Neodiapsida
Encyclopedia
Neodiapsida is a clade
or major branch of the reptilian family tree, that includes all Diapsid
s apart from some early primitive types known as Araeoscelidia
.
In phylogenetic systematics they are variously defined as the common ancestor and all its descendants of Younginiforms
and "crown diapsids" (the common ancestor of lizard
s, crocodilia
ns and birds, and all their descendants) [Callaway 1997], or all diapsids that are more closely related to Sauria
than to Araeoscelidia
(Laurin and Gauthier 2000).
Early or basal Permian
neodiaspids were lizard-like, but already include specialised swimming Claudiosaurus
and gliding Coelurosauravidae
forms, as well as more conventional lizard-like forms (Youngina
etc.). Before the end of the Permian, the neodiaspids give rise to the main branches of the diapsid evolutionary tree, the lepidosaurs
and archosaurs
.
The clade is defined by a number of details in skull and skeleton, for which see Laurin and Gauthier 2000.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
or major branch of the reptilian family tree, that includes all Diapsid
Diapsid
Diapsids are a group of reptiles that developed two holes in each side of their skulls, about 300 million years ago during the late Carboniferous period. Living diapsids are extremely diverse, and include all crocodiles, lizards, snakes, and tuatara...
s apart from some early primitive types known as Araeoscelidia
Araeoscelidia
Araeoscelidia or Araeoscelida is a clade of extinct diapsid reptiles superficially resembling lizards, extending from the Late Carboniferous to the Early Permian....
.
In phylogenetic systematics they are variously defined as the common ancestor and all its descendants of Younginiforms
Younginiformes
Younginiformes is a replacement name for the taxon Eosuchia, proposed by Alfred Romer in 1947.The Eosuchia having become rather a dustbin for many probably distantly-related primitive diapsid reptiles ranging from the late Carboniferous to the Eocene, Romer proposed that this be replaced by...
and "crown diapsids" (the common ancestor of lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s, crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
ns and birds, and all their descendants) [Callaway 1997], or all diapsids that are more closely related to Sauria
Sauria
Sauria is a clade of reptiles that includes all living diapsids, as well as their common ancestor and all its extinct descendants. The ancestral saurian was probably a small lizard-like creature living in the Permian Period...
than to Araeoscelidia
Araeoscelidia
Araeoscelidia or Araeoscelida is a clade of extinct diapsid reptiles superficially resembling lizards, extending from the Late Carboniferous to the Early Permian....
(Laurin and Gauthier 2000).
Early or basal Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
neodiaspids were lizard-like, but already include specialised swimming Claudiosaurus
Claudiosaurus
Claudiosaurus is an extinct genus of diapsid reptile from the Permian period of Madagascar.Claudiosaurus was one of the first members of the Neodiapsida, a group of reptiles containing most diapsids except the primitive Araeoscelidia. It had a relatively long body and neck, reaching on overall...
and gliding Coelurosauravidae
Coelurosauravidae
Coelurosauravidae was a family of avicephalans from the Permian and Triassic time periods. They lived in trees, and were typically two feet long...
forms, as well as more conventional lizard-like forms (Youngina
Youngina
Youngina is an extinct genus of diapsid reptile from the Late Permian Beaufort Group of the Karoo Red Beds of South Africa. This, and a few related forms, make up the family Younginidae, within the Order Eosuchia...
etc.). Before the end of the Permian, the neodiaspids give rise to the main branches of the diapsid evolutionary tree, the lepidosaurs
Lepidosauromorpha
Lepidosauromorpha is a group of reptiles comprising all diapsids closer to lizards than to archosaurs . The only living sub-group is the Lepidosauria: extant lizards, snakes, and tuatara...
and archosaurs
Archosauromorpha
Archosauromorpha is an infraclass of diapsid reptiles that first appeared during the late Permian and became more common during the Triassic. Included in this infraclass are the groups Rhynchosauria, Trilophosauridae, Prolacertiformes, Archosauriformes, and, tentatively, Choristodera...
.
The clade is defined by a number of details in skull and skeleton, for which see Laurin and Gauthier 2000.
External links
- Eureptilia: Neodiapsida
- Neodiapsida cladogram