Bioacoustics of Nerudia centaura

Description Male ( holotype ). Measurements: Total body length 1.9, carapace width 0.77. Distance PME–PME 90 µm; diameter PME 55 µm; distance PME–ALE 30 µm; distance AME–AME 20 µm; diameter AME 40 µm. Leg 1: 4.55 (1.25 + 0.25 + 1.30 + 1.30 + 0.45), tibia 2: 1.10, tibia 3: 1.00, tibia 4: 1.38; tibia 1 L/d: 14. Colour (in ethanol): Prosoma and legs ochre to light brown; legs without dark rings; abdomen monochromous pale grey. Body: Habitus as in Figure 1C . Ocular area barely raised. Carapace without thoracic groove. Clypeus unmodified. Sternum wider than long (0.56/0.48), without anterior processes. Abdomen globular. Chelicerae: As in Figure 16G, H ; pair of frontal apophyses directed downwards, with obtuse tip slightly flattened; stridulatory files on pair of distinct lateral protrusions. Palps: As in Figure 15 ; coxa unmodified; trochanter with indistinct ventral projection; femur cylindrical, only slightly widened distally, proximally with indistinct retrolateral hump and prolateral stridulatory pick (modified hair); patella short; tibia globular; procursus ( Fig. 16A–C ) simple, in lateral view bent towards dorsal, in dorsal view bent towards prolateral, with pointed tip; genital bulb ( Fig. 16D–F ) large, with strong pointed ventral apophysis, embolus partly membranous, dorsally with distinct sclerite. Legs: Without spines and curved hairs; vertical hairs in high densities on tibiae 1–2; retrolateral t r i c h o b o t h r i u m o f t i b i a 1 a t 6 8%; p r o l a t e r a l trichobothrium absent on tibia 1; tarsus 1 with six to seven pseudosegments, distally distinct. Variation (male): Tibia 1 in 12 males (including holotype ): 1.15–1.33 (mean 1.26). Female: In general, similar to male ( Fig. 1D ) but with usual low density of vertical hairs on tibiae. Tibia 1 in 22 females : 1.07–1.48 (mean 1.28). Epigynum ( Fig. 17A ) anterior plate weakly protruding, with large, whitish posterior indentation; posterior plate large, simple. Internal genitalia ( Figs 16I , 17B–E ) with simple ‘receptacle’ ( Fig. 17C ) and unique tubular membranous structure in anterior position (possibly opening towards the outside, not towards the uterus externus).

Diagnosis: Easily distinguished from known congeners by dark coloration of prosoma ( Fig. 1C, D ), by shape of procursus ( Fig. 16A–C ; dorsal hump at basis, strongly bent towards dorsal, pointed tip), by bulbal processes ( Fig. 16D–F ; strong pointed ventral apophysis; embolus slightly shorter, with strong dorsal sclerite), by male chelicerae ( Fig. 16G, H ; strong frontal apophyses with flattened tips; stridulatory files on strong lateral protrusion), and by epigynum and female internal genitalia ( Figs 16I , 17 ; epigynal plate with large, whitish posterior indentation angular anteriorly; internal genitalia with indistinct posterior ‘receptacle’ and unique anterior tubular membranous structure).