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deuterostome

[doo-ter-uh-stohm, dyoo-]
noun
  1. Embryology. a mouth that develops separately from the blastopore.
  2. Taxonomy. any member of the phyla (Chordata, Hemichordata, Echinodermata, Chaetognatha) in which the anus appears first, developing at or near the blastopore, cleavage is radial and indeterminate, and the mesoderm and coelom form from outgrowths of the primitive gut.
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Compare protostome.

Origin of deuterostome

First recorded in 1945–50; deutero- + -stome
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

deuterostome in Science

deuterostome

[dōōtə-rō-stōm′]
  1. Any of a major group of animals defined by its embryonic development, in which the first opening in the embryo becomes the anus. At this stage in their development, the later specialized function of any given embryonic cell has not yet been determined. Deuterostomes are one of the two groups of animals that have true body cavities (coeloms), and are believed to share a common ancestor. They include the echinoderms, chaetognaths, hemichordates, and chordates. Compare protostome.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.