Ambulacraria

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Ambulacrarians Fossil range: Late Ediacaran - Recent
Various starfish and sea urchins among mussel shells in the rocky intertidal zone of Kachemak Bay.
Scientific classification
Kingdom: Animalia Subkingdom: Eumetazoa (unranked): Bilateria Superphylum: Ambulacraria
Phyla
Xenoturbellida (2 species) Echinodermata (20,000 species) Hemichordata (71 species)

The Ambulacraria is a clade of invertebrates which includes echinoderms, hemichordates, and Xenoturbellida. This superphylum is largely identical to the superphylum Deuterostomia, except the phylum Chordata is not found in Ambulacraria.

There three living phyla, with representative organisms, are:

• Phylum Echinodermata (starfish, sea urchins, brittle stars, sea cucumbers, feather stars, sea lilies, etc.)
• Phylum Hemichordata (acorn worms, Pterobranchia, and possibly graptolites)
• Phylum Xenoturbellida (two species of worm-like animals)