Bilateria


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Bilateria

[‚bī·lə′tir·ē·ə]
(zoology)
A major division of the animal kingdom embracing all forms with bilateral symmetry.
References in periodicals archive ?
According to this divergence model, one or a few ancestral "eye genes," for example the regulatory gene Pax6, evolved in the ancestral bilateria, resulting in the first eyespot.
Consideration of RNA secondary structure significantly improves likelihood-based estimates of phylogeny: examples from the Bilateria.
On the other hand, Bilateria, which include worms, mollusks, insects, and vertebrates, did not descend directly from this "spongy" ancestor.