Bioacoustics of Stygopholcus montenegrinus

Redescription Male ( type locality; ZFMK (Ar 22201)) MEASUREMENTS. Total body length 5.5, carapace width 2.15. Distance PME–PME 150 µm ; diameter PME 130 × 160 µm ; distance PME–ALE 30 µm ; diameter AME 60 µm ; distance AME-AME 20 µm . Leg 1: 50.6 (13.7 + 0.8 + 13.3 + 19.6 + 3.2), tibia 2: 9.7, tibia 3: 8.0, tibia 4: 8.5; tibia 1 L/d: 65. COLOR (in ethanol). Carapace pale whitish to ochre-yellow; ocular area, clypeus, and posteriorly between furrows slightly darker (light brown); sternum light brown, with dark brown margins and irregular dark triangular radial marks; legs ochre yellow to light brown, without dark rings, without dark lines; abdomen mostly monochromous pale gray, only above spinnerets and ventrally in gonopore area some dark marks. BODY. Habitus as in Fig. 3 . Ocular area slightly raised. Carapace with deep median pit and pair of shallow furrows diverging from pit to posterior margin of carapace ( Fig. 91 ). Clypeus unmodified. Sternum wider than long (1.40/1.05), unmodified. Abdomen oval, pointed at spinnerets. CHELICERAE. Very similar to S. skotophilus (cf. Figs 51–52 ; see also Fig. 93 ), with pair of frontal apophyses set with 3 and 4 modified hairs, respectively, with 16 and 18 modified hairs each on frontal face ( Fig. 94 ); with stridulatory ridges ( Fig. 95 ). PALPS. In general as in S. skotophilus (cf. Figs 6–8 ); coxa with retrolateral hump; trochanter barely modified; femur with distinct retrolateral process proximally, with stridulatory pick (modified hair) proximally on prolateral side ( Fig. 103 ); femur-patella joints shifted towards prolateral; tibia very large, with two trichobothria; tibia-tarsus joints shifted towards retrolateral; tarsal organ exposed ( Fig. 104 ); procursus dorsally with ~8 curved hairs (distal third curved ‘upwards’), with strong hump on prolateral side. Procursus tip ( Figs 77 , 99–102 ) with slightly projecting dorsal sclerite, strong hinged ventral sclerite (flat, wider in ventral than in lateral view), and membranous central part with brush of hair-like processes on retrolateral side, with narrow and weakly sclerotized process on prolateral side bordering ventral sclerite. Genital bulb ( Figs 79–82 ) with basal sclerite connecting to tarsus, small transparent dorsal process ( Fig. 98 ), and main sclerite consisting of retrolateral process and dorsal process; retrolateral process with bifid tip, distal part on ventral side thickened and heavily sclerotized, possibly with glandular pores distally ( Figs 105–106 ); dorsal process with two finger-shaped tips, ventral tip simple, retrolateral tip with additional strong protrusion on ventral side. LEGS. With short spines ventrally on femur 1 in two rows in distal third, prolateral row ~19 spines, retrolateral row ~24 spines; without curved hairs; few vertical hairs; retrolateral trichobothrium of tibia 1 at 4%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 with irregular platelets rather than with distinct pseudosegments. Male (variation) Some specimens with more and larger dark marks dorsally on abdomen (posterior third), few specimens without abdominal marks; dark pattern on sternum slightly variable. Tibia 1 (N = 29): 11.3–14.5 (mean 12.9); tibia 2 (N = 35): 8.1–10.8 (mean 9.6); spines on femur 1 (N = 23): 24–53 (mean 40); modified hairs on cheliceral basis (N = 70): 11–22 (mean 14.7); modified hairs on cheliceral apophysis (N = 69): 2–4 (mean 3.0); chelicerae maximum width (N = 35): 0.72–0.84 (mean 0.79); procursus length (N = 35): 1.22–1.46 (mean 1.37); bulbal measures A–E: A (N = 17): 0.34–0.43 (mean 0.37); B (N = 17): 0.10–0.15 (mean 0.13); C (N = 17): 0.24–0.27 (mean 0.25); D (N = 17): 0.25–0.29 (mean 0.27); E (N = 8): 0.82– 0.90 (mean 0.88); epiandrous spigots (N = 25): 5–9 (mean 6.2). Males from SE Montenegro (Podgorica) and NW Albania differ slightly from other specimens, most conspicuously in bulbal measure C (smaller: 0.19–0.22). Female In general similar to male ( Fig. 3 ), but femur 1 without spines, with pair of indistinct processes posteriorly on carapace ( Fig. 107 ) and pair of opposing poorly visible plates on abdomen, distance between processes/plates: 1.1. Tibia 1 (N = 28): 8.3–15.3 (mean 12.9); tibia 2 (N = 30): 6.0–10.9 (mean 9.3); epigynum width (N = 31): 0.94–1.50 (mean 1.27); epigynum length (N = 31): 0.50–0.70 (mean 0.62); epigynal measure F (N = 31): 0.22–0.40 (mean 0.30). Epigynum anterior plate semicircular, weakly protruding, with weak transversal furrows ( Figs 85–88 , 111 ), with internal structures visible in uncleared specimens: round anterior structure, short sclerites originating from posterior margin and slightly converging anteriorly; posterior plate short but wide. Internal genitalia ( Figs 83–84 , 149–150 ) with distinctive ventral arc ( Fig. 155 ; approximately as long as wide), with large pore plates ( Fig. 84 ). Females from SE Montenegro (Podgorica) and NW Albania tend to have a slightly larger epigynal measure F: 0.37–0.43 (N = 6) (cf. Figs 89–90 ).