Deuterostomes (from Greek: lit. 'second mouth') are bilaterian animals of the superphylum Deuterostomia (/ ˌdjuːtərəˈstoʊmi.ə /), [3][4] typically characterized by their anus forming before the mouth during embryonic development.

Deuterostomia, (Greek: “second mouth”), group of animals—including those of the phyla Echinodermata (e.g., starfish, sea urchins), Chordata (e.g., sea squirts, lancelets, and vertebrates), Chaetognatha (e.g., arrowworms), and Brachiopoda (e.g., lamp shells)—classified together on the basis of embryological development and by molecular ...

2017年4月28日 · The Deuterostomes are a clade of animals that undergo deuterostomy during their embryonic development. They are a sister-clade of the Protostomes, and the two together with the Xenacoelomorpha form the major group of animals called the Bilateria —a major group animals which display bilateral symmetry and are mostly triploblastic.

2024年5月21日 · Deuterostomes are a large superphylum of animals that includes chordates (vertebrates), echinoderms, hemichordates (acorn worms), and one small phyla, Xenoturbellida, which consists of two marine worm-like species.

Deuterostomes are a monophyletic group of animals that include the vertebrates, invertebrate chordates, ambulacrarians and xenoturbellids.

Deuterostomes are a superphylum within bilateria, containing those animals which generally form an anus before a mouth. It includes chordates (vertebrates, ascidians, and amphioxus) as well as echinoderms (sea urchins, sand dollars, and starfish) and hemichordates (acorn worms).

Recall that protostome and deuterostomes differ in certain aspects of their embryonic development, and they are named based on which opening of the digestive cavity develops first. The word deuterostome comes from the Greek word meaning “mouth second,” indicating that the anus is the first to develop.

In deuterostomes, the endodermal lining of the archenteron usually forms buds called coelomic pouches that expand and ultimately obliterate the embryonic blastocoel (the cavity within the blastula and early gastrula) to become the embryonic mesoderm, the third germ layer.

In deuterostomes, cell divisions of the zygote occur by radial cleavage, and cell fates are not precisely determined. Another characteristic feature is that the first opening to form in the blastula becomes the anus and the second opening becomes the mouth.

2017年2月26日 · Protostomes develops mouth from the blastopore during the development of embryo. On the other hand, deuterostomes develop anus from the blastopore. Both protostomia and deuterostomia also consist of differences in the development of their three germ layers. Deuterostomes bear a higher modified nervous and muscular systems.