amniote

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amniote

[′am·nē‚ōt]

(zoology)

An animal that develops an amnion during its embryonic stage; includes birds, reptiles, and mammals.

References in periodicals archive ?

Any features shared by all three embryos probably came from distant common ancestors of all amniotes, the researchers note.

Essentially, "turtles have the same body plan as other amniotes.

A turtle's shell isn't so terribly bizarre after all: a critical fold may separate the reptile from its brethren

To solve the puzzle of amniote evolution, Carroll took some clues from the family of small, lungless salamanders known as plethodontids.

Along with its surprises, the tetrapod from Cheese Bay also offers some confirmation for a 30-year-old theory about how amniotes arose.

In 1970, Carroll proposed that amniotes evolved from a line of miniature amphibians, much smaller than brutes like Acanthostega.

These modern amphibians that can lay eggs on land and have direct development suggested a model for a transitional animal between the aquatically reproducing amphibians and the terrestrially reproducing early amniotes," says Carroll.

Out of the Swamps

The fact that nearly all living mammals have eye shapes that appear 'nocturnal' by comparison with other amniotes [mammals, reptiles and birds] is a testament to the strong influence that evolutionary history can have on modern anatomy," said Chris Kirk, associate professor of anthropology at The University of Texas at Austin.

Most mammals still retain prehistoric nocturnal life in their eyes

We can conclude, therefore, that the subsequent diversification of Palaeozoic amniotes and the rise of small and large omnivorous, herbivorous and predatory forms arose from these modest beginnings," they added.

Scientists find 280-million-year-old reptiles' preserved last meal

For example, humans are included in the following nested clades (using the informal names): eukaryotes, animals, deuterostomes, vertebrates, gnathostomes, tetrapods, amniotes, mammals, eutherians, primates, monkeys, apes, and great apes (see Dawkins, 2004 for more information on the ancestry of humans).

Phylogenies & tree-thinking

Today's birds have the smallest genomes among amniotes, the animal group that includes mammals, reptiles, and birds.

Birds' ancestors had small genomes too

Further study of the specimen may help clarify the evolutionary relationship between amniotes and nonamniotes, he says.