Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.


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).]


(Zoology) any vertebrate animal, such as a reptile, bird, or mammal, that possesses an amnion, chorion, and allantois during embryonic development. Compare anamniote
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)
References in periodicals archive ?
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).
Several researchers have long considered the possibility that the superficially reptile-like features of this animal might tell us something about amniote ancestry.
Taxonomic congruence versus total evidence, and amniote phylogeny inferred from fossils, molecules, and morphology.
1988: Amniote phylogeny and the importance of fossils.
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.
After the recent discovery of mesosaur embryos, we can state with a high degree of confidence that embryo retention developed early in amniote evolution, given that mesosaurs are among the basal-most reptiles and that they date from the Early Permian around 280 million years ago," she asserted.
2007): Impedance-matching hearing in Paleozoic reptiles: evidence of advanced sensory perception at an early stage of amniote evolution.