Nemaspela melouri, 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 : 543-548

Nemaspela melouri sp. nov.

( Figs 1–18 , Table 1 )

Type material: Holotype: ♂, 01.ii.2020, dark zone, Melouri Cave (42°23’15.1”N, 42°37’41.5”E; 415 m alt.), Ts- kaltubo Municipality , Sataplia-Tskaltubo karst massif, Imereti region, West Georgia, IZISU.

Paratypes: The same locality as holotype ; 2 ♀, 21.ii.2019, IZISU ; 2 ♀, 01.ii.2020, CJM 8705; 1 ♂, 03.iii.2020, CJM 8706; 2 ♂, 03.iii.2020, IZISU. All specimens were collected by Eter Maghradze.

Diagnosis. Generally similar in size and habitus to the other Nemaspela species from Georgian caves, but considerably smaller and with less sclerotized cuticle, and most similar in external characters to the two species from localities in the close vicinity ( N. femorecurvata and N. prometheus sp. nov.), characterized by small size (less than 2 mm, slightly smaller than N. prometheus sp. nov. including slightly shorter appendages), extremely weakly sclerotized exoskeleton, specific genital morphology (slender form of truncus and small size of basal inflated part of truncus) and armament of male chelicera (with small frontad-directed apophysis on basal article of male chelicera). No sexual dimorphism of appendages (pedipalp and legs in males and in females of the same size).

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

Description. Male (n=4). Body, dorsal side ( Figs 1–2 , 11 ): Prosoma and opisthosoma forming two independent strongly globular entities with a deep depression between them; dorsal scutum uniformly light brownish to yellowish, smooth, difficult to distinguish from neighbouring exoskeletal parts, without any darker spots or markings, no setae present on dorsal side except for a few minute ones on rear end of opisthosoma, Tu oc and eyes absent.

Body, ventral side ( Figs 2 , 11 ): Cx I–IV with a row of strong blackish setae, light brown to yellowish, similar to all parts of the ventral side, surface of Cx coarse, a few irregularly brown to black spots on Cx I–IV and on Op gen, no Tu present. Op gen and free sternites with some black setae at rear margins.

Chelicera of male ( Figs 1 , 13, 15–18 ): Rather slender; basal article slightly constricted close to its proximal end, from there slightly widened distally, scanty bristle armament, one bristle dorsally, two bristles retro-laterally, dorsally a sub-distal small and slender frontad-directed Apo slightly surpassing the front margin of proximal article; Apo ( Figs 15–18 ) smallest at basis, longer than broad, slightly widening distally, upper side smoothly rounded, less so lower side, and tapering to the rounded tip (in lateral view). Neither a pro-lateral excavation nor a pro-lateral tuft of setae present, but distinct sparse setation present consisting of three distal and one dorsal setae in lower half of Apo, the last one shortest. Second cheliceral article ( Fig. 13 ) slender, moderately inflated, with several long and strong bristles mostly on frontal surface¸ few shorter ones ventro-distally.

Pedipalp ( Figs 1–2 , 5 ): Male: Very slender and relatively long (in terms of Nemaspela morphology), all articles parallel-sided, no article except Cx noticeably inflated; all articles except Tr bearing clavate setae, these most conspicuous on Fe ventral, on Pt mostly ventral, a few dorsal, on Ti a few at distal end ventrally and on Ta on all sides. Setae on Fe but less on Pt, on ventral side longer than breadth of article at the position. No article with special armament except setation in males and females.

Legs ( Figs 1–2 ): Light brownish including Tr, extremely long and slender, thread-like, round in cross-section, armed with scattered and relatively long black setae. Many pseudo-articulations on Fe I–IV, densely packed near basis of articles, toward distal end of article distances between them increase consecutively. Number of pseudo-articulations of Fe: Fe I 7, Fe II 13, Fe III 9, Fe IV 10.

Male genital morphology ( Figs 7–10 ): Truncus penis ( Figs 7–8 ) extremely slender; basis forming a small inflat- ed part (occupying slightly less than one fifth of whole penis length) and only inconspicuously separated from the remainder of the truncus; inflated part slender and deeply split medially, completely filled by two penial muscles, their tendons spanning the whole truncus length up to the glans. Truncus parallel-sided (dorsal/ventral view, Fig. 7 ) along its length, slightly enlarged just below transition to the glans; in lateral view ( Fig. 8 ) broadest above the inflated basal part, from there slightly tapering toward central section, then slightly widening toward glans, narrowest just below glans.

Glans ( Figs 9–10 ): Only inconspicuously separated from distal part of truncus outlined, short, starting where two tendons are attached to inner truncus wall; from there slightly enlarged to proximal third in dorsal/ventral view ( Fig. 10 ) of glans, markedly broader than truncus, then continuously tapering toward stylus, stylus short, a continuation of the glans, tapering to distal rounded tip, in lateral view ( Fig. 9 ) forming a continuation of distal part of truncus, but tapering slightly to the stylus. A few short, stiff and unspecialized spicules forming the armament of glans, their arrangement symmetrical in ventral, dorsal and lateral view; even smaller spicules concentrated at the basis of stylus and more densely packed than on glans proper. Measurements are given in Table 1 .

Description. Female (n=1). In external appearance and size very similar to male ( Figs 3–4 , 12 ). Chelicera ( Fig. 14 ) similar to male, but dorso-distal Apo on basal article absent, 2 nd article more stout and bristles markedly longer. Pedipalp ( Figs 3–4 , 6 ) very similar to male including setation, size nearly identical, only palpal Fe slightly shorter than in male. Number of pseudo-articulations of Fe of legs slightly differing from male: Fe I 10, Fe II 14, Fe III 8, Fe IV 11. Measurements are given in Table 1 .

Variation. Apparently very little. Outline of the Apo of the male basal cheliceral article in the two specimens examined is nearly identical, even the setation, with two distal setae retro-laterally, one dorsally, and two (a longer one distally and a shorter one more basally) at nearly identical position ( Figs 15–18 ).

Relationships. See Discussion.

Distribution. N. melouri sp. nov. is known only from Melouri Cave in Sataplia-Tskaltubo karst massif, Imereti region, Western Georgia. The distance between the entrances of Melouri and Prometheus caves is about 2.5 km.

Figures

FIGURES 1–4. Nemaspela melouri sp. nov., Habitus of paratype specimens in lateral view. 1. Male (bar: 2 mm); 2. Male (bar: 1.5 mm); 3. Female CJM 8705 (bar: 1.5 mm); 4. Female CJM 8705 (bar: 1 mm). Arrow indicates male cheliceral apophysis. Photographs by J. Severin.

FIGURES 5–12. Nemaspela melouri sp. nov. Pedipalps in retro-lateral view. 5. Male (bar: 0.5 mm); 6. Female (bar: 0.5 mm). Penis. 7. Ventral view (bar: 0.2 mm); 8. Lateral view (bar: 0.2 mm). Glans penis. 9. Lateral view (bar: 0.05 mm); 10. Ventral view (bar: 0.05 mm). Habitus in lateral view. 11. Male (bar: 0.5 mm); 12. Female (bar: 0.5 mm).

FIGURES 13–18. Nemaspela melouri sp. nov. Chelicerae in retro-lateral view. 13. Male (bar: 0.3 mm); 14. Female (bar: 0.3 mm). Cheliceral apophyses in retro-lateral view. 15. The first male (bar: 0.05 mm); 16. The second male (bar: 0.05 mm). Cheliceral apophyses in pro-lateral view.17. The first male (bar: 0.05 mm); 18. The second male (bar: 0.05 mm).