Animal mesoderm forms by enterocoelic pouching, through invagination of the endoderm. The main deuterostome phyla are the Echinodermata and the Chordata. Echinoderms are exclusively marine and include starfish, sea urchins, and sea cucumbers. The chordates are dominated by the vertebrates (animals with backbones), which consist of fishes, amphibians, reptiles, birds, and mammals. The deuterostomes also include the Hemichordata (acorn worms). The Ecdysozoa are protostomes, named after their shared trait of ecdysis, growth by moulting. They include the largest animal phylum, the Arthropoda, which contains insects, spiders, crabs, and their kin. All of these have a body divided into repeating segments, typically
Bacterial phyla Group A. Two species of the candidate phylum OP10, which is now called Armatimonadetes, where recently cultured: "Armatimonas rosea" isolated from the rhizoplane of a reed in a lake in Japan and "Chthonomonas calidirosea" from an isolate from geothermally heated soil at Hell's Gate, Tikitere, New Zealand. One species, "Caldisericum exile", of the candidate phylum OP5 was cultured, leading to it being named Caldiserica. The candidate phylum VadinBE97 is now known as Lentisphaerae after "Lentisphaera araneosa" and "Victivallis vadensis" were cultured. More recently several candidate phyla have been given provisional names despite the fact that they have no cultured representatives: