Pholcus tambunan Huber

Bernard A. Huber, Joseph K. H. Koh, Amir-Ridhwan M. Ghazali, Kamil A. Braima, Olga M. Nuñeza, Charles Leh Moi Ung & Booppa Petcharad, 2016, New leaf- and litter-dwelling species of the genus Pholcus from Southeast Asia (Araneae, Pholcidae), European Journal of Taxonomy 200, pp. 1-45 : 25-30

Pholcus tambunan Huber sp. nov.

urn:lsid:zoobank.org:act:5FD747F9-A402-4C77-BFC0-B26BDCDB10B5

Figs 93–96 , 101–119 , 125–127

Diagnosis

Easily distinguished from most similar known relative ( P. bario Huber sp. nov.) by morphology of male palps ( Figs 101–102 ; shorter trochanter apophysis; wider femur; distinctive structures on tip of procursus), by different shapes of frontal cheliceral apophyses ( Fig. 103 ), and by shorter epigynal scape ( Figs 104 , 119 ).

Etymology

The species is named for Tambunan , the town close to the type locality; noun in apposition.

Material examined

Holotype

MALAYSIA-BORNEO: ♂, ZFMK ( Ar 15710 ), Sabah, Crocker Range between Kota Kinabalu and Tambunan , S-slope, forest along river (5.783°N, 116.339°E), 1430–1480 m a.s.l., on underside of leaf, 3 Aug. 2014 (B.A. Huber, S.B. Huber) .

Other material

MALAYSIA-BORNEO: 4 ♂♂, 3 ♀♀, ZFMK ( Ar 15711–12 ) , and 1 ♂, 1 ♀, SMK, same data as holotype ; 2 ♀♀, 3 juvs, in absolute ethanol, ZFMK ( Bor 172 ), same data . 2 ♂♂, 1 ♀, ZFMK ( Ar 15713 ), Crocker Range between Kota Kinabalu and Tambunan , N-slope, forest along river (5.834°N, 116.336°E), 1600 m a.s.l., undersides of leaves, 3 Aug. 2014 (B.A. Huber, S.B. Huber) ; 2 ♀♀, in absolute ethanol, ZFMK ( Bor 167 ), same data ; 2 ♂♂, 14 ♀♀, 1 juv., ZFMK ( Ar 15714–15 ), Mt. Kinabalu, forest along Silau Silau Trail (6.010– 6.017°N, 116.537– 116.543°E), 1550–1650 m a.s.l., on undersides of leaves, 6 Aug. 2014 (B.A. Huber, S.B. Huber) ; 4 ♀♀, 2 juvs, in absolute ethanol, ZFMK ( Bor 212 ), same data ; 1 ♂, 1 ♀, AMNH, Mt. Kinabalu , 1550 m a.s.l., 24 Jul. 1980 (C.L. & P.R. Deeleman) ; 1 ♂, RMNH, same data but river trail, 27 Apr. 1979 ; 3 ♂♂, 1 ♀, RMNH, same data but river trail, 21–25 Aug. 1980 ; 1 ♂, 1 ♀, RMNH, same data but 1–5 May 1991 .

Assigned tentatively

MALAYSIA-BORNEO: 1 ♀ (abdomen only), RMNH, Sepilok, 25 km E Sandakan [5.87°N, 117.94°E], 1 Oct. 1980 (P. Zborowski) .

Description

Male (holotype)

MEASUREMENTS. Total body length 4.1, carapace width 1.0. Leg 1: 37.3 (8.8 + 0.4 + 8.8 + 17.0 + 2.3), tibia 2: 5.6, tibia 3: 3.3, tibia 4: 5.0; tibia 1 L/d: 100. Distance PME-PME 450 µm, diameter PME 130 µm, distance PME-ALE ~35 µm; no trace of AME.

COLOR. Carapace whitish with dark median mark widening anteriorly and including ocular area and clypeus in upper part and laterally; sternum whitish; legs pale ochre-yellow with dark brown patellae and tibia-metatarsus joints; abdomen pale ochre-gray with black marks dorsally and laterally, monochromous ventrally.

BODY. Habitus as in Figs 93–94 ; ocular area slightly raised, each triad on additional short stalk directed towards lateral ( Fig. 106 ); carapace without median furrow; clypeus unmodified; sternum wider than long (0.70/0.54), unmodified. Gonopore with four epiandrous spigots ( Fig. 1 16 ).

CHELICERAE. As in Fig. 103 , with distinctive pair of frontal apophyses (large flat plates, distally drawn out into small tip; Fig. 108 ) and rounded lateral humps; without modified hairs; without stridulatory ridges.

PALPS. As in Figs 101–102 ; coxa unmodified; trochanter with strong ventral apophysis; femur cylindrical, with indistinct prolateral hump proximally; tibia with distinctively elevated dorso-distal rim; tarsal organ as in Fig. 114 ; procursus with strong ventral ‘knee’, with distinctive small prolateral sclerotized process at 1/3 length, distal half with large whitish area retrolaterally, tip complex with distinctive sclerites ( Figs 109, 110 ); bulb elongated, long appendix with distinctive prolateral process provided with small teeth, further teeth along ventral rim, proximal processes of appendix ‘guiding’ embolus between them ( Fig. 111 ); embolus long and weakly sclerotized, tip as in Fig. 115 .

