Do Vertebrates Have Protonephridia?

Overall, such systems, generally termed kidneys in vertebrates and nephridia or protonephridia in different invertebrate groups, are made up of tubular structures that employ osmoregulation to change the concentration of the solution (water, nitrogenous waste, and other solutes) that will be excreted from the body.

What animals contain Protonephridia?

Protonephridia are generally found in basal organisms such as flatworms. Protonephridia likely first arose as a way to cope with a hypotonic environment by removing excess water from the organism (osmoregulation). Their use as excretory and ionoregulatory structures likely arose secondarily.

Do molluscs have Protonephridia?

During the course of development, molluscs typically exhibit both types of excretory systems, protonephridia and a metanephridial system (Figure1 of[14]).