Bisetifer tactus, Nadolny & Turbanov, 2025

Nadolny, Anton A. & Turbanov, Ilya S., 2025, A review of cave spiders (Arachnida, Araneae) of the Crimean Mountains, with descriptions of two new species, ZooKeys 1230, pp. 37-80 : 37-80

Bisetifer tactus sp. nov.

Figs 6 E, F , 7 , 8 , 9

Type material.

Holotype • ♂ ( ZMMU Ta-8255 ), Crimea, nr Sevastopol, Tshernaya River canyon, Tshernoretshenskaya Cave , 3. III. 2018, I. S. Turbanov leg. Paratypes • 3 ♀♀ ( ZMMU Ta-8256 ), 5. V. 2017 • 1 ♀ ( TNU 10235 ), 4. V. 2018, same cave and collector as for a holotype .

Diagnosis.

Bisetifer tactus sp. nov. has reduced eyes (Figs 7 A – F , 8 A – D ) (vs other congeners, B. cephalotus and B. gruzin , have well developed eyes, see Tanasevitch et al. 2015: figs 1–6). Additionally, B. tactus sp. nov. differs from its congeners in having: 1) the embolus hidden between radix and distal suprategular apophysis (Figs 8 G, H , 9 A, C, D ) (vs not hidden, well visible, see Tanasevitch et al. 2015: figs 7, 19); 2) the hook-shaped and pointed apical part of radix (Figs 8 G , 9 C ) (vs conical in B. cephalotus and flat in B. gruzin , see Tanasevitch et al. 2015: figs 9, 14, 23, 28–29); 3) the distal suprategular apophysis without a complicated arrangement of apophyses, with barbs on its edge (Figs 8 G , 9 A, C, D ) (vs with apophyses, without barbs, see Tanasevitch et al. 2015: figs 7, 19); 4) the oval posterior edge of epigyne (Figs 6 E , 9 E ) (vs with nipple-shaped outgrowths in B. cephalotus , with bow-shaped outgrowths in B. gruzin , see Fig. 6 B, C and Tanasevitch et al. 2015: figs 17, 30).

Description.

Male. Total length 1.5. Carapace 0.63 long, 0.5 wide, pale brown; modified as in Figs 7 D, E , 8 C, D : head part conical, with setae. Eyes reduced, almost completely disappeared (head part with small pale spots, visible under light microscope; no lens visible under SEM). Chelicerae 0.31, brownish, transverse shallow cuticular grooves throughout the basal segment. Legs pale brown, chaetotaxy 2.2.1.1, metatarsi I – IV spineless, metatarsi IV without trichobothrium, TmI 0.35, leg I 2.47 long (0.69 + 0.18 + 0.63 + 0.52 + 0.45), leg IV 2.53 long (0.71 + 0.17 + 0.69 + 0.54 + 0.42). Palp as in Figs 8 F – I , 9 A – D : tibia with a ventro-retrolateral apophysis and two large setae on its tip, distally setae poorly serrate; paracymbium L-shaped; distal suprategular apophysis – flat, curved, and pointed, with barbs on its anterior edge; embolus small, situated in a cavity between distal suprategular apophysis and radix; apical part of radix hook-shaped and pointed distally, well-sclerotised process, retrolaterally with membrane. Abdomen pale grey.

Female. Total length 1.58. Carapace 0.77 long, 0.59 wide; unmodified. Eyes reduced, almost completely disappeared (head part with small pale spots, clearly visible under light microscope; a few poorly developed lenses visible under SEM). Chelicerae 0.36, transverse shallow cuticular grooves throughout the basal segment. TmI 0.44. Leg I 2.64 long (0.73 + 0.21 + 0.7 + 0.54 + 0.46), leg IV 2.78 long (0.8 + 0.2 + 0.77 + 0.59 + 0.42). Body colouration and spination as in the male. Epigyne as in Figs 6 E, F , 9 E – G : epigynal plate oval, with lateral outgrowths in which copulatory ducts open; spermathecae consists of two parts: base with copulatory duct and head with receptacle and fertilisation duct; cavity of receptacle subdivided on ventral and dorsal parts.

Variation.

Females (n = 3): carapace width 0.53–0.59; femur I length 0.69–0.73.

Distribution and records from the Crimean caves.

Map (Fig. 17 B – purple circle). Only known from the type locality: Tshernoretshenskaya Cave, nr Sevastopol.

Ecology.

The species has troglomorphic characteristics related to the subterranean habitat, such as the pale body and reduced eyes. Based on the morphological features and the fact that this species is known only from caves, it can be considered a troglobiont.

Etymology.

From the Latin tactus , meaning touch, due to the fact that this species has the strongly reduced eyes and its life style as a true troglobiont relies on tactile sensations.

Figures

Figure 6. Females of Bisetifer cephalotus from the Caucasus Nature Reserve (A, B), B. gruzin from Kizil-Koba Cave (C, D), paratype of B. tactus sp. nov. from Tshernoretshenskaya Cave (E, F). A, D habitus, dorsal view B, C, E epigyne, ventral view F epigyne, lateral view. Scale bars: 0.5 mm (A, D); 0.05 mm (B, C, E, F).

