Ambulacraria

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Ambulacrarians Temporal range: Late Ediacaran - Recent
Various sea stars 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)

Ambulacraria is a clade of invertebrates which includes echinoderms, hemichordates, and Xenoturbellida; a member of this group is called an ambulacrarian. This superphylum is largely identical to the superphylum Deuterostomia, except the phylum Chordata is not found in Ambulacraria.

The three living phyla, with representative organisms, are:

• Phylum Echinodermata (sea stars, 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)

Fossil taxa that may lie on the stem lineage:

•  ?Superphylum Ambulacraria#
  • unranked clade Cambroernida
    • unranked clade = Eldoniida
    • † Herpetogaster Caron, Conway Morris & Shu, 2010^[1] - with one species: † Herpetogaster collinsi Caron, Conway Morris & Shu, 2010^[1]

References