans: Danışman et al., 2020, p. 21, figs 11, 12 (♂♀; misidentification) nec O. Pickard-Cambridge, 1875.

Material. Holotype, ♂ (ZMMU), Russia, Orenburg Region, Belyaevskiy District, Burtinskaya steppe site of Orenburg State Nature Reserve (51°13ʹ33ʺN, 56°04ʹ28ʺE), Festuca-Stipa steppe, 04.05.2021, S. L. Esyunin. Paratypes: 1♂ (ZISP, ARA_ARA_0001538), same locality, multi-herbaceous steppe, 07.05.2021, S. L. Esyunin; 1♂ (ZMMU), same locality, reed grass (Calamagrostis) steppe association, in litter, 5.05.2021, S. L. Esyunin.

Diagnosis. Walckenaeria danismani sp. n. belongs to the subgenus Prosopotheca Simon 1884 (sensu Wunderlich (1972)). Males of this group are characterized by the following characters: (1) cephalic elevation absent, (2) undivided cone-shaped tubercle and/or bristle tufts (clubbed or pinnate) in front of PME, (3) embolus making almost a complete revolution, and (4) tibial apophysis complex, with many apophyses.

In having a cone-shaped tubercle on the ocular field, the embolus tapering towards its tip and the bifurcate apex of distal tibial apophysis, males of the new species are similar to the West Palaearctic W. baborensis Bosmans 1993, W. corniculans (O. Pickard-Cambridge 1875), W. erythrina (Simon 1884), W. mariannae Bosmans 1993, and the West-Central Palaearctic W. monoceros (Wider 1834).

Two species, viz. Walckenaeria danismani sp. n. and W. baborensis, differ from the remaning four species in the shape of the distal tibial apophysis: viz., the anterior-retrolateral (AAR) and anterior (AA) apophyses are short and strongly curved in W. corniculans, W. erythrina and W. mariannae (e. g., see fig. 285 in Wiehle (1960); fig. 40 in Wunderlich (1972) and figs 33‒34 in Bosmans, De Smet (1993), respectively) or short and very narrow in W. monoceros (Wunderlich, 1972: fig. 43), vs. AAR and AA elongated (approximately equal to the width of the distal tibial apophysis) in new species (Figs 3C, 3D; 4C) and W. baborensis. The new species can be easily distinguished from W. baborensis by the embolic shape: embolus thin, bending backwards in an arc towards the radix in W. danismani sp. n. (Figs 3B; 4A, 4B) vs. comparatively thicker, running parallel to the radix and directed forwards in W. baborensis (Bosmans, De Smett, 1993: fig. 20).

Females of the aforementioned group of closely related species have a very similar epigyne morphology and, unfortunately, the available illustrations (e. g., figs 12A, 12C in Danışman et al. (2020)) do not allow us to draw any reasoned conclusion.

Description. Male holotype. Total length 2.3. Carapace dark brown in middle part, yellow-brown along margins and on clypeus; 1.05 long, 0.70 wide. Carapace modified: cephalic part slightly elevated and projecting forwards over clypeus; there is a small conical elevation carrying crest of clavate setae in front of posterior median eyes (Figs 3E, 4E). Chelicerae brown, 0.35 long, unmodified. Labium black, with a distal-apical white swelling; endites yellow. Legs yellow. Leg I 2.93 (0.77, 0.25, 0.87, 0.60, 0.43), IV 2.99 (0.80, 0.24, 0.78, 0.73, 0.43) long. Chaetotaxy: 2.2.1.1, spines thick, distal spines poorly visible. Tm I 0.53. Metatarsus IV with trichobothrium. Abdomen black, 1.3 long, 0.8 wide.

Fig. 3. Carapace and details of male palp structure of Walckenaeria danismani sp. n.: A – bulbus, ventral view; B – right palp, retrolateral view; C, D – palpal tibia, dorsal and ventral views, respectively; E – carapace, lateral view. Scale bar 0.1 mm.

Palp as in Figs 3A–3D, 4A–4D. Tibia with apophyses that are typical of the subgenus; anterior (AA) and retrolateral apophyses (AAR) arms narrow and rounded, median retrolateral apophysis (AMR) tooth-like (Figs 3C, 3D; 4C). Drop-shaped radix (R), with long S-shaped radix part (RP); embolus relatively short, bending backwards in an arc towards radix and tapering towards its tip (Figs 3B; 4A, 4B); paracymbium L-shaped without setae; tegulum with a frontal round protrusion; distal suprategular apophysis (SA) long, narrow (Figs 3B, 4B).

Variation. Carapace and sternum brown in the paratypes or «reddish orange» in Turkish specimen (Danışman et al., 2020).

Female. See Danışman et al. (2020: 21).

Etymology. The species is dedicated to Dr Tarık Danışman (Kırıkkale, Turkey), who has undertaken important arachnology research in Turkey.

Fig. 4. Male palp of Walckenaeria danismani sp. n., scanning electron micrographs: A, D – palp, lateral views; B – same, ventral view; C – palpal tibia, dorsal view; D – bulbus, anterior view; E – carapace, lateral view (D, E after Danışman et al. (2020)); AA – anterior arm of distal apophysis, AAR – antero-retrolateral arm of distal apophysis, AMR – median-retrolateral arm of distal apophysis, Em – embolus, M – median membrane, R – radix, RP – radix part, SA – suprategular apophysis, T – tegulum. Scale bar 0.1 mm.

