Meeting Abstract
Onychophorans (velvet worms) are carnivorous, terrestrial invertebrates that occur in tropical and temperate forests of the southern hemisphere and around the equator. Together with tardigrades (water bears), onychophorans are regarded as the closest relatives of arthropods. One of the most peculiar features of onychophorans is their hunting and feeding behavior. The animals use a sticky slime secretion, which is ejected via a pair of slime papillae, to entangle their prey, such as soil-dwelling invertebrates. After the prey has been immobilized, its cuticle is punctured using a pair of jaws that are internalized appendages of the second head segment. The jaws are innervated by the deutocerebrum and, thus, homologous to the chelicerae of chelicerates, and the (first) antennae of myriapods, crustaceans and insects. They might be serial homologs of the paired claws associated with each walking limb of the trunk. The structure of the jaws is similar in representatives of the two major onychophoran subgroups, the Peripatidae and Peripatopsidae. Each jaw is characterized by an outer and an inner blade; while the outer blade consists only of a large principal tooth and up to three accessory teeth, the inner blade bears numerous additional denticles that are separated by a diastemal membrane in peripatids. The onychophoran jaws are associated with large apodemes and specialized muscles that enable their movement. In this talk, I review our current knowledge on the onychophoran jaws and provide some new insights into their composition.