Figure 7. General appearance of male holotype and female paratype of Bisetifer tactus sp. nov. from Tshernoretshenskaya Cave: A, B male and female habitus, dorsal C female prosoma, anteriorly D, E male prosoma, anteriorly in different aspects F male prosoma, dorsal. Scale bars: 0.5 mm (A, B); 0.2 mm (C – F).

Figure 8. Details of female paratype and male holotype of Bisetifer tactus sp. nov. from Tshernoretshenskaya Cave: A, B female prosoma, anterior and lateral views C, D male prosoma, lateral and anterior views E top of head part of male carapace, anterior view F male palp, retrolateral view G, H embolic division, ventro-retrolateral and ventro-apical views I fragment of male palpal tibia and paracymbium, posterior view. Abbreviations: Da – distal suprategular apophysis, Em – embolus, Pa – paracymbium, Rx – radix, Sa – setae at apex of palpal tibial apophysis. Scale bars: 0.3 mm (A – D); 0.1 mm (F); 0.05 mm (G – I).

Figure 9. Male holotype and female paratype copulatory organs of Bisetifer tactus sp. nov. from Tshernoretshenskaya Cave: A male palp, retrolateral view B male palpal tibia, dorsal view C, D bulbus, ventral and prolateral views E, F epigyne, ventral and dorsal views G spermatheca, ventral view. Abbreviations: Bs – base of spermatheca, Cd – copulatory duct, Co – copulatory opening, Da – distal suprategular apophysis, Df – fertilisation duct, Em – embolus, Fo – fertilisation opening, Hs – head of spermatheca, Me – membrane of spermatheca, Ou – outgrowths of epigyne, Pa – paracymbium, Rx – radix, Sa – setae at apex of palpal tibial apophysis. Scale bars: 0.1 mm (A – F); not scaled (G).

Figure 17. Distributions of cave-dwelling spiders in Crimea (including data from references and this work): A Tegenaria lapicidinarum (purple circle), T. parietina (blue circle), T. taurica (orange circle), Amaurobius erberi (yellow circle), Alopecosa farinosa (grey circle), Pholcus phalangioides (pink circle), Meta bourneti (red circle), Metellina segmentata (pale blue circle), M. merianae (green circle), Steatoda triangulosa (white circle) B Bisetifer gruzin (blue circle), B. tactus sp. nov. (purple circle), Caviphantes dobrogicus (green circle), Lepthyphantes leprosus (red circle), Megalepthyphantes nebulosus (pale blue circle), M. pseudocollinus (white circle), Palliduphantes khobarum (orange circle), ? Tenuiphantes zimmermanni (pink circle), Troglohyphantes exspectatus sp. nov. (yellow circle), Aituaria pontica (grey circle), A. borutzkyi (black circle). The numbering of the caves is common for both maps: 1 – in unnamed cave near the city of Bakhchisarai; 2 – Mangupskaya I (= MK- 1) Cave; 3 – abandoned aqueduct carved into an unnamed cave-spring in area of the Maksimova Datsha; 4 – Asketi I Cave; 5 – Kay-Kobasy Cave; 6 – Izumrudnaya Сave; 7 – Gekkonovaya Cave; 8 – Gnomov Cave; 9 – Tshernoretshenskaya Cave; 10 – Azis-Koba (= Kara-Koba) Cave; 11 – Mamut-Tshokrak Cave; 12 – Baidar-Tshokrak Cave; 13 – unnamed cave on northeastern slope of Mt. Kilse-Burun; 14 – Skelskaya Cave; 15 – Rodnikovskaya Cave; 16 – Koryta (= Kuznetsova) Cave; 17 – Zemlyanitshnaya Cave; 18 – Kristalnaya (= Maksimovitcha) Cave; 19 – Druzhba Cave; 20 – unnamed cave (= ? Malaya Cave) in Nizhnie Limeny (now Goluboi Zaliv); 21 – Daniltsha-Koba Cave; 22 – Ayu-Teshik Cave; 23 – Villyaburunskaya Cave; 24 – Troizkogo (= Kharkovskaya, ZUG) Сave; 25 – Avantyura Cave; 26 – Kaply-Kayanskaya (= Khaplu-Khoba) Cave; 27 – Ayu-Koba Cave; 28 – grotto in Massandra; 29 – Binbash-Koba Cave; 30 – Paskhalnaya Cave; 31 – Alushtinskaya Cave; 32 – Kizil-Koba (= Krasnaya) Cave; 33 – Sliyanie Cave; 34 – Vostotshny Potok Cave; 35 – Partizanskaya Cave; 36 – grotto on Mt. Yuznaya Demerdzhi; 37 – Tisovaya Cave; 38 – Karani-Koba Cave; 39 – Tuakskaya (= Ful-Koba) Cave; 40 – Tavrida Cave.