Bioacoustics of Artema martensi

Description. Male ( holotype ): Measurements . Total length 9.3, carapace width 4.5. Distance PME-PME 220 µm ; diameter PME 210x 230 µm ; distance PME-ALE 100 µm ; diameter AME 230 µm ; distance AME-AME 60 µm . Leg 1: 68.0 (17.1 + 2.1 + 19.2 + 24.9 + 4.7), tibia 2: 14.9, tibia 3: 11.2, tibia 4: 14.3; tibia 1 L/d: 42; femora 1–4 diameters (at half length): 0.70, 0.72, 0.72, 0.76. Color (in ethanol). Carapace pale ochre-yellow, with brown median mark and three pairs of lateral marks (anterior pair very small); ocular area laterally light brown; clypeus with brown median band; sternum ochre-yellow, with dark brown margins and dark ochre median mark; legs ochre-yellow, metatarsi and tarsi light brown; femur 1 proximally red-brown; femora and tibiae with light tips and dark subdistal rings, additional dark ring on patellae + tibiae proximally; abdomen pale grey, dorsally and laterally with distinct pattern of large dark marks; ventrally monochromous. Body . Habitus as in Figs 1–2 . Ocular area slightly elevated. Deep thoracic pit transforming posteriorly into shallow median furrow. Clypeus unmodified but rim more sclerotized than in female. Sternum wider than long (2.6/2.1), unmodified. Abdomen globular, slightly higher than long and laterally slightly compressed; gonopore with four epiandrous spigots. Chelicerae . As in Figs 8–9 , distally with pair of strongly protruding frontal processes set with large modified (cone-shaped) hairs (25 and 27, respectively); with additional pair of rounded processes more proximally (arrows in Figs 8 and 9 ); lateral stridulatory ridges very indistinct, barely visible in dissecting microscope. Palps . As is Figs 5–7 ; coxa unmodified; trochanter ventrally slightly protruding; femur very large, distally strongly widened, proximally with retrolateral ventral process, whitish ventral area, and very small prolateral stridulatory pick (modified hair); patella very short but ventrally closed; femur-patella joints in dorsal position (i.e., not shifted to one side), very close together; tibia-tarsus joints shifted toward retrolateral side; tarsus without macrotrichia; procursus ( Figs 10–13 ) short, with distinct dorsal process and indistinct ventral pocket, distally strongly widened (in dorsal view), without notch, with whitish distal cushion-like structure; distally on ventral side with distinctive apophysis (arrows in Figs 10 and 13 ); genital bulb ( Figs 14–17 ) with spiraling proximal sclerite and several distal processes: processes a and b large, with whitish embolus in-between; process c distinct and sclerotized, with very small and indistinct scales; process d small and light. Legs . Without spines; with weakly curved hairs on all tibiae; few vertical hairs; with three types of ‘regular’ mechanoreceptors (i.e., except trichobothria and short vertical hairs): very long and strong hairs (up to 2.4 mm long, ~ 30 µm thick at basis), much shorter strong hairs (~ 0.1–0.3 mm long, 10–20 µm thick), and very small and thin hairs, in high density (~ 0.1 mm long, ~ 5 µm thick); retrolateral trichobothrium of tibia 1 at 8%; prolateral trichobothrium present on all tibiae; tarsal pseudosegmentation not visible. Female: In general similar to male ( Figs 3–4 ) but chelicerae with very distinct stridulatory files and leg tibiae with additional (less distinct) dark ring at ~1/3 of length. Tibia 1 in 2 females : 14.0, 18.3 (missing in third female). Epigynum as in Figs 19–21 , main epigynal plate semi-circular to bean-shaped, weakly protruding, with pair of dark areas laterally; posterior plate large, with distinctive pair of lateral processes (arrows in Figs 20 and 21 ) (slightly smaller in female from SW Ida Ougnidif); with pair of distinct elevations (“anterior epigynal processes”) in front of epigynum. Internal genitalia ( Figs 22–24 ) with pair of elongated brown pore plates, mostly membranous dorsal arc with cushion-like median structure (arrow in Fig. 23 ), ventral arc partly sclerotized, with pair of ventral processes (directed towards epigynal plate). Natural history. This species does not show any troglomorphism and can be classified as troglophilic. At the type locality, the surrounding area is flat and does not seem to provide suitable habitats ( Figs 25–28 ). No webs were seen among larger rocks outside of two neighboring caves (or cave entrances). Within the caves, the spiders were found in the entrance area and slightly beyond (in the twilight area), with indistinct webs but sitting on the rock surface. They shared the caves with a much more abundant pholcid species, closely related to Holocnemus aurouxi Barrientos, 2019 . The second locality near Ida Ougnidif is a cave with a large opening, i.e. a shelter rather than a cave ( Fig. 29 ) but with crevices possibly leading into inaccessible deeper sections.