Deuterostome

Deuterostomes are a nephrozoan superphylum of bilaterian animals, a taxon above the level of phylum. It is not part of the usual system of classification.

Deuterostomia Temporal range: late Ediacaran – Recent
A sea cucumber
Scientific classification
Kingdom:	Animalia
(unranked):	Nephrozoa
Superphylum:	Deuterostomia Grobben, 1908
Phyla and clades
Echinodermata (20,000 species) Hemichordata (71 species) Chordata (63,000+ species) Saccorhytida (one species of fossil) "Ambulacraria"

They are bilateral animals, and are contrasted with the protostomes. Deuterostomes are distingued by their embryo: in deuterostomes, the first opening (the blastopore) becomes the anus, while in protostomes it becomes the mouth.

Classification

These are the living phyla of deuterostomes:

• Chordata (vertebrates and their kin)
• Echinodermata (starfishes, sea urchins, sea cucumbers, etc.)
• Hemichordata (acorn worms and possibly graptolites)

This is an extinct deuterostome clade:

• Saccorhytida