Galapa bella
Creators: name: Huber, Bernhard A.
name: Meng, Guanliang
name: García, Jimmy Cabra
name: Carvalho, Leonardo S.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Galapa
Galapa bella

description: Galapa bella (Gertsch & Peck, 1992)
Figs 6–11
Pholcophora bella Gertsch & Peck, 1992: 1190, figs 32–36 (♂ ♀).
Galapa bella — Huber 2000: 101, figs 381–384, 389. Huber & Acurio 2022: 195, fig. 7. Dederichs et al. 2022: 11, fig. 12 (sperm morphology).
Diagnosis (amendments; see Huber 2000). Distinguished from mainland South and Central American congeners by much larger distal bulbal apophysis (Fig. 7B), by anterior rather than posterior position of large membranous element in female internal genitalia (Fig. 11C, D), and by body size and leg length (carapace width:>0.45; tibia 1 length:>0.60); from mainland South American congeners also by subdistal rather than distal position of retrolateral-distal process on procursus (Fig. 7B); from G. murphyi also by simple rather than bifid retrolateral-distal process on procursus (Fig. 7B).
Redescription (amendments of Huber 2000, based on specimens reported in Huber & Acurio 2022)
Male carapace width 0.47–0.53. Distance PME-PME 45 µm; diameter PME 45 µm; distance PME-ALE 15 µm; distance AME-AME 15 µm; diameter AME 30 µm. Tibia 1 in four males (including holotype): 0.66, 0.67, 0.68, 0.74; diameters of leg femora 0.10, of leg tibiae: 0.06. Clypeus not more protruding than in female, without sclerotized rim. Sternum with pair of barely visible anterior humps near coxae 1 (~5 µm high, 20 µm diameter at basis). Gonopore with four epiandrous spigots arranged in two pairs (Fig. 6F). ALS with one strongly widened spigot, one long pointed spigot, and five cylindrical spigots, of which one is much wider than the others (Fig. 6C); PMS with two conical spigots (Fig. 6C); PLS without spigots. Chelicerae in general very similar to congeners (cf. Huber 2000: fig. 384), with curved process proximally on fang (Fig. 8A); with stridulatory files consisting of ~50 ridges, distances between ridges 1.5–1.6 µm throughout, without further fine subdivision (Fig. 8B). Palpal femur proximally with prolateral stridulatory pick (Fig. 8C); femur-patella joints strongly shifted towards prolateral side; tibia oval, with two trichobothria; tibia-tarsus joints barely shifted towards retrolateral side; palpal tarsal organ strongly raised (Fig. 9A–C), diameter 6.7 µm, diameter of opening 1.7 µm; procursus with pointed retrolateral-distal process directed towards proximal and dorsal (Fig. 7B); tip of dorsal process covered by dorsal flap of genital bulb (Fig. 7B) but not lodged in pocket as in South American congeners; genital bulb with large distal apophysis (Fig. 7B), apparently without retrolateral-dorsal process and ventral processes; sperm duct opening on prolateral-ventral side directly on bulb (Fig. 7H). Legs with round cuticular plates (Fig. 10A, B; diameter 4–5 µm) and rimmed pores (Fig. 10A–C; outer diameter 3.4–3.7 µm, diameter of opening 0.2 µm) apparently on all leg segments. Sexually dimorphic short vertical hairs present on tibiae 1 and 2 (Fig. 8E–H), length ~15 µm, diameter at basis 1.2 µm. Chemoreceptive hairs similar in size (length ~13 µm, diameter at basis 1.7 µm) but with side branch (Fig. 10F). Retrolateral trichobothrium of tibia 1 at 60%; prolateral trichobothrium absent on tibia 1. Leg tarsal organs capsulate (Fig. 9E, F; diameter 3.7–4.5 µm, diameter of opening 1.0–1.4 µm). Main tarsal claws with ~10–11 tines (Fig. 10F, G).
Female in general similar to male but sternum without anterior humps, chelicerae without stridulatory files (Fig. 8D), cheliceral fangs unmodified. Tibia 1 in two females: 0.65, 0.68 (Huber 2000). The female from Santa Cruz, near Canal de Itabaca, has longer legs (tibia 1: 0.78) and a CO1 distance to specimens from 1 km SW of Garrapatero beach of 8.8–9.0%. It may in fact represent a different species. Spinnerets as in male (Fig. 6B, D). Epigynum (Figs 6E, 11A, B) with simple semicircular anterior plate, weakly protruding, posteriorly not indented medially; posterior plate short and simple, without median division. Internal genitalia (Fig. 11C, D) very simple, apparently without pore plates; membranous bilobed structure with short median process, covered by anterior epigynal plate (not by posterior epigynal plate as in South American congeners).
Distribution. Known from several localities on Santa Cruz Island, Galápagos. The single female reported from Santa Cruz, Islote Venecia (~ 0.5178°S, 90.4760°W), by Gertsch & Peck (1992), may also represent this species rather than G. baerti. The species has been claimed to be present on Genovesa and Pinta Islands (Baert et al. 2008; Baert 2013, 2014) but without specimen and collection data, so these records are here considered dubious.
Natural history. At the type locality (Charles Darwin Research Station), the species seems to have been replaced by the introduced Modisimus culicinus (Simon, 1893) (Huber & Acurio 2022). The specimens newly collected in 2019 (listed in Huber & Acurio 2022) were found in very dry and exposed habitats near the sea, under rocks and small stones and pebbles (Fig. 5A, B). At both localities (near Garrapatero beach and near Canal de Itabaca), the spiders occupied the drier upper layer of stones, while Anopsicus banksi (Gertsch, 1939) was found in the deeper, slightly more humid layers. The spiders ran very quickly when disturbed.
description: Published as part of Huber, Bernhard A., Meng, Guanliang, García, Jimmy Cabra & Carvalho, Leonardo S., 2024, Thriving in dry conditions: on the Neotropical spider genus Galapa (Araneae: Pholcidae), pp. 301-347 in Zootaxa 5419 (3) on pages 311-317, DOI: 10.11646/zootaxa.5419.3.1, http://zenodo.org/record/10791767