Bioacoustics of Galapa

Description (amendments; see Huber 2000 ). Male MEASUREMENTS.Total body length~1.0–1.5.Male carapace width0.38–0.60.Distance PME-PME35–45µm; diameter PME30–45 µm;distance PME-ALE 15µm;distanceAME-AME 10–15 µm;diameterAME 15–30µm.Tibia 1 length 0.41–0.74.Tibia 1 L/d:9–10.Leg formula 4123. Diameters of leg femora 0.075–0.10, of leg tibiae:0.05–0.06. COLOUR (in ethanol). Prosoma and legs pale ochre-yellow, carapace without pattern, legs without darker rings; abdomen ochre-grey, monochromous or with indistinct internal marks. BODY. Ocular area not raised. Carapace without thoracic groove ( Figs 6A , 20A , 27A ). Clypeus either not more protruding than in females ( Galapagos species) or slightly more protruding than in females and with sclerotized rim (mainland species), in G. murphyi also with cluster of sexually dimorphic hairs ( Fig. 27C ). Sternum slightly wider than long, with pair of indistinct anterior humps near coxae 1 ( Fig. 13D ; ~5–20 µm high, 20 µm diameter at basis). Abdomen globular. Gonopore either with four epiandrous spigots arranged in two pairs ( G. baerti , G. bella , G. gabito ; Figs 6F , 13E ; see also Huber 2000 : fig. 127) or without epiandrous spigots ( G. spiniphila , G. murphyi ; Figs 20E , 28E, F ). ALS with one strongly widened spigot, one long pointed spigot, and five cylindrical spigots, of which one is much wider than the others ( Figs 6C , 22A, B , 28A ); PMS with two conical spigots ( Figs 6C , 22A , 28A ); PLS without spigots. CHELICERAE. Chelicerae main segment unmodified ( Fig. 3 ); with stridulatory files consisting of ~30–50 ridges, distances between ridges either constant throughout (1.5–1.6 µm) or wider proximally (2.0 µm) than distally (1.1 µm), either with or without further fine subdivision ( Figs 8B , 13A , 20C , 27F ). Fang with curved proximal process ( Figs 8A , 13C , 27E ). PALPS. Palpal coxa unmodified. Trochanter without process or with very short ventral protrusion. Femur proximally with prolateral stridulatory pick (modified hair; Figs 8C , 20D ), distally slightly widened but without modification. Femur-patella joints variably shifted towards prolateral side. Tibia oval, with two trichobothria. Tibia-tarsus joints slightly shifted towards retrolateral side. Palpal tarsal organ weakly to strongly raised ( Figs 9A–C , 14E , 23D , 29E ; see also Huber 2000 : fig. 77), diameter 4.1–6.7 µm, diameter of opening 1.0–1.7 µm. Procursus retrolateral distal process simple ( Figs 7B , 14B , 21B ) or bifid ( Fig. 25B , 29C ); dorsal process curved towards prolateral; tip of dorsal process covered by large flap of genital bulb or lodged in pocket of genital bulb ( Figs 7B , 14B , 21B ). Genital bulb with distal apophysis ( Figs 7B , 17B, C , 25B, C ), in G. spiniphila also with retrolateral-dorsal process and pair of ventral processes ( Figs 17 , 21C, D ); in G. gabito and G. murphyi with small prolateral distal apophysis (arrows in Figs 12B , 25A ; 29D ); sperm duct opening on prolateral-ventral side directly on bulb ( Figs 7H , 21D , 29D ). LEGS. Without spines and curved hairs. Without slender metatarsal hairs (as described in Huber et al. 2023c ). Sexually dimorphic short vertical hairs present on tibiae 1 and 2 ( Figs 8E–H , 15A, B , 23A, B , 30A ), barely visible in dissecting microscope, length ~15–17 µm, diameter at basis 1.0–1.2 µm. Chemoreceptive hairs similar in size (length ~10–14 µm, diameter at basis 1.3–1.7 µm) but with side branch ( Fig. 30B, C ) and mostly near leg tips. Retrolateral trichobothrium of tibia 1 at 52–66%. Prolateral trichobothrium absent on tibia 1. Base