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Any of numerous vertebrates of the group Amniota, characteristically having an amnion during embryonic development and including the reptiles, birds, and mammals.

[From New Latin amniōta, amniotes, from Greek amniōn, amnion (influenced by amniotic).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Zoology) any vertebrate animal, such as a reptile, bird, or mammal, that possesses an amnion, chorion, and allantois during embryonic development. Compare anamniote
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.amniote - any member of the Amniotaamniote - any member of the Amniota    
craniate, vertebrate - animals having a bony or cartilaginous skeleton with a segmented spinal column and a large brain enclosed in a skull or cranium
Amniota - higher vertebrates (reptiles, birds and mammals) possessing an amnion during development
amnion, amnios, amniotic sac - thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
chorion - the outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals)
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Researchers believe the creature is a "stem amniote" -- an early land-dwelling animal that later evolved into modern mammals, birds and reptiles.
Rearranging gastrulation in the name of yolk: evolution of gastrulation in yolk-rich amniote eggs.
The evolution of viviparity in amniote vertebrates: egg retention versus egg size reduction.
The AT skew and GC skew values of mitochondrial genome sequences for Coraciiformes were consistent with the rule that the AT skew was positive while the GC skew was negative in amniote mtDNA (Quinn and Wilson, 1993).
Plikus et al., "Evo-Devo of amniote integuments and appendages," International Journal of Developmental Biology, vol.
Hylonomus lyelli, meaning "forest dweller", named in honour of his mentor and friend, Sir Charles, a century and a half later was proclaimed Nova Scotia's Provincial fossil and remains the earliest known amniote in the fossil record (Carroll 1964, 1970; Reisz 1997; Clack 2002).
Protein sequences indicate that turtles branched off from the amniote tree after mammals.
It is probable that this better means of expelling carbon dioxide allowed these creatures to become fully independent from the water and contributed to the development of the amniote egg, which was integral to the transition from amphibian to reptile.
Because of this, we investigated the generality of our conclusions with mitochondrial and nuclear genes from a widely accepted four-taxon amniote phylogeny.