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Plesiadapis is one of the oldest known primate-like mammal genera which existed about 58–55 million years ago in North America and Europe. [2] [3] Plesiadapis means "near-Adapis", which is a reference to the adapiform primate of the Eocene period, Adapis.
Figure 1:In mammals, the quadrate and articular bones are small and part of the middle ear; the lower jaw consists only of dentary bone.. While living mammal species can be identified by the presence of milk-producing mammary glands in the females, other features are required when classifying fossils, because mammary glands and other soft-tissue features are not visible in fossils.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
First balanids and eucalypts, extinction of embrithopod and brontothere mammals, earliest pigs and cats. 28 Ma Paraceratherium appears in the fossil record, the largest terrestrial mammal that ever lived. First pelicans. 25 Ma Pelagornis sandersi appears in the fossil record, the largest flying bird that ever lived. 25 Ma First deer. 24 Ma ...
Phylogenetic tree of the primates Notharctus. The evolutionary history of the primates can be traced back 57-90 million years. [1] One of the oldest known primate-like mammal species, Plesiadapis, came from North America; [2] another, Archicebus, came from China. [3]
An early, inefficient version of diaphragm may have evolved in synapsids. The earliest synapsids, or "proto-mammals," are the pelycosaurs. The pelycosaurs were the first animals to have temporal fenestrae. Pelycosaurs were not therapsids but their ancestors. The therapsids were, in turn, the ancestors of mammals.
Earth is the only place in the universe known to harbor life, where it exists in multiple environments. [8] [9] The origin of life on Earth was at least 3.5 billion years ago, possibly as early as 3.8-4.1 billion years ago. [2] [3] [4] Since its emergence, life has persisted in several geological environments.
The earliest known animals are cnidarians from about , but these are so modern-looking that they must be descendants of earlier animals. [92] Early fossils of animals are rare because they had not developed mineralised , easily fossilized hard parts until about 548 million years ago . [ 93 ]