Nemaspela prometheus, Martens & Maghradze & Barjadze, 2021

Martens, Jochen, Maghradze, Eter & Barjadze, Shalva, 2021, Two new species of the genus Nemaspela Šilhavý from caves in Georgia (Opiliones Nemastomatidae), Zootaxa 4951 (3), pp. 541-558 : 548-549

Nemaspela prometheus sp. nov.

( Figs 19–32 , Table 2 )

Type material: Holotype: ♂, 27.xii.2019, dark zone, Prometheus Cave (42°22’37.8”N, 42°36’03.1”E; 174 m alt.), Tskaltubo Municipality , Sataplia-Tskaltubo karst massif, Imereti region, Western Georgia, IZISU.

Paratypes: The same locality as holotype . 1 ♂, 27.xii.2019, CJM 8707; 1 ♂, 02.ii.2020, ISIZU ; 1 ♀, 01.iii.2020, CJM 8708; 1 ♂, 29.vi.2020, ISIZU. All specimens were collected by Eter Maghradze.

Diagnosis. Generally similar in size and habitus to the other Nemaspela species from Georgian caves, i.e. N. femorecurvata and N. melouri sp. nov., characterized by specific genital morphology (slenderer form of truncus and smaller size of basal inflated part of truncus, glans penis in lateral view less slender than in N. melouri sp. nov.), small body size below 2 mm (species slightly larger than N. melour i sp. nov.) and appendages (longer pedipalps and legs) and armament of male chelicera (without apophysis of basal article), distinct sexual dimorphism (slightly longer pedipalps in females than in males).

Etymology. The name is given in accordance with the type locality, the single known locality of this species. Noun in apposition.

Description. Male (n=4). Body, dorsal side ( Figs 19 , 28 ): Prosoma and opisthosoma forming two independent strongly globular body parts with deep depression between them; prosoma with a small additional elevation similar to a Tu oc extending from the frontal part of opisthosoma, dorsal scutal parts of prosoma and opisthosoma uniformly light yellowish, smooth, difficult to distinguish from neighbouring exoskeletal parts, without any darker spots or markings, no setae present on dorsal side except for few minute ones on rear end of opisthosoma, Tu oc and eyes absent.

Body, ventral side ( Figs 19 , 28 ): Light yellowish to light brown. Irregular dark brown to blackish spots on the Op gen and the Cx I–IV, the upper end of Cx with a small brown margin contrasting with the whitish joint membrane and all sternites with a single row of black setae contrasting with light cuticle, Op gen with a few scattered setae.

Chelicera ( Figs 30, 32 ): Very slender and elongated; basal article slightly constricted close to its proximal end, from there slightly and continuously widened distally, distal third slightly bent downward, one bristle on dorsal side at mid-part, two long bristles dorsal sub-distally, no do Apo on basal article present; 2 nd cheliceral article remarkably slender and longish, very slightly inflated, nearly parallel-sided (in lateral view, Fig. 30, 32 ) with several scattered long and strong bristles mostly on frontal surface, some shorter ones ventro-distally.

Pedipalp ( Figs 19–20 , 22 ): Very slender and extremely long (in terms of Nemaspela morphology), all articles parallel-sided, distal end of Fe slightly swollen, Ta slightly curved downward, no article except Cx noticeably inflated; all articles except Tr bearing scattered clavate setae, these most conspicuous on Fe ventrally, on Pt mostly ventrally on distal half, on Ti a few at basal end ventrally and on Ta on all sides but scattered as well. Setae on Fe and on Pt on ventral side longer than breadth of article at the position. No article with special armament in males and females.

Legs ( Figs 19–20 ): Light brownish tending to yellowish brownish and yellowish toward distal end, Tr mottled dark brownish, articles extremely long and slender, thread-like, round in cross-section, armed with some scattered and short black setae. Many pseudo-articulations on Fe I-IV ( Fig. 19 ), densely packed near basis of articles, towards distal end of article distances between them consecutively more extended; no pseudo-articulations near distal end. Number of pseudo-articulations of Fe of legs: Fe I 15, Fe II 19, Fe III 13, Fe IV 18.

Male genital morphology ( Figs 24–27 ): Truncus penis ( Figs 24–25 ) extremely slender; basis forming a small inflated part (occupying about one sixth of whole penis length) and only slightly separated from the rest of the truncus; inflated part slender, broadest at proximal end and deeply split medially, completely filled by two penial muscles, their tendons spanning the hole truncus length up to the basis of the glans. Truncus nearly parallel-sided in dorsal/ventral view all over its length (dorsal/ventral view, Fig. 24 ), but slightly and continuously tapering to just below transition to the glans; in lateral view ( Fig. 25 ) truncus slightly narrower, strictly parallel-sided and hardly tapering toward glans. Glans ( Figs 26–27 ) only inconspicuously separated from distal part of truncus as outlined, though distinctly widened at basis, but only very slightly broader than truncus ( Fig. 26 ), short, starting where two tendons are attached to inner truncus wall, lateral outline only slightly rounded, then continuously tapering toward stylus, stylus short, a continuation of the glans, tapering to a distinctly pointed distal tip. Glans in lateral view ( Fig. 27 ) a continuation of the distal part of truncus, but slightly enlarged dorsally for most of dorsal length, stylus distinctly bent to dorsal side. A few rather long, stiff and unspecialized spicules forming the armament of glans, their arrangement symmetrical in ventral, dorsal and lateral view; one double row each on lateral, ventral and lateral sides, spicules of the same size at the basis of stylus, slightly more densely packed than on glans proper. Measurements are given in Table 2 .

Description. Female (n=1). External morphology of body generally similar to male ( Figs 21 , 23 ). Chelicera ( Fig. 31 ) similar to male, but 1 st and 2 nd articles even longer and thus more slender, setation of both articles similar to male, but front setae of 2 nd article much longer than in male, the length about the diameter (in lateral view, Fig. 31 ) of 2 nd article. Pedipalp ( Fig. 23 ) very similar to male including setation, but all articles markedly longer (see Measurements). Number of pseudo-articulations of Fe of legs: Fe I 17, Fe II 21, Fe III 18, Fe IV 21. Measurements are given in Table 2 .

Variation. The available specimens are rather homogeneous in size, coloration and appendages. For differences between sexes see above.

Relationships. See Discussion.

Distribution. Known only from Prometheus Cave in Tskaltubo Municipality, Sataplia-Tskaltubo karst massif, Imereti region, Western Georgia.

Figures

FIGURES 19–21. Nemaspela prometheus sp. nov. Habitus in lateral view. 19. Female (bar: 1 mm); 20. Female (bar: 2 mm); 21. Male (bar: 2 mm). Photographs by J. Severin.

FIGURES 22–29. Nemaspela prometheus sp. nov. Pedipalps in retro-lateral view. 22. Male (bar: 0.8 mm); 23. Female (bar: 0.8 mm). Penis. 24. Ventral view (bar: 0.2 mm); 25. Lateral view (bar: 0.2 mm). Glans penis. 26. Ventral view (bar: 0.05 mm); 27. Lateral view (bar: 0.05 mm). Habitus in lateral view. 28. Female (bar: 0.5 mm); 29. Male (bar: 0.5 mm).

FIGURES 30–32. Nemaspela prometheus sp. nov. Chelicerae in retro-lateral view. 30. Male (bar: 0.8 mm); 31. Female (bar: 0.8 mm). Chelicera in pro-lateral view. 32. Male (bar: 0.8 mm).