Bioacoustics of Caipira mineira

Description. MALE ( holotype ). Measurements : Total length 1.20, carapace width 0.50. Distance PME – PME 30 µm; diameter PME 45 µm; distance PME – ALE 10 µm; diameter AME 20 µm; distance AME – AME 10 µm. Leg 1: 3.23 (0.93 + 0.17 + 0.90 + 0.83 + 0.40), tibia 2: 0.80, tibia 3: 0.70, tibia 4: 0.98; tibia 1 L / d : 15. — Color (in ethanol): Carapace whitish with pair of lateral submarginal ochre bands, clypeus ochre; sternum white; legs pale ochre-yellow, without dark rings; abdomen monochromous ochre gray. — Body : Habitus as in Fig. 3 a. Ocular area barely raised. Thoracic groove shallow (Fig. 9 a). Clypeus unmodified. Sternum wider than long (0.40 / 0.30), unmodified. Abdomen globular. ALS with one strongly widened spigot, one long pointed spigot, and apparently six cylindrical spigots (Fig. 10 b). PMS with two slender spigots (cf. Fig. 10 f). Gonopore with four epiandrous spigots arranged in two pairs (Fig. 9 f). — Chelicerae : As in Fig. 7 a, b, with pair of frontal pointed apophyses directed towards median, without modified hairs (Fig. 9 c, d), and pair of lateral sclerotized humps with series of frontal ridges (Fig. 9 d), without lateral stridulatory ridges. — Palps : As in Figs 5 and 11; coxa unmodified; trochanter with short ventral apophysis (~ 25 µm long); femur large and strongly widened, dorsally bulging, without stridulatory pick; femur-patella condyles shifted toward prolateral side; tibia with two trichobothria in very proximal position; tibia-tarsus condyles slightly shifted toward prolateral side; tarsus with strong prolateral-ventral process and deep notch ventrally at basis of procursus (Fig. 6 b); tarsal organ exposed (Fig. 14 a), diameter ~ 10 µm; procursus (Fig. 6 a – c) slender, proximally with ventral process, distally with dorsal rounded sclerite and ventral membranous hooked element (Fig. 11 f); genital bulb (Fig. 6 d – f) slightly elongated, with distinctive dorsal protruding flap and distal pointed sclerite, sperm duct opening distally on bulb (arrows in Fig. 11 a, c). — Legs : Without spines, without curved hairs. Tibiae, metatarsi, and tarsi with round cuticular ‘ plates’ (Figs 12 a, 13 c) at regular intervals, diameter ~ 4–5 µm. Without rimmed pores. With sexually dimorphic short ‘ vertical’ hairs (Fig. 13 a) on tibia 1 only, diameter proximally 1.4 µm, length ~ 15–20 µm; putative chemoreceptors on all legs, especially distally, i. e. on metatarsi and tarsi, similar to sexually dimorphic short ‘ vertical’ hairs but with several side branches (Fig. 13 b) and slightly thicker (diameter proximally 1.6 µm). Ventrally on metatarsi 3 and 4 with slender hairs (Fig. 12 a – d); diameters proximally 1.6 µm, versus 2.8 µm in neighboring mechanoreceptors; shape of hair basis similar to neighboring mechanoreceptors (Fig. 12 c), but shaft similar to trichobothria (cf. Fig. 12 e – f); metatarsus 3 with only three such hairs, metatarsus 4 with ~ 14; distally very thin and long, with distinctively widened tips (Fig. 12 d; ~ 1.4 µm diameter, versus 0.6 µm subdistally). Bases of trichobothria capsulate, unmodified (Fig. 12 e, f); trichobothria feathered (Fig. 12 e, f); retrolateral trichobothrium of tibia 1 at 48 %; prolateral trichobothrium absent on tibia 1. No tarsal pseudosegmentation visible in SEM (Fig. 13 e) and in compound microscope. Leg tarsal organs exposed (Fig. 14 f), diameters ~ 3–6 µm. Main and median tarsal claws as typical for family; main claws with 9–10 tines (Fig. 13 d – f). Tarsus 4 distally with two comb-hairs on prolateral side (Fig. 13 f).

Description. FEMALE . In general very similar to male, including size and carapace pattern (Fig. 3 b). Chelicerae also without stridulatory ridges (Fig. 9 e). Tibia 1 in 14 females : 0.83–0.93 (mean 0.89). With short chemoreceptive hairs like in male but without sexually dimorphic short ‘ vertical’ hairs. Spinnerets as in male (Fig. 10 c – f). Palpal tibia with only one trichobothrium (Fig. 12 e). Epigynum (Fig. 8 a, b) anterior plate light brown, strongly indented posteriorly, with pair of pockets close together near posterior margin (Fig. 7 c); posterior epigynal plate large but simple, with pair of darker marks anteriorly (muscle attachment sites?). Internal genitalia partly visible in uncleared specimens; with sclerotized roundish median structure from which pair of lateral sclerites originate; pore plates poorly visible, apparently at median origin of lateral sclerites (Fig. 7 d); with large anterior membranous arc.