Pholcus Walckenaer, 1805

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), European Journal of Taxonomy 225, pp. 1-34 : 3-5

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 ).

Figures

Figs 12 – 15. Pholcus olangapo Huber, sp. nov., ZFMK Ar 15497 – 98. 12. Male prosoma, frontal view. 13, 15. Male ocular horns with modiFed and ‘ glued’ or ‘ waxed’ hairs, frontal and lateral views. 14. Female prosoma, frontal view. Scale lines: 12, 14 = 400 µm; 13 = 50 µm; 15 = 60 µm.

Figs 63 – 70. Pholcus baguio Huber, sp. nov., ZFMK Ar 15507. 63. Male prosoma, frontal view. 64. Male ocular area, frontal (slightly dorsal) view. 65 – 66. Male ocular horns and modiFed hairs. 67. Male ocular area, dorsal view. 68. Male left palpal tarsal organ. 69. Right male palpal trochanter and procursus, retrolatero-dorsal view. 70. Left procursus, distal view. Scale lines: 63 = 500 µm; 64 = 300 µm; 65 = 80 µm; 66, 70 = 100 µm; 67, 69 = 200 µm; 68 = 30 µm.

Figs 77 – 84. Pholcus arayat Huber, 2011, ZFMK Ar 15509. 77. Male prosoma, frontal view. 78. Male ocular horns and modiFed hairs. 79. Female prosoma, frontal view. 80. Male ocular area, dorsal view. 81. Right genital bulb, prolateral view. 82. Left male palpal trochanter and procursus, dorsal view (arrow points at biFd process). 83 – 84. Tip of right procursus, prolateral and prolatero-distal views (arrows point at biFd process). Scale lines: 77, 79 = 300 µm; 78 = 50 µm; 80 – 82 = 200 µm; 83 – 84 = 100 µm.

Figs 91 – 98. Pholcus pagbilao Huber, 2011, ZFMK Ar 15515 – 16. 91. Male prosoma, frontal view. 92. Male ocular horns and modiFed hairs. 93. Female prosoma, frontal view. 94 – 95. Male ocular area, dorsal and latero-dorsal views. 96. Male distal cheliceral apophysis (arrows point at modiFed hairs). 97. Left procursus, dorsal view (arrow points at semitransparent process). 98. Left genital bulb, prolateral view. Scale lines: 91, 93 = 400 µm; 92 = 60 µm; 94 – 95, 98 = 200 µm; 96 = 20 µm; 97 = 100 µm.

Figs 3 – 6. Live specimens, Pholcus olangapo Huber, sp. nov., Pamulaklakin Forest Trail. 3 – 4. ♁ and ♀ in their natural habitat. 5 – 6. ♁ and ♀ photographed on a dead leaf.

Figs 36 – 39. Live specimens. 36 – 37. Pholcus mulu Huber, sp. nov., ♁, Gunung Mulu. 38 – 39. Pholcus kawit Huber, sp. nov., ♁ and ♀, Mt. Matutum.

Figs 50 – 53. Live specimens. 50 – 52. Pholcus baguio Huber, sp. nov., ♁, ♀, and ♀ with egg-sac and emerging juveniles, Mt. Kabuyao. 53. Pholcus arayat Huber, 2011, ♁, Pamulaklakin Forest Trail.

Figs 54 – 57. Live specimens. 54. Pholcus arayat Huber, 2011, ♀, Pamulaklakin Forest Trail. 55 – 57. Pholcus pagbilao Huber, 2011, ♁ from Loboc (55), ♁ from Mt. Banahaw (56), and ♀ with egg-sac from Loboc (57).

Figs 16 – 23. Pholcus olangapo Huber, sp. nov., ZFMK Ar 15497 – 98. 16. Right genital bulb, prolateral view. 17. Left tarsus and procursus, dorsal view (asterisk marks prolatero-dorsal process of procursus). 18. Tip of left procursus, dorsal view. 19. Female spinnerets. 20. Male cheliceral apophysis (arrows point at modiFed hairs). 21. Male ALS. 22. Male gonopore. 23. Epigynum. Scale lines: 16, 23 = 200 µm; 17 = 300 µm; 18 = 100 µm; 19 = 70 µm; 20 – 21 = 20 µm; 22 = 40 µm.

Figs 71 – 76. Pholcus baguio Huber, sp. nov., ZFMK Ar 15507 – 08. 71 – 72. Left genital bulb, prolateral and prolatero-distal views. 73. Male distal cheliceral apophysis (arrows point at modiFed hairs). 74. Male ALS. 75. Epigynum. 76. Female ALS and PMS. Scale lines: 71 – 72, 75 = 200 µm; 73 – 74, 76 = 20 µm.

Figs 85 – 90. Pholcus arayat Huber, 2011, ZFMK Ar 15509. 85. Male distal cheliceral apophysis (arrows point at modiFed hairs). 86. Male gonopore. 87. Male tarsus 4 comb-hairs. 88. Male ALS. 89. Epigynum. 90. Female ALS. Scale lines: 85, 87 – 88, 90 = 20 µm; 86 = 50 µm; 89 = 200 µm.

Figs 99 – 102. Pholcus pagbilao Huber, 2011, ZFMK Ar 15515 – 16. 99. Male gonopore. 100. Male ALS. 101. Epigynum. 102. Female ALS. Scale lines: 99 = 50 µm; 100, 102 = 20 µm; 101 = 200 µm.

Figs 7 – 11. Pholcus olangapo Huber, sp. nov., ZFMK Ar 15497 – 98. 7 – 8. Left male palp, prolateral and retrolateral views (asterisk marks prolatero-dorsal process of procursus). 9. Male chelicerae, frontal view. 10 – 11. Cleared female genitalia, ventral and dorsal views. Scale lines: 7 – 8 = 1 mm; 9 – 1 1 = 0.5 mm.

Figs 24 – 35. Epigyna, ventral views, and cleared female genitalia, ventral and dorsal view. 24 – 26. Pholcus olangapo Huber, sp. nov., ZFMK Ar 15498. 27 – 29. Pholcus mulu Huber, sp. nov., ZFMK Ar 15502. 30 – 32. Pholcus kawit Huber, sp. nov., ZFMK Ar 15505. 33 – 35. Pholcus baguio Huber, sp. nov., ZFMK Ar 15508.

Figs 1 – 2. Known distributions of the two subgroups of the Pholcus bicornutus species group.

Figs 40 – 44. Pholcus mulu Huber, sp. nov., ZFMK Ar 15501 – 02. 40 – 41. Left male palp, prolateral and retrolateral views. 42. Male chelicerae, frontal view. 43 – 44. Cleared female genitalia, ventral and dorsal views. Scale lines: 40 – 41 = 1 mm; 42 – 44 = 0.5 mm.

Figs 45 – 49. Pholcus kawit Huber, sp. nov., ZFMK Ar 15505. 45 – 46. Left male palp, prolateral and retrolateral views (arrow points at ventral cavity of tibia). 47. Male chelicerae, frontal view. 48 – 49. Cleared female genitalia, ventral and dorsal views. Scale lines: 45 – 46 = 1 mm; 47 – 49 = 0.5 mm.