Bioacoustics of Nerudia

Description Male. Measurements: Total body length 1.4–1.9, carapace width 0.6–0.8. Legs relatively long (compared to other Ninetinae ), tibia 1 usually ~1.1–2.0 (longer in the new species N. rocio , single male: 2.5); tibia 1 L/d 14–31; metatarsus 1 length ~1.0–1.2 × tibia 1 length; tibia 2 always shorter than tibia 4 (tibia 2/tibia 4: 0.8–0.9). Colour: Live specimens pale ochre-grey to light brown ( Fig. 1 ); carapace often with darker median mark; abdomen colour variable, often darker than prosoma, only in N. centaura distinctively lighter than prosoma ( Fig. 1C ), without or with indistinct marks; legs without dark or light bands. Colour in ethanol similar but paler. Body: Ocular area barely raised, eight eyes, AME relatively large (diameter: 35–50 µm, i.e. 60–85% of PME diameter). Carapace without or with indistinct thoracic groove (cf. Figs 7B , 11A , 29A ). Clypeus usually barely modified, rim slightly more sclerotized than in female, in N. nono also more bulging than in female, in some species with pair of shallow indentations for genital bulbs at rest ( Figs 7A , 11B ). Sternum wider than long, usually with pair of variably distinct anterior processes near leg coxae 1, processes apparently without pores ( Fig. 29G ); sternum processes absent in N. centaura . Abdomen globular; four epiandrous spigots arranged in two pairs ( Figs 11F , 29H ); ALS with seven spigots each ( Fig. 30G ): one strongly widened spigot, one long pointed spigot and five cylindrical spigots (one of which is unusually large); PMS with two short, pointed spigots ( Fig. 30G ); PLS without spigots (cf. Fig. 12D ). Chelicerae: Usually with pair of simple frontal apophyses (e.g. Fig. 5G, H ; absent in N. trigo ), tip often flat, i.e. wide in frontal view, pointed in lateral view ( Fig. 11C, D ); often with patches or brushes of stronger hairs; with stridulatory files on variably distinct lateral protrusions ( Figs 11B, C , 29C ). Palps: Coxa unmodified; trochanter with indistinct ventral projection; femur cylindrical, slightly widened distally, proximally without or with low retrolateral hump, with prolateral stridulatory pick (modified hair; Fig. 29E ); patella short; tibia globular, with two trichobothria; palpal tarsal organ raised, capsulate ( Figs 7E , 11E , 30C ), with small opening (diameter of opening ~1.6–1.9 µm); procursus simple, without dorsal flap, not strongly elongated, straight or bent towards dorsal, tip with complex cuticular microstructure ( Fig. 29B ); genital bulb with simple ventral apophysis and dorsal embolus (e.g. Fig. 5F ). Legs: Without spines and curved hairs; usually with short vertical hairs in higher density on tibia 1 or tibiae 1 and 2 ( Figs 8A, B , 30A ; length of hairs ~20 µm). Trichobothria in usual arrangement: three on each tibia (except tibia 1: prolateral trichobothrium absent), one on each metatarsus, slightly feathered ( Fig. 30B ); length of dorsal trichobothrium on tibia 1: ~80 µm; retrolateral trichobothrium of tibia 1 in distal position (at 58–70% of tibia length). Metatarsi and tarsi with dorsal rows of tiny pores with cuticular rim (diameter of opening ~0.6 µm; cf. Fig. 18C, D ). Tarsus 1 with six to eight pseudosegments, distally distinct, proximally usually indistinct; tarsus 4 distally with one comb-hair on prolateral side ( Fig. 12F ); leg tarsal organs small, capsulate ( Fig. 30E ), with small opening (diameter of opening ~ 1.2–1.6 µm); three claws ( Figs 12E , 18G ). Female: In general (size, colour, body shape), similar to male but chelicerae without stridulatory files ( Figs 7D , 24F , 29D ), sternum without pair of anterior humps, palpal tarsal organ only weakly raised ( Figs 12A, B , 24B ), and leg tibiae with usual low number of short vertical hairs; legs either slightly shorter than in males or of same length (only in the new species N. ola with reasonable sample size: male/female tibia 1 length: 1.08). Spinnerets, leg pores, leg tarsal organs and comb-hairs as in male ( Figs 7F , 8D–F , 18B, H , 24H , 30E, H ). Main (anterior) epigynal plate rectangular to trapezoidal or semi-circular, weakly protruding, posteriorly straight or with variably distinct median indentation (e.g. Figs 17A , 32A ); posterior plate simple, short but wide, usually wider than anterior plate. Internal genitalia simple, sometimes with distinct median receptacle-like structure (e.g. Figs 6B , 10B ), apparently without or with indistinct pair of pore plates (arrows in Figs 10B , 14B , 23B ).