of trichobothria either evenly rounded ( Fig. 10D ) or with proximal ridge ( Figs 15C , 30D, E ). Legs with round cuticular plates ( Figs 10A, B , 15D , 23F , 30E , 31F ; diameter 4–7 µm) and rimmed pores ( Figs 10A–C , 15E , 23G , 31F ; outer diameter 3.0–3.7 µm, diameter of opening 0.2–0.4 µm) apparently on all leg segments. Tarsus 1 with five pseudosegments, fairly distinct. Leg tarsal organs capsulate ( Figs 9D–F , 31A–E ; diameter 2.0–4.5 µm, diameter of opening 0.7–1.4 µm). Main tarsal claws with ~9–11 tines ( Figs 10F , 22F , 30F ). Claws of tarsus 4 different from others (tines more directed towards distal; Fig. 10G ). Female In general, similar to males but sternum without pair of anterior humps, chelicerae without stridulatory files ( Figs 8D , 13B , 27G ), cheliceral fangs unmodified, clypeus never strongly protruding ( Fig. 27D ) and without sclerotized rim, and palpal tarsal organ less strongly raised ( Figs 14F , 29F ; see also fig. 76 in Huber 2000 ) and slightly smaller (diameter 4.0–4.3 µm, diameter of opening 1.0–1.2 µm). Legs slightly shorter than in males (male / female tibia 1 length: ~1.0–1.2); tibia 1 length 0.37 – 0.74. Spinnerets as in male ( Figs 6B , 13F , 22C, D , 28C ). Epigynum with simple semicircular anterior plate, weakly protruding, posteriorly straight or indented medially ( Figs 6E , 20F , 28D ); posterior plate short and simple, with or without indistinct median division. Internal genitalia ( Figs 11 , 16 , 24 , 32 ) very simple, apparently without pore plates; with large membranous structure (with or without median membranous process), either directed towards posterior and covered by posterior epigynal plate or directed towards anterior and covered by anterior epigynal plate. Relationships . Molecular (UCE) data (G. Meng, L. Podsiadlowski, B.A. Huber, unpubl. data) suggest that the closest known relative of Galapa is an undescribed species from Brazil , Piauí , Parque Nacional da Serra da Capivara. That species is known from a single male specimen that does not share any of the diagnostic genital characters of Galapa listed above. Together, these two clades are sister to Kambiwa + Pemona , two further South American genera. All of these together are sister of the southern South American genus Guaranita . Thus, Galapa is deeply nested within South American Ninetinae . Even though a NJ tree ( Fig. 1 ) is not supposed to reliably reflect phylogeny, it shows two splits worth mentioning. First, within Galapa , G. bella ( Galapagos ) is sister to the mainland species. Several morphological characters support this split: (1) Mainland species share a proximal ridge on the basis of the leg trichobothria; in G. bella , these bases are round, which is likely the plesiomorphic condition; (2) in mainland species, the male palpal tarsal organ has moved to the procursus, while in G. bella it has the plesiomorphic position on the tarsus; (3) in mainland species, the female internal genitalia are directed towards posterior, while in G. bella they are directed towards anterior, which is probably the plesiomorphic condition; (4) finally, body size and leg length are smaller in mainland species than in species from Galapagos (carapace width: ~0.4 vs. ~0.5; tibia 1 length:>0.60 versus <0.55); the plesiomorphic condition is unknown. Second, the Central American (Costa Rican) G. murphyi is nested within a group of mainland South American species. This position is supported by the loss of epiandrous spigots in G. murphyi and G. spiniphila , while G. bella and G. gabito share the plesiomorphic presence of four epiandrous spigots.