Bioacoustics of Cybaeolus pusillus

Diagnosis Males and females differ from those of other Cybaeolus species by lacking a rastellum of thick setae on the cheliceral promargin ( Fig. 17B ). In addition, males are similar to those of C . rastellus by having a dorsally curved retrolateral patellar process with three to five acute tips ( Fig. 19A–C ), but differ by the lack a median apophysis in the tegulum ( Fig. 19A, B ), which is found in males of C . rastellus ( Fig. 19D, E ) and C. delfini ( Fig. 19G, H ). Females are similar to those of C. rastellus by having the copulatory openings anteriorly in the epigyne but can be distinguished by the copulatory ducts describing complete loops around the spermathecae, visible in ventral view ( Figs 20A , 21B, D ). In comparison, in C. rastellus the loops are restricted to the mesal margins of the spermathecae ( Figs 20C, D , 23B–D ). The copulatory openings are usually closer to each other than in C. rastellus , but this is variable across specimens ( Fig. 21D–F ). Description Male (from Región del Maule , Talca Prov. , Alto Vilches , 14–15 Nov. 1993 , elev. 1180 m , 35° 36 ʹ S , 71° 04 ʹ W , N.I. Platnick , K.M. Catley , M.J. Ramírez , and R . T . Allen , AMNH ; complemented with SEM images from other specimens). Total length 2.36. Carapace 1.00 long, 0.85 wide. Abdomen 1.46 long, 0.86 wide. Eye diameters and interdistances AME 0.05, ALE 0.08, PME 0.07, PLE 0.07, PLE 0.08; AME – AME 0.04, AME –ALE 0.03, PME–PME 0.07, PME–PLE 0.06, ALE–PLE contiguous; MOQ length 0.18, anterior width 0.14, posterior width 0.21. Clypeus height 0.14 (2.8× diameter of AME ), orange-brown without marks. Carapace bright orange-brown, thoracic marks extremely faint. Chelicerae length 0.39, ratio 0.45, orange brown, external-posterior side with subtle stridulatory file. Endites orange-brown, not projecting posteriorly. Labium yellow-brown. Sternum slightly wider than long, length 0.57, width 0.64, orange-brown, darker towards edges. Abdomen dorsum mottled white with brick-red stripe over cardiac region extending posteriorly to four indistinct chevrons, laterally dark grey; venter silvery white with dusky median area, broad brick-red band around spinnerets. Pedipalp femur, patella and tibia light-yellow, cymbium dark brown. Pedipalp cymbium distinctly rounded, median apophysis absent, only a pale unsclerotized patch in its place ( Fig. 19B ); tibial apophysis long and procurved, patellar apophysis recumbent on retrolateral surface armed with three or four teeth ( Fig. 19B, C ). Spinnerets in relatively compact group ( Fig. 4A ), pigmented, dusky-yellow with distal segments darker. Proximal segment of ALS 3.8 × length of distal segment; distal segment of PLS 0.26× length of proximal segment, PLS length equal to ALS . ALS total length 0.19; basal width 0.09, distal segment length 0.05, proximal segment length 0.14. PMS length 0.12, PLS total length 0.19; distal segment length 0.04, proximal segment 0.15. Spigot morphology: ALS with one major ampullate gland spigot flanked by nubbin, and 12 piriform gland spigots ( Fig. 4C ). PMS with one minor ampullate gland spigot and three aciniform gland spigots, one slightly larger ( Fig. 4B ). PLS with four aciniform gland spigots ( Fig. 4D ). Epiandrous spigots absent ( Fig. 4E ). Legs all light yellow-brown, femora with black annulations distally, tibiae and metatarsi with faint markings. Leg measurements (formula 1243): leg I (total 3.62) femur 0.89, patella 0.31, tibia 0.89, metatarsus 0.90, tarsus 0.54; leg II (3.55) 0.99, 0.28, 0.86, 0.85, 0.57; leg III (2.91) 0.85, 0.28, 0.67, 0.66, 0.45; leg IV (3.29) 0.97, 0.27, 0.73, 0.81, 0.51; palp (1.02) 0.34, 0.21, 0.14, -, 0.33. Female ( holotype , Fig. 21G–J , complemented with SEM data from other specimens ). Total length 2.38. Carapace 1.00 long, 0.80 wide. Abdomen 1.46 long, 0.99 wide. Eye diameters and spacing: AME 0.05, ALE 0.07, PME 0.07, PLE 0.07; AME – AME 0.04, AME –ALE 0.06, PME–PME 0.07, PME–PLE 0.09, ALE–PLE virtually contiguous; MOQ length 0.19, anterior width 0.14, posterior width 0.21. Anterior eye row slightly procurved in anterior view, posterior row slightly procurved in dorsal view. Clypeus height 0.11 (2.2× diameter of AME ). Carapace pale-yellow, with no thoracic markings, with only a trace of black border to Carapace. Chelicerae without rastellum ( Fig. 17B ). Endites yellow-brown, as long as wide, posterior lateral edge rounded. Sternum yellow-brown with no markings, slightly wider than long. Abdomen dorsum mottled white over entire surface, anterior mid-dorsal aspect with darker line; venter white mottled blotches. Epigyne flat, centrally rugous, copulatory ducts open medially and anteriorly ( Figs 17H, I , 20A, B , 21B, D, G, H ), beginning with a lateral loop that passes dorsally to the spermatheca and continues in a second ventral loop that surrounds it; spermathecae large, spherical. Spinnerets in relatively compact group ( Fig. 3A ), yellow-brown. ALS conical with wide base, PLS and PMS cylindrical, proximal segment of ALS 8 × length of distal segment; distal segment of PLS 0.25× length of proximal segment, PLS smaller than ALS . ALS total length 0.18; basal width 0.13, distal segment length 0.2, proximal segment length 0.16. PMS length (not accessible); PLS total length 0.15; distal segment length 0.03, proximal segment length 0.12. Spigot morphology ( Fig. 3 ): ALS with major ampullate gland spigot flanked by nubbin, and 12 piriform gland spigots ( Fig. 3B ). PMS with one minor ampullate gland spigot, one cylindrical gland spigot, and five to six aciniform gland spigots, one slightly larger ( Fig. 3C ). PLS with one cylindrical gland spigot, six aciniform gland spigots ( Fig. 3D ). Legs all pale straw-colour with no markings. Leg measurements (formula 2143): leg I (total 2.96) femur 0.83, patella 0.29, tibia 0.67, metatarsus 0.73, tarsus 0.46; leg II (3.07) 0.82, 0.28, 0.71, 0.78 0.48; leg III (2.55) 0.76, 0.28, 0.51, 0.61, 0.39; leg IV (2.89) 0.76, 0.27, 0.72, 0.74, 0.40; palp (1.06) 0.34, 0.18, 0.21, -, 0.33. Pattern of spines: (most spines missing) pedipalp tarsi p1-1-1, r1-1-1. Femora: I p0-0-1 0-1. Tibiae: I d1-0-1; IV d1-0-1, v0-1-0. Metatarsi: III p0-1-1, v0-1-2, r0-0-1; IV p0-1-1, v0-1-2, r0-0-1.