List of transitional fossils

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This is a very tentative list of transitional fossils (fossil remains of a creature that exhibits primitive traits in comparison with more derived life-forms to which it is related). An ideal list would only recursively include 'true' transitionals, i.e. those forms morphologically similar to the ancestors of the monophyletic group containing the derived relative, and not intermediate forms. See the article on transitional fossils for an explanation of the difference with intermediate forms. Since all species are in transition due to natural selection, the very term "transitional fossil" is essentially a misconception. But the fossils listed represent significant steps in the evolution of major features in various vertebrate lines, and therefore fit the common usage of the phrase.

Contents

[edit] Nautiloids to Ammonoids

The Nautiloids → Ammonoids Evolutionary Series
Appearance Taxa Relationships Status Description Image
>500 Ma

Subclass:
390 Ma

Order:
  • Member of the Nautiloids.
  • Direct ancestor of the ammonoids.
370 Ma

Subclass:
  • Direct descendants of Bactirida.

[edit] Invertebrates to Fish

This list is incomplete; you can help by expanding it.
The Invertebrates → Fish Evolutionary Series
Appearance Taxa Relationships Status Description Image
 ??? Ma

Genus:

Lancet like in appearance. Oldest known ancestor of modern vertebrates

Vertebrate characters
 ??? Ma

Class:

 Had fin rays, chevron-shaped muscles and a notochord.
 ??? Ma

Genus:
 ??? Ma

Genus:
 ??? Ma

Genus:

[edit] Fish to Tetrapods

The Fish → Tetrapods Evolutionary Series
Appearance Taxa Relationships Status Description Image
 ??? Ma

Genus:
385 Ma

Genus:
380 Ma

Genus:
375 Ma

Genus:
368 Ma

Genus:
368 Ma

Genus:
365 Ma

Genus:
365 Ma

Genus:
360 Ma

Genus:
 ??? Ma

Genus:
 ??? Ma

Genus:
295 Ma

Genus:

[edit] Amphibians to Amniotes (early reptiles)

The Tetrapods → Reptiles Evolutionary Series
Appearance Taxa Relationships Status Description Image
 ??? Ma

Genus:
 ??? Ma

Genus:
 ??? Ma

Genus:
 ??? Ma

Genus:
315 Ma

Genus:
 ??? Ma

Genus:

[edit] Synapsid ("mammal-like reptiles") to mammals

The Synapsids → Mammals Evolutionary Series
Appearance Taxa Relationships Status Description Image
 ??? Ma

Genus:
 ??? Ma

Genus:
265 Ma

Genus:
 ??? Ma

Genus:
248-245 Ma

Genus:
205 Ma

Genus:
125 Ma

Genus:

[edit] Dinosaurs to birds

The Dinosaurs → birds Evolutionary Series
Appearance Taxa Relationships Status Description Image
125 Ma

Genus:
140-168 Ma

Genus:
155–150 Ma

Genus:
120 Ma

Genus:
93.5-75 Ma

Genus:

[edit] Evolution of whales

The whale Evolutionary Series
Appearance Taxa Relationships Status Description Image
55.8 ± 0.2 - 33.9 ± 0.1 Ma

Genus:
50 Ma

Genus:
46 Ma

Genus:
47 Ma

Genus:
41-33 Ma

Genus:
25 Ma

Genus:
40-34 Ma

Genus:
8-15 Ma

Genus:
26 Ma

Genus:

[edit] Evolution of the horse

The Hyracotherium → Equus Evolutionary Series
Appearance Taxa Relationships Status Description Image
60-45 Ma

Genus:
40-30 Ma

Genus:
20 Ma

Genus:
17-11 Ma

Genus:
12 Ma

Genus:
54-0 Ma

Genus:

[edit] Human evolution

Further information: Timeline of human evolution
The Human Evolutionary Series
Appearance Taxa Relationships Status Description Image
47 Ma Darwinius masillae transitional form between adapids and either prosimians or simians
13 Ma

Species:
4.4 Ma

Genus:
3.7 Ma

Genus:
1.9 Ma

Species:
1.6 Ma

Species:
2.0 Ma

Species:

[edit] See also

[edit] External links

Retrieved from "http://en.wikipedia.org/wiki/List_of_transitional_fossils"
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