Pholcus halabala

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: 3-7

publication ID

10.5852/ejt.2016.190

publication LSID

lsid:zoobank.org:pub:urn:lsid:zoobank.org:pub:BE92596B-62D9-46CD-8486-CF6B36C640B11

persistent identifier

http://treatment.plazi.org/id/7F7187D5-4E4E-702C-FDA0-C2ECCDFDFA7E

treatment provided by

Jeremy

scientific name

Pholcus halabala
status

 

Pholcus halabala  species group

Diagnosis

The core group of six species (see below) includes medium-sized, long-legged spiders (body length ~3–4, male leg 1 length ~30–40); distinguished from other species groups in Pholcus  by the combination of the following characters: elongate abdomen pointed dorso-posteriorly, with distinctive dorsal pattern of black and whitish or yellowish marks in life specimens ( Figs 1–16View Figs 1 – 8View Figs 9 – 16; similar only in Ph. sudhami Huber, 2011  , cf. Figs 54–56View Figs 49 – 56); eight eyes; male ocular area with conspicuous modified hairs (setae), which may appear as stiff bristles or stout curved spines, or both ( Figs 19, 23View Figs 18 – 28, 43View Figs 39 – 48); male chelicerae with proximal and distal apophyses, distal apophyses with two cone-shaped teeth (modified hairs) each ( Fig. 28View Figs 18 – 28); male bulb with uncus and appendix; procursus with distinctive dorsal flap ( Fig. 35View Figs 34 – 38; absent in Ph. erawan Huber, 2011  ); epigynum weakly sclerotized, with ‘knob’.

Description – amendments

The original description of the core group ( Huber 2011) is still largely valid. The following can be added: male eye triads on low humps ( Figs 18, 20View Figs 18 – 28, 43View Figs 39 – 48; i.e., not on short stalks as seen in Ph. krabi  group) and only slightly wider apart than female eye triads (1.2–1.5 ×); dorsal elongation of male palpal tarsus usually short and conical (asterisk in Fig. 30View Figs 29 – 33), long in Ph. erawan Huber, 2011  (fig. 1467 in Huber 2011); procursus usually with dorsal flap, absent in Ph. erawan  ; tibia 1 in males ~6–9, in females ~6–8; male gonopore with four epiandrous spigots ( Figs 26View Figs 18 – 28, 44View Figs 39 – 48; confirmed in Ph. halabala  and Ph. erawan  ); ALS with eight spigots each (one widened, one pointed, and six smaller cylindrically shaped spigots of varying sizes, Figs 25View Figs 18 – 28, 45View Figs 39 – 48; confirmed in Ph. halabala  and Ph. erawan  ); web consists mostly of flat round platform closely attached to underside of leaf; web sometimes with large numbers of small silk tufts ( Figs 4View Figs 1 – 8, 16View Figs 9 – 16; confirmed for Ph. halabala  , Ph. erawan  and Ph. sepaku  ); female holds egg-sac under body rather than in front of it ( Figs 3, 5–6View Figs 1 – 8, 16View Figs 9 – 16; confirmed for Ph. halabala  , Ph. erawan  and Ph. sepaku  ).

Composition

The 13 species assigned to this group are here divided into two operational sub-groups: a core-group of six species for which the evidence for monophyly is considered to be strong ( Ph. erawan Huber, 2011  ; Ph. halabala Huber, 2011  ; Ph. lintang Huber  , sp. nov.; Ph. sabah Huber, 2011  ; Ph. sepaku Huber, 2011  ; Ph. ubin  sp. nov.); and a sub-group of seven species whose assignment is tentative [ Ph. elongatus (Yin & Wang, 1981)  ; Ph. exceptus Tong & Li, 2009  ; Ph. khaolek Huber  , sp. nov.; Ph. kuhapimuk Huber  , sp. nov.; Ph. pakse Huber, 2011  ; Ph. pyu Huber, 2011  ; Ph. sudhami Huber, 2011  ].

The composition of the group changes as follows: to the original core group consisting of three species ( Ph. halabala  ; Ph. sabah  ; Ph. sepaku  ) we add two newly described species ( Ph. ubin Huber  , sp. nov.; Ph. lintang  sp. nov.) as well as Ph. erawan  . The latter species was originally part of another problematic species group ( Pholcus quinquenotatus  group; Huber 2011: 290). It lacks the distinctive dorsal flap on the procursus that is present in the other five species of the core group, and the hairs in the male ocular area are not particularly strong, but it is moved into the core group because (1) it builds the same distinctive web closely attached to the leaf surface as the five other species; (2) webs are provided with facultative silk tufts like in Ph. halabala  and Ph. sepaku  (otherwise only known in the African genus Smeringopus Simon, 1890  ; Huber 2012); (3) females carry the egg-sac under the body like Ph. halabala  and Ph. sepaku  , which is unique among Pholcidae  ; (4) life specimens have an almost identical distinctive pattern of large whitish to yellowish and black spots on the abdomen, and on the carapace a pair of V-marks; and (5) the procursus is provided with a distinctive retrolateral distal pocket also present in Ph. halabala  ( Figs 21–22View Figs 18 – 28, 41View Figs 39 – 48). Preliminary molecular data (A. Valdez-Mondragón, B.A.