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium on tibia 1 at 2%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 pseudosegments not seen in dissecting microscope. Tarsus 4 comb-hairs as in Fig. 113 .

Male (variation)

Tibia 1 in 7 other males: 8.2–9.3 (mean 8.6).

Female

In general similar to male ( Fig. 96 ) but carapace mark only in posterior half; ocular area dark as in male but clypeus light. Eye triads much closer together than in male ( Fig. 107 ; PME-PME distance: 265 µm). Dark marks on abdomen less distinct or even absent. Tibia 1 in 18 females: 6.2–7.2 (mean 6.7). Epigynum weakly sclerotized ( Fig. 125 ), wide transversal plate with scape directed towards anterior ( Fig. 104 ); dark internal arch and lateral posterior structures visible through cuticle; internal genitalia as in Figs 105 , 126, 127 , with pair of highly distinctive three-layered telescopic tubes. ALS with one large widened, one pointed, and six smaller cylindrically-shaped spigots ( Fig. 118 ). The female from Sepilok is assigned tentatively because no male is known from this locality.

Natural history

The spiders were found on the undersides of live leaves about 50–200 cm above the ground. They built barely visible silk platforms directly attached to the leaf surface rather than the ‘usual’ pholcid domes. Several webs were occupied (in addition to the spider) by large numbers of Diptera (probably Cecidomyiidae , not collected).

Distribution

Known from three localities in northeastern Borneo (Sabah) ( Fig. 1 ; but note that the single specimen from Sepilok is assigned tentatively).

Figures

Fig. 1. Known distributions of the Pholcus ethagala group (Malay Peninsula and Sumatra; Sri Lankan species not shown), of the P. tambunan group (Borneo) and of the P. domingo group (Philippines).

Figs 2 – 9. Live specimens. 2 – 3. Pholcus phui Huber, 2011, Hala Bala, ♂ and ♀ with egg-sac. 4 – 7. P. tanahrata Huber sp. nov., Cameron Highlands, ♂, penultimate ♂, and ♀. 8 – 9. P. uludong Huber sp. nov., Ulu Dong, ♂ and ♀.

Figs 10 – 14. Pholcus tanahrata Huber sp. nov. (ZFMK, Ar 15692). 10 – 11. Left male palp, prolateral and retrolateral views. 12. Male chelicerae, frontal view. 13 – 14. Cleared female genitalia, ventral and dorsal views. Scale bars: 10 – 11, 13 – 14 = 0.5 mm; 12 = 0.3 mm.

Figs 15 – 19. Pholcus uludong Huber sp. nov. (ZFMK, Ar 15695 – 96). 15 – 16. Left male palp, prolateral and retrolateral views; arrow points at uncus-like process of proximal bulbal sclerite. 17. Male chelicerae, frontal view. 18 – 19. Cleared female genitalia, ventral and dorsal views. Scale bars: 15 – 16, 18 – 19 = 0.5 mm; 17 = 0.3 mm.

Figs 93 – 100. Live specimens. 93 – 96. Pholcus tambunan Huber sp. nov., Crocker Range, ♂, penultimate ♂, and ♀ with egg-sac. 97 – 100. P. bario Huber sp. nov., Bario, ♂ and ♀ with egg-sac.

Figs 101 – 105. Pholcus tambunan Huber sp. nov. (ZFMK, Ar 15711 – 12). 101 – 102. Left male palp, prolateral and retrolateral views. 103. Male chelicerae, frontal view. 104 – 105. Cleared female genitalia, ventral and dorsal views. Scale bars: 101 – 102, 104 – 105 = 0.5 mm; 103 = 0.3 mm.

Figs 106 – 113. Pholcus tambunan Huber sp. nov., SEM micrographs (ZFMK, Ar 15711, 15715). 106 – 107. Male and female prosomata, frontal views. 108. Right male cheliceral apophysis. 109. Right procursus, retrolateral view. 110. Left procursus, prolateral view. 111. Proximal parts of left appendix and embolus. 112. Male ocular area, dorsal view. 113. Comb-hairs on male tarsus 4. Scale bars: 106 – 107, 112 = 200 µm; 108 = 20 µm; 109 – 111 = 100 µm; 113 = 10 µm.

Figs 114 – 119. Pholcus tambunan Huber sp. nov., SEM micrographs (ZFMK, Ar 15711, 15715). 114. Male left palpal tarsal organ. 115. Tip of left embolus. 116. Male gonopore. 117. Base of trichobothrium on male palpal tibia. 118. Female ALS. 119. Epigynum, ventral view. Scale bars: 114, 118 = 20 µm; 115 = 50 µm; 116 = 40 µm; 117 = 8 µm; 119 = 200 µm.

Figs 125 – 130. Epigyna, ventral views, and cleared female genitalia, ventral and dorsal views. 125 – 127. Pholcus tambunan Huber sp. nov. (ZFMK, Ar 15712). 128 – 130. P. bario Huber sp. nov. (ZFMK, Ar 15718).