Pholcus ubin Huber

Berhard A. Huber, Booppa Petchard, Charles Leh Moi Ung, Joseph K. H. Koh & Amir R. M. Ghazali, 2016, The Southeast Asian Pholcus halabala species group (Araneae, Pholcidae): new data from field observations and ultrastructure, European Journal of Taxonomy 190, pp. 1-55 : 10-12

Pholcus ubin Huber , sp. nov.

urn:lsid:zoobank.org:act:5EC32BD5-FE22-45DE-A5EB-7659D61FFC03

Figs 7–8 , 29–33 , 90–92

Diagnosis

Easily distinguished from putatively closest known relatives (other species in the halabala core group) by morphology of male palps ( Figs 29–30 ; procursus with heavily sclerotized dorsal process distally; shapes of uncus and appendix) and by female internal genitalia ( Figs 32–33 ; triangular pore plates).

Etymology

The species name is derived from the type locality; noun in apposition.

Type material

SINGAPORE: holotype, ♂, ZFMK ( Ar 15010 ), Pulau Ubin , degraded forest near park headquarters (1°24.2' N, 103°58.2' E), 20 m a.s.l., on leaves, 16 Feb. 2015 (B.A. Huber, J. Koh, D. Court) .

Other material examined

SINGAPORE: 2 ♂♂, 3 ♀♀, ZFMK ( Ar 15011 ), same data as holotype ; 2 ♀♀, 3 juvs , in absolute ethanol, ZFMK ( Mal 232 ), same data .

MALAYSIA-BORNEO: 1 ♂, RMNH, Sabah , Gaya Island (6° 00.90' N, 116° 01.17' E), 22 Aug. 2009 (A. Floren) .

Description

Male (holotype)

MEASUREMENTS. Total body length 4.1, carapace width 1.0. Leg 1: 30.4 (7.3 + 0.4 + 7.2 + 14.2 + 1.3), tibia 2: 4.7, tibia 3: 2.7, tibia 4: 3.9; tibia 1 L/d: 86. Distance PME-PME 220 µm, diameter PME 95 µm, distance PME-ALE ~35 µm; distance AME-AME 35 µm; diameter AME 60 µm.

COLOR. Carapace ochre-yellow with brown pattern of radiating marks posteriorly, in live specimens with reddish color in median area between posterior marks ( Fig. 7 ); ocular area and clypeus not darkened; sternum with some dark marks posteriorly; legs ochre-yellow with dark brown patellae and tibiametatarsus joints; abdomen pale ochre-gray with small black and white marks dorsally and laterally, monochromous ventrally.

BODY. Habitus as in Fig. 7 ; ocular area slightly raised, with brushes of ~10 stronger hairs behind each PME; carapace without median furrow; clypeus unmodified; sternum wider than long (0.62/0.40), unmodified.

CHELICERAE. As in Fig. 31 , with pair of frontal apophyses provided with two modified hairs each and rounded lateral processes.

PALPS. As in Figs 29–30 ; coxa unmodified; trochanter with retrolatero-ventral apophysis; femur with small retrolateral apophysis proximally; tibia very large; tarsus with dorsal elongation carrying subdistal tarsal organ; procursus with prominent ventral ‘knee’, with distinctive heavily sclerotized dorsal process distally (arrow in Fig. 30 ); bulb oval, with distinctive uncus and appendix; weakly sclerotized embolus with subdistal fringed side branch (hidden by appendix in Fig. 29 ).

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium on tibia 1 at 5%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 with ~20 pseudosegments (only distally ~15 fairly distinct).

Male (variation)

Tibia 1 in 2 other males: 6.1, 7.3.

Female

In general similar to male ( Fig. 8 ), but without stronger hairs behind PME; sternum mostly dark with some small light marks; eye triads closer together than in male (PME-PME distance: 185 µm). Tibia 1 in 3 females: 5.8, 5.9, 6.1. Epigynum weakly sclerotized whitish plate ( Fig. 90 ), anterior internal arch visible through cuticle, posterior margin laterally slightly more sclerotized; with median ‘knob’ ( Figs 32 , 90–91 ); internal genitalia as in Figs 33 and 92 .

Natural history

All Pulau Ubin specimens were found in a highly degraded patch of forest near park headquarters, while no specimen was found in a well preserved forest about 3.3 km WNW. Most specimens were collected by beating of branches, but some were observed in their flat resting position on the leaves.

Distribution

Known from two localities in Singapore and Gaya Island ( Sabah ) respectively ( Fig. 17 ).

Figures

Fig. 17. Known distribution of the core group of the Pholcus halabala species group.

Figs 1 – 8. Live specimens, Pholcus halabala Huber, 2011 (1 – 6) and Ph. ubin Huber, sp. nov. (7 – 8). 1. ♂ from MacRitchie, Singapore. 2. ♂ from Gunung Jerai, Malaysia. 3. ♀ with egg-sac from Gunung Liang, Malaysia. 4. Juvenile in web with silk tufts, Upper Selatar, Singapore. 5. ♀ with egg-sac from Hala Bala, Thailand. 6. ♀ with egg-sac from Ulu Dong, Malaysia. 7 – 8. ♂ and ♀ from Pulau Ubin, Singapore.

Figs 29 – 33. Pholcus ubin Huber, sp. nov., ZFMK Ar 15011. 29 – 30. Left male palp, prolateral and retrolateral views (arrow points at distinctive dorsal process; asterisk marks dorsal elongation of male palpal tarsus). 31. Male chelicerae, frontal view. 32 – 33. Cleared female genitalia, ventral and dorsal views. Abbreviations: a = appendix; b = genital bulb; e = embolus; p = procursus; u = uncus. Scale lines: 0.3 mm (31); 0.5 mm (29 – 30, 32 – 33).

Figs 90 – 101. Female genitalia, untreated in ventral view, cleared in ventral and dorsal views. 90 – 92. Pholcus ubin Huber, sp. nov. 93 – 95. Ph. lintang Huber, sp. nov. 96 – 98. Ph. kuhapimuk Huber, sp. nov. 99 – 101. Ph. khaolek Huber, sp. nov.