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What is the formal name for animals with full digestive tracts, by which I mean a mouth and an anus, and what is the classification for animals that have a single hole for exchanging food and waste?

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Animals with a single hole do not form a monophyletic group: metazoa > eumetazoa >bilateria almost all have separate mouth and anus (except notably flatworms which is one reason it does not form a monophyletic group).

As species are not grouped in monophyletic groups by what they don't have (eg. invertebrates do not form a monophyletic group while vertebrates do) there is no particular group. Eumetazoa before the bilateria have a single mouth-anus.

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  • $\begingroup$ Some echinoderms also have one gut opening- i think brittle star $\endgroup$
    – WYSIWYG
    Sep 5, 2014 at 9:28

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