Pholcus barisan 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 : 21-25

Pholcus barisan Huber sp. nov.

urn:lsid:zoobank.org:act:20779D81-A780-4FBD-92F6-78BD201FE319

Figs 63–66 , 72–76 , 80 , 90–92

Diagnosis

Easily distinguished from most similar known relatives (representatives of the P. ethagala group on the Malay Peninsula) by morphology of male palps ( Figs 72–73 ; very long dorsal process of procursus; relative straight male palpal trochanter apophysis similar to P. uludong Huber sp. nov. and P. phui but shorter; shape of relatively small appendix), by modified male clypeus (pair of small dark processes; Fig. 80 ), by male eye stalks directed more towards lateral ( Fig. 80 ), and by details of female internal genitalia ( Figs 75, 76 ; anterior undulating sclerite; large posterior semicircular structure).

Etymology

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

Material examined

Holotype

INDONESIA: ♂, ZFMK ( Ar 15708 ), Sumatra, Lampung, Bukit Barisan (5.528°S, 104.424°E), 550– 600 m a.s.l., forest near road, leaf litter, 24 Oct. 2009 (S. Sutono) .

Other material

INDONESIA: 6 ♀♀, 3 juvs, ZFMK ( Ar 15709 ), same data as holotype ; 4 ♀♀, 1 juv., in absolute ethanol, ZFMK ( Ind 153 ), same data .

Description

Male (holotype)

MEASUREMENTS. Total body length 3.3, carapace width 0.9. Leg 1: 33.2 (7.6 + 0.4 + 7.7 + 15.6 + 1.9), tibia 2: 4.5, tibia 3: 2.6, tibia 4: 4.0; tibia 1 L/d: 96. Distance PME-PME 510 µm, diameter PME 100 µm, distance PME-ALE ~30 µm; AME absent.

COLOR. Carapace pale ochre-yellow with large dark brown mark posteriorly, dark median line, ocular area, stalks and clypeus also dark brown; irregular black marks in place of AME; sternum whitish; legs ochre-yellow with darker brown to black patellae and tibia-metatarsus joints; abdomen ochre-gray with some darker marks dorsally and laterally.

BODY. Habitus as in Figs 63–64 ; ocular area raised, each triad on long stalk directed laterad and dorsad ( Fig. 80 ); carapace without median furrow; clypeus with pair of small dark processes at rim; sternum wider than long (0.60/0.53), unmodified.

CHELICERAE. As in Fig. 74 , with single pair of frontal proximal apophyses; without distal modification; without stridulatory ridges.

PALPS. As in Figs 72–73 ; coxa with indistinct ventral hump; trochanter with very long almost straight retrolatero-ventral apophysis and small retrolateral process; femur with indistinct retrolateral hump; tarsus without dorsal elongation; procursus complex, proximal part with distinctive dorsal process forming retrolateral groove distally, ventral side heavily sclerotized, dorsal side semitransparent; hinged distal part with large prolatero-dorsal flap and weakly sclerotized prolateral process lying parallel to procursus; bulb with rather simple appendix, long slender embolus, without uncus.

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium on tibia 1 at 3%; prolateral trichobothrium absent on tibia 1, present on other tibiae; tarsus 1 pseudosegments very indistinct, apparently irregular.

Female

In general similar to male ( Figs 65–66 ) but eye triads not on stalks and much closer together than in male (PME-PME distance: 240 µm); dark posterior mark on carapace smaller than in male, without median dark line on carapace; with pair of small black marks in area of AME (but without lenses); clypeus unmodified and only in upper third dark brown. Tibia 1 in 6 females: 6.0–6.9 (mean 6.4). Some females (and juveniles) with laterally strongly widened abdomen ( Fig. 65 ). Epigynum weakly sclerotized (Fig. 90), with small ‘knob’ at posterior rim ( Fig 75 ); internal anterior arc undulating, visible through cuticle; internal genitalia as in Figs 76 , 91–92.

Natural history

All specimens were found under large dead leaves on the ground. They hung in domed sheet webs closely attached to the leaf surface. They barely moved when disturbed and were not seen to vibrate.

Distribution

Known from type locality in Sumatra only ( Fig. 1 ).

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 59 – 66. Live specimens. 59 – 62. Pholcus bukittimah Huber sp. nov., Dairy Farm, ♂, penultimate ♂, and ♀ with partly parasitized egg-sac. 63 – 66. P. barisan Huber sp. nov., Bukit Barisan, ♂ and ♀♀ with variably expanded abdomens.

Figs 72 – 76. Pholcus barisan Huber sp. nov. (ZFMK, Ar 15708 – 09). 72 – 73. Left male palp, prolateral and retrolateral views. 74. Male chelicerae, frontal view. 75 – 76. Cleared female genitalia, ventral and dorsal views. Scale bars: 72 – 73, 75 – 76 = 0.5 mm; 74 = 0.3 mm.

Figs 77 – 80. Male prosomata, frontal views. 77. Pholcus tanahrata Huber sp. nov. 78. P. uludong Huber sp. nov. 79. P. bukittimah Huber sp. nov. 80. P. barisan Huber sp. nov.