Seiter M, Schwaha T, Prendini L, Gorb SN & Wolff JO (2022)
Journal of Morphology. Accepted Author Manuscript. doi.org/10.1002/jmor.21452. Link. Published online 22 January 2022

Abstract

Like other arthropods, whip spiders of the arachnid order Amblypygi Thorell, 1883 protect themselves against external environmental influences. In addition to the epicuticle, the outermost layer of the exoskeleton, an additional cement layer, i.e., the cerotegument, is deposited as superhydrophic globules over certain body parts in this taxon. Due to the high level of interspecific variation, the cerotegument structure and the morphology of its associated gland openings, have been suggested to be informative for whip spider systematics and taxonomy. The first comparative study of the cerotegument is presented herein, based on a survey across four families, 16 genera and 62 species of Euamblypygi Weygoldt, 1996, the suborder comprising all extant whip spiders except the rare monotypic family Paracharontidae Weygoldt, 1996. Results confirmed that the morphology of the colloidal particles and their assembly on globules differ considerably among taxa, but that the level of variation differs among lineages. Interspecific variation in cerotegument ultrastructure was highest among species of Neoamblypygi Weygoldt, 1996, making it an informative character in this clade. Evolutionary trends and interspecific variation in the structure of the amblypygid cerotegument are briefly discussed.