Huber & D. Dimitrov unpublished data), including all species of the core group except Ph. sepaku  (i.e., also Ph. erawan  ), strongly support the monophyly of this group. The RMNH has three further species of the core group from Sabah  ( Fig. 17View Fig. 17), but the specimens are poorly preserved and for this reason not formally described here.

In addition to this core group, we include in the Ph. halabala  group two further species that were previously part of the Pholcus quinquenotatus  group ( Ph. sudhami Huber, 2011  ; Ph. pakse Huber, 2011  ) as well as two newly described species ( Ph. kuhapimuk  sp. nov.; Ph. khaolek  sp. nov.).Again, preliminary molecular data (A. Valdez-Mondragón, B.A. Huber & D. Dimitrov unpublished data) strongly support a close relationship of these four species with the core group, and at least Ph. sudhami  and Ph. pakse  share some morphological similarities with the core group (carapace and abdomen pattern, male eye triads on low humps, large AME, male cheliceral apophyses with modified hairs), but no putative morphological synapomorphy is known that would support this close relationship. The microhabitat of these four species differs from the core group (rocks and tree roots rather than foliage); egg-sacs are carried in front of the body as in typical pholcids; webs were never seen to be provided with silk tufts. In addition, males of Ph. sudhami  and Ph. pakse  lack stronger hairs in the ocular area, and both species lack the bulbal appendix.

Three species originally assigned to the halabala  group are kept in the group simply for the lack of a better solution: Ph. pyu Huber, 2011  ; Ph. elongatus (Yin & Wang, 1981)  ; and Ph. exceptus Tong & Li, 2009  . Data on natural history and ultrastructure are not available for any of them, nor is any of them included in our preliminary molecular analysis (A. Valdez-Mondragón, B.A. Huber & D. Dimitrov unpublished data). We speculate that Ph. pyu  may in fact belong to this group, but the other two species are quite certainly misplaced. Pholcus elongatus  lacks AME; males in this species have short eye stalks and pointed cheliceral apophyses without modified hairs; females have a long epigynal scape. We speculate that the closest relatives of Ph. elongatus  are the Taiwanese species Ph. pingtung Huber & Dimitrov, 2014  and Ph. chengpoi Huber & Dimitrov, 2014  (six eyes; similar cheliceral apophyses; scape directed toward anterior). Pholcus exceptus  is a mysterious species with entirely reduced distal cheliceral apophyses.

Finally, five species originally included in the Pholcus halabala  group are transferred to new species groups (see below): Ph. andulau Huber, 2011  ; Ph. chiangdao Huber, 2011  ; Ph. khene Huber, 2011  ; Ph. kinabalu Huber, 2011  ; and Ph. satun Huber, 2011  .

Natural history

All six species of the core group were observed in the field. At most localities, abundances seemed very low. Surprisingly, several species were partly or exclusively found in degraded forests. All specimens seen during the day were tightly pressed against the undersides of mostly large leaves. Webs consisted mainly of round platforms with a diameter of about 10 cm; most of the platform was closely attached to the leaf surface. Small silk tufts ( Figs 4View Figs 1 – 8, 16View Figs 9 – 16) were observed in some webs of three species ( Ph. halabala  ; Ph. erawan  ; Ph. sepaku  ), but may occur in other species as well (very few specimens seen in other species). The same applies to the peculiar position in which egg-sacs are held by females: in Ph. halabala  , Ph. erawan  and Ph. sepaku  (and possibly in close relatives), the egg-sac is carried under the prosoma rather than in front of it ( Figs 3, 5–6View Figs 1 – 8, 16View Figs 9 – 16). For further details, see individual species descriptions below.

Three of the four species assigned tentatively to the halabala  group based on preliminary molecular data were observed in the field ( Ph. kuhapimuk  sp. nov.; Ph. khaolek  sp. nov.; and Ph. sudhami  ), and these were mostly found on rocks at cave entrances, with the body flat on the rock surface. Only Ph. sudhami  at Erawan  was mostly found on exposed tree roots at the riverside. Webs were either barely visible (a few threads close to the rock surface) or consisted of very delicate small domed sheets attached to the rock ( Ph. khaolek  sp. nov.). Silk tufts were not seen in any of these webs. Egg-sacs were carried in front of the body as in typical pholcids ( Fig. 51View Figs 49 – 56).

Distribution

The Ph. halabala  group is restricted to Southeast Asia, from Myanmar and southern China to Sumatra and Borneo ( Figs 17View Fig. 17, 57View Fig. 57).

RMNH

Netherlands, Leiden, Nationaal Natuurhistorische Museum ("Naturalis") [formerly Rijksmuseum van Natuurlijke Historie]

AME

USA, Florida, Gainesville, University of Florida, Florida Museum of Natural History, Allyn Museum

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Araneae

Family

Pholcidae

Genus

Pholcus