Bioacoustics of Chileotrecha argentinensis

Description. Male Holotype . Measurements in mm in Table 1 . Morphometric Character ♂ Holotype ♀ Paratype Total Length without chelicerae 8.03 8.04 Total Length with chelicerae 9.67 9.97 Propeltidium Width 1.78 2.40 Propeltidium Length 1.64 1.85 Propeltidium: Length/Width Ratio 0.92 0.77 Cheliceral Width 0.87 1.24 Cheliceral Length 2.34 3.58 Opisthosoma 5.06 5.18 Pedipalp Length 9.24 8.62 Leg I Length 5.93 6.82 Leg IV Length 9.92 9.96 Color in 96 % ethanol. Prosoma: Propeltidium dark brown with central portion pale brown. Lateral lobes dark brown. Ocular tubercle black. Insertion of setae yellowish. Para-, meso- and metapeltidium dark brown, insertion of setae yellowish. Chelicerae: dark brown with three longitudinal oval areas pale brown. Insertion of setae yellowish. Pedipalps: Femur and tibia brown with apical portion pale yellowish. Metatarsus dark brown. Tarsus pale yellowish. Insertion of setae pale yellowish. Legs: Legs I, II and III; coxae and trochanter pale yellowish. Femur, tibia and metatarsus brown with apical portion pale yellowish. Tarsus yellowish. Leg IV; with a similar color pattern, but the brown portion is darker. Malleoli: Brown with external margin darker. Opisthosoma: Tergites dark brown with insertion of setae yellowish. Pleurites dark grey in the dorsal half and yellowish in ventral half. Sternites yellowish. Morphology and Chaetotaxy : Prosoma: Propeltidium wider than long with some short spiniform blunt setae, separated from lateral lobes by dorsal grooves. Peltidium narrow, with a transverse row of different-sized spiniform blunt and bifurcated setae. Parapeltidium smooth. Meso and metapeltidium wider than long, with spiniform blunt and bifurcated setae. Chelicerae ( Figs. 3, 4 , 23 ): Ectal and dorsal surfaces covered by spiniform blunt and bifurcated setae. Mesal surface covered by small bristles, with two rows of plumose setae behind the teeth line and one posterior row of blunt setae. Stridulatory apparatus with eight parallel ridges ( Fig. 23 ). Movable finger with one row of plumose setae, and two rows of blunt setae. Dentition: Movable finger with one anterior (I), one intermediate (II), and one principal tooth (III) arranged in increasing size: II, I and III. Fixer finger with three anterior (I–III), one intermediate (IV), and one principal tooth (V), arranged in increasing size IV=II, I, III=V; four ectal fondal teeth arranged in increasing size II=IV, I=III, and four mesal fondal teeth arranged in increasing size II, IV, III, I with I and II separated from III and IV by a diastema (similar to mesal fondal teeth arrangement in fig. 2). Fixed finger tip slightly curved downward ( Fig. 3 ). Flagellum ( Figs. 4 , 23, 24 ): A thin translucent drop-shaped membrane, with nearly straight ventral border. The folded edge presents several rows of spicules that become more prominent in the apical area. The inner surface is covered by several spicules ( Fig. 24 ). The attachment ring of the flagellum is located at the level between principal and first ectal fondal teeth ( Fig. 4 ). Pedipalps ( Figs. 11, 12 , 28 ): All segments coated with several small truncated tip setae with pore ( Fig. 11 ), some blunt setae of different sizes, and small ventral spines. Metatarsus with a few clubbed setae ( Fig. 12 ). Tarsus short, with some clubbed setae, bifurcated setae and dorsal pores ( Fig. 28 ). The clubbed setae are twice as long as the truncate setae with pore. The blunt setae present different sizes, but are always equal or longer than clubbed setae. Tibia with five paired short spines and metatarsus with six paired short spines; the basal pair is the weakest in both segments. Legs: Leg I ( Figs. 17–20 ): Without claws and spines, covered with small blunt setae; metatarsus with some clubbed setae; tarsus with some clubbed and some bifurcated setae ( Fig. 19 ), and with an apical structure ( Fig. 20 ) that could be a vestigial remnant of the claw. Legs II, III and IV covered with some robust bifurcated setae, and some blunt setae with different sizes. The trochanters possess robust dorsal spiniform setae. Legs II and III: Tibia with two apical ventral spines; metatarsus with 1.1.1 retrolaterodorsal spines, 1.1 retrolateral spines intercalated with the retro-latero-dorsal being 1.(1).1.(1).1, and 1.1.2 ventral spines; tarsus bi-segmented with 1.2.2/2.2 ventral spines. Leg IV ( Figs. 21–22 ): Tibia with 1.1.2 ventral spines; metatarsus with 1.1.1.2 ventral spines; tarsus bisegmented with pseudo segmentation on basal segment ( Fig. 22 ), and 2.2.2-2/2.2 ventral spines. Opisthosoma: Tergites with some spiniform blunt and bifurcated setae. Sternites ( Figs. 25–27 ) with several bifurcated and a few tapered setae ( Fig. 27 ). Two pairs of microsetae ( Fig. 26 ) are placed in the posterior margin of genital plate ( Figs. 25, 26 ) and in the posterior margin of spiracular sternites I and II, whereas in postspiracular sternite I there is only one microseta on each side. Female paratypes : Measurements in mm in Table 1 . Similar to male, but more glabrous, especially on the pedipalp. Prosoma and dorsal surface of trochanters with some spiniform bifurcated setae. Propeltidium notably wider than long. The spines of pedipalps are longer than in males. Chelicerae with a dorsal hump on the fixed finger ( Fig. 5 ). Genital plate as in Figure 6 .