Variation in cuticular scales of the lynx spiders of the genus Hamataliwa and other genera (Araneae, Oxyopidae)

Abstract

This study presents the first complete description of the external and internal morphology of cuticular scales of spiders of the genus Hamataliwa and is also the first examination of intrageneric variation in the morphology of the scales of the lynx spiders (Oxyopidae). The cuticular scales of nine species, including taxa from Australia and Central and North America, were examined using scanning electron microscopy, paraffin carving, and transmission electron microscopy (whole mounts only). The surface morphology and internal anatomy of the scales exhibit considerable intra- and inter-specific variation. The structures that exhibit the most variation are (i) the plicae, small lateral ridges on the dorsal surface, which show variation in both morphology and pattern, and (ii) the rod-shaped, branched cuticular elements that occur within the lumina, which vary most dramatically in pattern. Scale morphology also varies regionally (i.e., with respect to location on the body) in most species. A comparison of the morphology of scales of Hamataliwa spp. with those of the striped lynx spider, Oxyopes salticus, and the green lynx spider, Peucetia viridans, suggests that scales may represent a useful phylogenetic character for understanding relationships both within and between genera in the Oxyopidae.