Bioacoustics of Ciboneya

DESCRIPTION : Total length in males usually about 2–3 mm ; only C. antraia up to 4 mm . Carapace oval in dorsal view, wider than long; with distinct thoracic groove that does not reach posterior border of carapace. Eight eyes on moderately elevated ocular area; AME very small, others about equal (e.g., figs. 19, 20). Distance PME­ALE large (about 50–70% of PME diameter). Clypeus unmodified. Male chelicerae with distinctive pair of apophyses on fangs, basal segment not modified; without stridulatory ridges. Male palps long; coxa with retrolateral apophysis (figs. 24, 26, 39, 51, 63); femur long and cylindrical, without ventrodistal apophysis; bulb consisting of ovoid proximal part and mostly membranous embolar division; location of sperm duct opening not established; procursus long, relatively simple, with distinctive ventrodistal sclerotized bulge, dark distally pointed apophysis, and further elements of variable shape. Tarsal organ exposed (figs. 3, 4). Legs relatively short (leg 1 usually 3.5–5 X body length; 9 X in C. antraia ) and robust (tibia 1 l/d: 15–23; 57 in C. antraia ); leg 4 usually longest (leg formula: 4123), only in C. antraia 1423; legs without dark rings; with many vertical hairs on tibiae and metatarsi (decreasing in density from legs 1 to 4), usually without curved hairs (present only in C. antraia ), without spines; retrolateral trichobothrium of tibia 1 at about 25–30%; tarsus 1 with about 20–30 distinct pseudosegments (fig. 8). Opisthosoma about globular, either dark bluish or greenish gray with dark spots, or monochromous ochre gray ( C. antraia ); large light brown genital plate, and indistinct plate in front of spinnerets; without epiandrous spigots (figs. 10, 11); ALS with only two piriform gland spigots (one pointed, one widened; figs. 12, 13), other spinnerets typical for family. Sexual dimorphism slight. Female opisthosoma often larger and higher; legs shorter; chelicerae unmodified; tibiae and metatarsi with usual low density of vertical hairs. Epigynum large, with pair of pockets or modified areas in highly variable position. Epigynum shape highly variable even within species (it is therefore not used in the diagnoses below). MONOPHYLY : All species share the unique procursus (ventrodistal sclerotized bulge, dark distal pointed apophysis). The apophyses on the male cheliceral fangs are shared by other genera (see below) but have possibly independently evolved in Ciboneya . GENERIC RELATIONSHIPS : The presence of a retrolateral apophysis on the male palpal coxa places Ciboneya in the New World clade sensu Huber, 2000. Three South American genera ( Chibchea Huber , Galapa Huber , Blancoa Huber ) share the apophyses on the male cheliceral fangs, but otherwise these genera are extremely different in almost every aspect. The same is true of three other South American genera that share the high density of vertical hairs on the male tibiae ( Pomboa Huber , Pisaboa Huber , Waunana Huber ). Cladistic analysis did not produce a more satisfying result. Adding Ciboneya nuriae to the matrix in Huber (2001) (see codings in appendix 1) and using the same methods as previously (i.e., the same computer programs and the same criteria for tree selection as in Huber, 2001) resulted in numerous most parsimonious cladograms. All of these had Ciboneya in the New World clade, but apart from that, the position was extremely variable. Remarkably, however, in most topologies Ciboneya was very basal. In sum, even though the sister group remains obscure, the closest relatives are clearly South and Central American. NATURAL HISTORY : Three of the four species have been found in the leaf litter and under rocks in humid forests. The type species, C. nuriae , was also collected under rocks in caves, but it shows no morphological adaptations to cave life and might just enter caves occasionally (and survive there when the forests outside are destroyed). The fourth species, C. antraia , has been found only within caves, shows morphological adaptations (pale color, long legs), and is the only species where a few observations on its biology have been made (see species description below).