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e. Reptiles arose about 320 million years ago [1] during the Carboniferous period. Reptiles, in the traditional sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled eggs, and possess ectothermic metabolisms. So defined, the group is paraphyletic, excluding endothermic animals like birds that are ...
Slight increase in diversity of cold-tolerant ostracods and foraminifers, along with major extinctions of gastropods, reptiles, amphibians, and multituberculate mammals. Many modern mammal groups begin to appear: first glyptodonts, ground sloths, canids, peccaries, and the first eagles and hawks. Diversity in toothed and baleen whales. 33 Ma
e. The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian sub-period of the late Carboniferous period. By the mid- Triassic, there were many synapsid species that looked like mammals. The lineage leading to today's mammals split up in the Jurassic; synapsids from this ...
From amphibians came the first reptiles: Hylonomus is the earliest known reptile. It was 20 cm (8 in) long (including the tail) and probably would have looked rather similar to modern lizards. It had small sharp teeth and probably ate small millipedes and insects. It is a precursor of later amniotes (broadest sense of "reptile").
Synapsida[a] is one of the two major clades of vertebrate animals in the group Amniota, the other being the Sauropsida (which includes reptiles and birds). The synapsids were the dominant land animals in the late Paleozoic and early Mesozoic, but the only group that survived into the Cenozoic are mammals. [7]
The term amniote comes from the amnion, which derives from Greek ἀμνίον (amnion), which denoted the membrane that surrounds a fetus. The term originally described a bowl in which the blood of sacrificed animals was caught, and derived from ἀμνός (amnos), meaning "lamb". [17]
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
This is an accepted version of this page This is the latest accepted revision, reviewed on 8 November 2024. Group of animals including lepidosaurs, testudines, and archosaurs This article is about the animal class. For other uses, see Reptile (disambiguation). Reptiles Temporal range: Late Carboniferous–Present PreꞒ Ꞓ O S D C P T J K Pg N Tuatara Saltwater crocodile Common box turtle ...