Systematics of the Damon variegatus group of African whip spiders (Chelicerata: Amblypygi): Evidence from behaviour, morphology and DNA.
Organisms, Diversity & Evolution 5 (2005): 203–236.
The African whip spider, Damon variegatus, exhibits a broad, discontinuous distribution from the Congo, through western Tanzania and Zimbabwe, to South Africa and Namibia. Variation in size, number of antenniform leg segments, and colouration, taken together with a discontinuous distribution, suggest that allopatric populations of D. variegatus may be reproductively isolated, and more than one species may be involved. Furthermore, many morphological characters of D. variegatus appear to be plesiomorphic if compared to closely related species, suggesting that D. variegatus might be paraphyletic, regardless of whether it is a single panmictic species or a group of partly or entirely reproductively isolated populations. This contribution attempts to determine whether D. variegatus is monophyletic and comprises more than one species, by investigating three sources of evidence: behaviour, morphology and DNA. Mating behaviour is observed and mate-recognition trials conducted between males and females from several populations of D. variegatus and related species of Damon. The morphology of spermatophores obtained during these matings is studied and a matrix of somatic and genitalic characters produced. These morphological data are analysed separately and in combination with DNA sequences from loci of three genes in the nuclear genome (18S rDNA, 28S rDNA and Histone H3) and three genes in the mitochondrial genome (12S rDNA, 16S rDNA and Cytochrome Oxidase I). Neither the comparative behavioural evidence gathered nor the spermatophore morphology conclusively suggest that D. variegatus comprises more than one species. However, the molecular data, analysed separately and in combination with the morphological data, reveal that D. variegatus is monophyletic and that the population of D. variegatus to the west of the Kalahari sand system (Namibia and southern Angola) is specifically distinct from those to the east. This new species is described as Damon sylviae, the diagnosis of D. variegatus s. str. is revised, and a key to the species of the D. variegatus group is provided.