The Pholcus halabala group: bringing order into taxonomic chaos
(published in Eur. J. Taxonomy http://dx.doi.org/10.5852/ejt.2016.190)
 
With currently over 300 described species, the genus Pholcus is by far the most species-rich genus in Pholcidae. For more than 200 years, almost any large pholcid with eight eyes and cylindrical abdomen somehow resembling the widespread Pholus phalangioides was assigned to this genus. The result was total chaos.

Some years ago I made a first attempt at revising the genus (Huber 2011). The main focus of that revision was a first tentative division of this humongous genus into more manageable units, which were explicitly proposed as “operational species groups”. Some of these were clearly non-monophyletic, i.e. unnatural and problematic.


All these species were previously part of the Pholcus halabala group. They are now representatives of four species groups, each of them very probably monophyletic. Photos: B. A. Huber

One of the most problematic species groups in my 2011 revision was the Southeast Asian Pholcus halabala group. A core group of three species was supported by fairly convincing synapomorphies, but eight further species were tentatively assigned to the group for lack of a better solution. The present paper is a first step towards resolving relationships among these species.

The result is that the halabala group is now split into four species groups, all of them probably monophyletic. In some of the representatives males have curiously modified 'head' regions, with brushes of hairs, spines, or very long eye stalks (below).

Male head regions of some Pholcidae species previously assigned to the Pholcus halabala group. Photos: B. A. Huber