The deuterostome mouth develops at the opposite end of the embryo from the blastopore and a digestive tract develops in the middle, connecting the two. For instance, humans have already formed a gut tube at the time of formation of the mouth and anus.

Subsequently, question is, are flatworms Deuterostomes? Acoelomorph flatworms are deuterostomes related to Xenoturbella. The most likely phylogeny links Xenoturbella and Acoelomorpha in a clade we call Xenacoelomorpha. The Xenacoelomorpha is the sister group of the Ambulacraria (hemichordates and echinoderms).

Also asked, which animal is a Deuterostome?

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

Are echinodermata Protostome or Deuterostome?

Most of the deuterostomes belong to one of two groups that include the majority of its members -- the echinoderms (the spiny skinned starfish, sea urchins, and their relatives) and the chordates (which include fish and other vertebrates).