High species diversity, male-female coevolution, and metaphyly in Southeast Asian pholcid spiders: the case of Belisana Thorell, 1898 (Araneae, Pholcidae)

Bernhard A. Huber

Abstract

The species-rich Southeast Asian spider genus Belisana Thorell, 1898 is revised. Previously, the genus contained only two species. Nine species are transferred from Spermophora, and 53 species are newly described. Diagnostic features are small size, six eyes and the lack of characters distinctive for other genera. Thus the genus is presently based on plesiomorphies, and cladistic analysis consistently fails to resolve Belisana as a monophylum. Belisana is thus explicitly treated as a metaphyletic group and not as a clade. Alternative taxonomic options within the frame of the current International Code of Zoological Nomenclature are discussed but rejected for lack of data, justification, and/or practicability. Geographically, Belisana ranges from India to the Pacific Islands, and from Korea to Australia. A tight correlation between the male chelicerae (distance between frontal apophyses) and the female external genitalia (distance between a pair of pockets) is documented in Belisana.