Remarks. Danışman et al. (2020: 21) recorded W. corniculans from Turkey solely based on the fact that «palpal tibia with complex apophyses» and «epigyne with rectangle-shaped plate». However, the shape of conical elevation of the male head, the shape of retrolateral apophyses, anterior apophyses and the embolus, as well as characters of the epigyne in Turkish specimens, viz., conical elevation small, retrolateral apophyses and anterior apophyses elongated, embolus bends backwards in an arc towards the radix, epigynal plate with straight (not rounded) lateral margins (all these characters are absent in W. corniculans – see, for example, figs 124C‒D, 124G in Locket, Millidge (1953), figs 278‒285 in Wiehle (1960) or figs 33‒35 in Wunderlich (1972)), are evidence that Danışman’s record also belongs to W. danismani sp. n.

Fig. 5. Distribution map with records of Walckenaeria danismani sp. n.: type locality (black dot), literature data (black circles).

The species Walckenaeria cf. corniculans (O. Pickard-Cambridge 1875) was recorded by Piterkina (2009: 341) and Piterkina, Mikhailov (2009: 69) from the Dzhanybek Research Station (Institute of Forestry of the Russian Academy of Sciences) that is situated at the border of Volgograd Region of Russia and West Kazakhstan Region of Kazakhstan (c. 49°25ʹN, 46°51ʹE). The spider was found in a desert habitat (Piterkina, 2009), whereas in Europe W. corniculans demonstrates an affinity to deciduous forests, preferring humid conditions (Nentwig et al., 2024). In our opinion, this record is likely to also refer to the new species described above.

Distribution (Fig. 5). Turkey and semidesert and southern steppe landscapes of the Russian Plain, from Volgograd to Orenburg Regions.

ACKNOWLEDGEMENTS

The authors are grateful to Gulli Sh. Farzalieva (Perm, Russia) and Andrey V. Grischenko (Perm, Russia) for the help with producing some digital photographs and SEM micrographs, respectively. Our cordial thanks go to Andrey V. Tanasevitch (Moscow, Russia) for constructive comments on the manuscript and Kirill G. Mikhailov (Moscow, Russia) who kindly provided us with the photograph of the type specimen of Drassyllus fragilis. Special thanks go to Dmitri V. Logunov (St Petersburg, Russia) for editing the English of the final draft.

FUNDING

This work was supported by ongoing Perm State University funding. No additional grants to carry out or direct this particular research were obtained.

ETHICAL APPROVAL AND CONSENT TO PARTICIPATE

This work does not contain any studies involving living animals. All studied materials was obtained from the zoological collection of the Department of Invertebrate Zoology and Aquatic Ecology, Perm State University (Perm, Russia).

CONFLICT OF INTEREST

The authors of this work declare that they have no conflicts of interest.

About the authors

S. L. Esyunin

Author for correspondence.
Email: eyusnin@mail.ru
Russian Federation, Perm, 614068

S. V. Vlasov

Email: probel15@yandex.ru
Russian Federation, Perm, 614068

A. L. Ustinova

Email: anastasiya-ustinova-98@mail.ru
Russian Federation, Perm, 614068

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2. Fig. 1. Palp and body of Drassyllus borlynensis sp. n. (A–D) and D. fragilis Ponomarev 2008 (E; holotype from Atyrau Region of Kazakhstan): A, B – right palp, ventral and lateral views, respectively; C, D – carapace and abdomen, dorsal views; E – body, dorsal view. Scale bars, mm: A, B – 0.1, C–E – 1.0.

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3. Fig. 2. Male palp of Drassyllus praeficus (L. Koch 1866) (A, F) and D. borlynensis sp. n. (B–E), scanning electron micrographs: A, B – palp, ventral views; C, D – palp, lateral-ventral and lateral views, respectively; E, F – palpal tibia, lateral views; Em – embolus, ER – embolar radix, RP – embolar radix projection, TA – terminal apophysis. Scale bar 0.1 mm.

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4. Fig. 3. Carapace and details of male palp structure of Walckenaeria danismani sp. n.: A – bulbus, ventral view; B – right palp, retrolateral view; C, D – palpal tibia, dorsal and ventral views, respectively; E – carapace, lateral view. Scale bar 0.1 mm.

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5. Fig. 4. Male palp of Walckenaeria danismani sp. n., scanning electron micrographs: A, D – palp, lateral views; B – same, ventral view; C – palpal tibia, dorsal view; D – bulbus, anterior view; E – carapace, lateral view (D, E after Danışman et al. (2020)); AA – anterior arm of distal apophysis, AAR – antero-retrolateral arm of distal apophysis, AMR – median-retrolateral arm of distal apophysis, Em – embolus, M – median membrane, R – radix, RP – radix part, SA – suprategular apophysis, T – tegulum. Scale bar 0.1 mm.

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6. Fig. 5. Distribution map with records of Walckenaeria danismani sp. n.: type locality (black dot), literature data (black circles).

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