Deuterostomia (/ˌdjuːtərəˈstoʊmi.ə/; lit. ´second mouth' in Greek) are animals typically characterized by their anus forming before their mouth during embryonic development. The group´s sister clade is Protostomia, ...
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animals whose digestive tract development is more varied. Some examples of deuterostomes include vertebrates (and thus humans), sea stars, and crinoids.
In deuterostomy, the developing embryo´s first opening (the blastopore) becomes the anus, while the mouth is formed at a different site later on. This was initially the group´s distinguishing characteristic, but deuterostomy has since been discovered among protostomes as well. This group is also known as enterocoelomates, because their coelom develops through enterocoely.
