Filistata albens Zonstein & Marusik, 2019

Filistata albens Zonstein & Marusik, 2019 View in CoL

( Figs 1–3)

Filistata albens Zonstein & Marusik, 2019: 62 View in CoL , figs 7A–G, 27D (♂); Magalhaes et al. 2022: 168, fig. 100 (♂).

Emended diagnosis: Males of F. albens resemble those of F. maguirei in possessing a very long palp, but differ in a considerably longer and dissimilarly arranged embolus ( Figs 1D, 2, cf. Zonstein & Marusik 2019, figs 7E, F, 21A–C). In F. albens the embolus bears a longitudinal keel, which is less elevated than in F. betarif , but is higher than the embolic keel in males of F. insidiatrix ( Fig. 2, cf. Magalhaes et al. 2022, figs 5, 6, 8). In F. albens , moreover, this keel is clearly S-shaped (when viewed ventrally) and more curved than the embolic keel in the other two species ( Fig. 2C). The structure of the spermathecae in F. albens does not differ significantly from that in F. insidiatrix and F. betarif ( Figs 3G, H, cf. Zonstein & Marusik 2019, figs 7E, F, 21A–C; Magalhaes et al. 2022, figs 3C–F, 9), and females can be clearly distinguished from the related species ( F. betarif and F. insidiatrix ) due to their noticeably (ca. 1.5–2 times) smaller size and almost uniformly pale colouration characteristic for all specimens.

Redescription: Male (from Mt Ramon). Habitus as in Fig. 1A. Total length 4.16.

Colour in alcohol: Carapace very pale brownish white, with light brownish short and narrow medial stripe and anterior margins; two short marks located symmetrically in postocular area and lateral margins of clypeus also gently light brown; eye tubercle blackish brown, chelicerae, labium, sternum, entire legs and palps, and spinnerets milky white, with weak yellowish brown tint; abdomen dorsally uniformly light greyish brown, ventrally pale yellowish grey.

Cephalothorax: Carapace ( Fig. 1B) 1.79 long, 1.34 wide. Clypeus 0.21 long. Eye diameters and interdistances: AME 0.09, ALE 0.14, PLE 0.13, PME 0.11; AME–AME 0.08, PME–PME 0.13. Fovea narrow slit-like. Sternum, labium and maxillae as in Fig. 1C.

Legs and palp lengths as following:

Palp

I II III IV

Femur 2.31 3.28 2.67 2.40 3.36 Patella 0.36 0.72 0.56 0.47 0.61 Tibia 1.97 3.60 2.43 1.81 3.25 Metatarsus – 3.64 2.77 2.68 3.55 Tarsus 0.36 1.77 1.26 1.08 1.44

Bulb 0.29 – – – –

Total 5.29 13.01 9.69 8.44 12.21

Copulatory organs ( Figs 1D, 1E, 2B–D): Palp: femur 11×, patella 1.8×, tibia ca. 9.3×, cymbium 2× as long as wide; tibia 1.1× as long as carapace. Cymbium with one pair of long prolateral setae. Entire copulatory bulb slightly shorter than cymbium. Embolus as long as cymbium and twice longer than wide, tapering, hooked and flattened subapically, with moderately elevated S-shaped keel stretching along its ventral and then (apically) retrolateral side.