Amniote

Part of speech: noun

Pronunciation: /ˈam.nɪ.əʊt/

Definitions

1. An animal classified as a vertebrate that includes species like reptiles, birds, and mammals, marked by the presence of an amniotic egg for embryo development
2. A type of vertebrate characterized by a reproductive system that enables the creation of an amniotic egg, facilitating life in terrestrial environments
3. A group of vertebrates distinguished by their ability to produce an amniotic egg, which supports embryonic development in land-dwelling habitats

Etymology: Amniote takes its name from the amnion, the thin membrane that wraps the embryo in a fluid-filled sac, which is what allowed these animals to leave water behind. The word itself is a modern scientific coinage built from "Amniota," a Latinised label for the group, formed from the Greek "amnion" (lamb's caul or membrane) with the suffix "-ote" added. The Greek "amnion" was originally a term for the membrane around a lamb, from the ancient practice of using such membranes in ritual, so the name traces back to a sacrificial context rather than anything reptilian. The group is defined by that one structure. Reptiles, birds and mammals all share it, and so the category gathers together animals that otherwise look quite different: lizards, crocodiles, sparrows, and humans. The amnion protects a developing embryo from drying out, so these vertebrates could reproduce on land rather than returning to ponds or streams to spawn, as amphibians must.

Synonyms: amniotic vertebrate