Arthropod limbs and their development

Abstract

Arthropods are characterized by bodies that are segmented and by the possession of paired ventral limbs carried on all, most or some of these body segments. These paired limbs are primitively segmented-and the name of the taxon Arthropoda refers to the jointed limbs of its members. While the origin of arthropods is not the focus of this chapter, it is relevant to note that the recent discovery of a Cambrian lobopodian, Diania cactiformis, possessing robust and probably sclerotized appendages with what Liu et al. (2011) interpret as articulating elements, led them to speculate whether arthropodization (sclerotization of limbs) preceded arthrodization (sclerotization of the body). In such a scenario, the acquisition of jointed limbs assumes centre stage as the key driver of arthropod evolution.