Aquatic arthropods

Trilobites (; meaning "three-lobed entities") are extinct marine arthropods that form the class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolutionary biol

Dolomedes is a genus of large spiders of the family Dolomedidae. They are also known as fishing spiders, raft spiders, dock spiders or wharf spiders. Almost all Dolomedes species are semiaquatic, with the exception of the tree-dwelling D. albineus of the southeastern United States. Many species have a striking pale stripe down each side of the body.