List of transitional fossils

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This is an incomplete list, which may never be able to satisfy certain standards for completeness.

Revisions and sourced additions are welcome.

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 supposed to be 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.

1 Nautiloids to Ammonoids
2 Invertebrates to Fish
3 Fish to Tetrapods
4 Amphibians to Amniotes (early reptiles)
5 Synapsid (mammal-like "reptiles") to mammals
6 Dinosaurs to birds
7 Evolution of whales
8 Evolution of the horse
9 Non-human apes to modern humans
10 See also
11 External links

[edit] Nautiloids to Ammonoids

*The Nautiloids* → Ammonoids Evolutionary Series**
Appearance	Taxa	Relationships	Status	Description	Image
>500 Ma	Subclass: Nautiloidea
390 Ma	Order: Bactritida	Member of the Nautiloids. Direct ancestor of the ammonoids.
370 Ma	Subclass: Ammonoidea	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: Pikaia
??? Ma	Class: Conodont
??? Ma	Genus: Haikouichthys
??? Ma	Genus: Arandaspis
??? Ma	Genus: Birkenia

[edit] Fish to Tetrapods

*The Fish* → Tetrapods Evolutionary Series**
Appearance	Taxa	Relationships	Status	Description	Image
??? Ma	Genus: Osteolepis
385 Ma	Genus: Eusthenopteron
380 Ma	Genus: Panderichthys
375 Ma	Genus: Tiktaalik
368 Ma	Genus: Elginerpeton
368 Ma	Genus: Obruchevichthys
365 Ma	Genus: Acanthostega
365 Ma	Genus: Ichthyostega
360 Ma	Genus: Hynerpeton
??? Ma	Genus: Tulerpeton
??? Ma	Genus: Pederpes
295 Ma	Genus: Eryops

[edit] Amphibians to Amniotes (early reptiles)

*The Tetrapods* → Reptiles Evolutionary Series**
Appearance	Taxa	Relationships	Status	Description	Image
??? Ma	Genus: Proterogyrinus
??? Ma	Genus: Limnoscelis
??? Ma	Genus: Tseajaia
??? Ma	Genus: Solenodonsaurus
315 Ma	Genus: Hylonomus
??? Ma	Genus: Paleothyris

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

*The Synapsids* → Mammals Evolutionary Series**
Appearance	Taxa	Relationships	Status	Description	Image
??? Ma	Genus: Protoclepsydrops
??? Ma	Genus: Clepsydrops
265 Ma	Genus: Dimetrodon
??? Ma	Genus: Procynosuchus
248-245 Ma	Genus: Thrinaxodon
205 Ma	Genus: Morganucodon
125 Ma	Genus: Yanoconodon

[edit] Dinosaurs to birds

*The Dinosaurs* → birds Evolutionary Series**
Appearance	Taxa	Relationships	Status	Description	Image
125 Ma	Genus: Yixianosaurus
140-168 Ma	Genus: Pedopenna
155–150 Ma	Genus: Archaeopteryx
120 Ma	Genus: Confuciusornis
93.5-75 Ma	Genus: Ichthyornis

[edit] Evolution of whales

*The whale Evolutionary* Series**
Appearance	Taxa	Relationships	Status	Description	Image
	Genus: Pakicetus
	Genus: Ambulocetus
	Genus: Kutchicetus
	Genus: Artiocetus
	Genus: Aetiocetus
	Genus: Dorudon
	Genus: Basilosaurus
	Genus: Eurhinodelphis
	Genus: Mammalodon

[edit] Evolution of the horse

*The Hyracotherium* → Equus Evolutionary Series**
Appearance	Taxa	Relationships	Status	Description	Image
	Genus: Hyracotherium
	Genus: Mesohippus
	Genus: Parahippus
	Genus: Merychippus
	Genus: Pliohippus
	Genus: Equus

[edit] Non-human apes to modern humans

The Human Evolutionary Series
Appearance	Taxa	Relationships	Status	Description	Image
	Species: Pierolapithecus catalaunicus
	Genus: Ardipithecus
	Genus: Australopithecus
	Species: Homo rudolfensis
	Species: Homo habilis
	Species: Homo erectus