Pholcus Walckenaer 1805
Creators: name: Huber, Bernhard A.
name: Nuñeza, Olga M.
name: Leh Moi Ung, Charles
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Pholcus

description: Pholcus Walckenaer, 1805
Pholcus Walckenaer, 1805: 80. Type species by (assumed) monotypy: Aranea phalangioides Fuesslin, 1775.
Pholcus – Huber 2011a: 124–126.
Pholcus bicornutus species group
Diagnosis
Large, long-legged Pholcus (body length ~5–8, male leg 1 length: ~40–60) with cylindrical abdomen, eight eyes, and rather dark coloration; distinguished from similar insular Southeast Asian species groups (P. gracillimus group; P. ancoralis group; cf. Huber 2011a) by male ocular area with unique pair of processes, each carrying brush of hairs (Figs 12–13, 63–67, 78, 92) (P. ancoralis group also with horns but without brushes of hairs), by male palpal tibia very large relative to femur (in contrast to P. ancoralis species group), and by paired anterior marks in dorsal abdominal pattern (Figs 3, 36, 50, 55; unpaired in P. gracillimus and P. ancoralis groups).
Description – amendments
The original description of the species group (Huber 2011a) is still largely valid. The following are minor updates and additions: body length ~5–8, carapace width 1.3–1.8. Male distal cheliceral apophyses provided with 2–3 modified hairs each (Figs 20, 73, 85, 96). Tibia 1 length in males ~9.5–16.0, in females ~7.5–14.0; male tibia 1 L/d ~65–80; legs either with curved hairs (tibiae and metatarsi 1–2; P. bicornutus, P. olangapo sp. nov.) or without curved hairs (other species). Abdomen cylindrical, with cuticular color pattern dorsally (also in P. bicornutus), anterior element always paired. ALS with one widened, one pointed, and variable number of smaller spigots: either six cylindrically-shaped spigots of ‘usual’ size (i.e., ~3–8 µm wide and ~5–8 µm long; Figs 19, 21, 100, 102), or only three to five very small conical spigots (i.e., ~1.5–3 µm wide and ~3–6 µm long; Figs 74, 76, 88, 90).
Composition
The eight species assigned to this group are here divided into two operational sub-groups:
(1) A sub-group of two species (P. bicornutus Simon, 1892; P. olangapo sp. nov.), sharing the following similarities: absence of male bulbal appendix (Fig. 7); procursus with hinged distal element and with distinctive prolatero-dorsal process (Figs 8, 17); male palpal tibia ventrally unmodified; hairs of ocular processes ‘glued’ or ‘waxed’ together (Figs 12–13, 15); epigynum with small epigynal plate and large membranous area in front of plate (Fig. 24); proximal lateral processes on male chelicerae large (Fig. 9); and presence of curved hairs on tibiae and metatarsi 1–2. A third (unnamed) species occurs on Negros Island (“sp. Phi 190” in Fig. 1; 1 ♀, 1 juv. from Twin Lakes National Park, in ZFMK).
(2) A sub-group of six species (P. arayat Huber, 2011; P. mulu sp. nov.; P. baguio sp. nov.; P. kawit sp. nov.; P. pagbilao Huber, 2011; P. schawalleri Yao et al., 2014), sharing the alternative character states: presence of male bulbal appendix (Figs 40, 45); procursus without hinged distal element and without dorsal process (Figs 41, 46); male palpal tibia with small ventral cavity to accommodate proximal bulbal sclerite in resting position (arrow in Fig. 45); hairs of ocular processes not ‘glued’ or ‘waxed’ together (Figs 65–66, 78); epigynum with large epigynal plate (Figs 27, 30, 33); proximal lateral processes on male chelicerae small (Figs 42, 47); no curved hairs on legs. A possible further species occurs on Mindanao, but it is represented by two juvenile specimens only (“sp. Phi 254” in Fig. 2; from Marilog Distr., Baganihan, in ZFMK). The undescribed species from Mt. Apo mentioned in Huber (2011a: 315) was restudied and found to belong to another species group.
Natural history
Seven of the eight named species were observed in the field. They occupied a variety of microhabitats, ranging from caves (close to the ground; P. bicornutus) and wet rock walls (P. olangapo sp. nov.) to dark sheltered spaces among rocks (P. mulu sp. nov., P. baguio sp. nov., P. pagbilao), large holes at tree bases (P. kawit sp. nov.), abandoned buildings (P. pagbilao), and open space among vegetation exposed to direct sunlight (P. arayat). Webs mainly consisted of a domed sheet with a diameter of up to ~ 50 cm (P. mulu sp. nov.), but were much smaller in the rock-dwelling P. olangapo sp. nov. (~ 15 cm). In P. baguio sp. nov., webs were connected to each other and formed large communal structures up to 2 m in length. When disturbed, most species were observed to run toward the periphery of the web, seeking shelter at the substrate rather than staying and whirling in the web.
Distribution
The Pholcus bicornutus group is largely restricted to the Philippines, with only one species in NE Borneo (Figs 1–2).
description: Published as part of Huber, Bernhard A., Nuñeza, Olga M. & Leh Moi Ung, Charles, 2016, The Philippine hair wax spiders and their relatives: revision of the Pholcus bicornutus species group (Araneae, Pholcidae), pp. 1-34 in European Journal of Taxonomy 225 on pages 3-5, DOI: 10.5852/ejt.2016.225, http://zenodo.org/record/830814