Eusuchia ("true crocodiles") is a
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
of
crocodylomorphThe Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...
s that first appears in the
Early CretaceousThe Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
with
HylaeochampsaHylaeochampsa is an extinct genus of crocodylomorph that may have been an eusuchian. It is known only from a partial skull recovered from Barremian-age rocks of the Lower Cretaceous Vectis Formation of the Isle of Wight...
. All living crocodilian
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
are eusuchians, as are many extinct forms.
Unlike primitive crocodylomorphs, crocodyliforms have a secondary bony palate. This feature enables living crocodylians to safely breathe in through their nostrils while the rest of the head (including the mouth) remains submerged.
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Eusuchia ("true crocodiles") is a
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
of
crocodylomorphThe Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...
s that first appears in the
Early CretaceousThe Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
with
HylaeochampsaHylaeochampsa is an extinct genus of crocodylomorph that may have been an eusuchian. It is known only from a partial skull recovered from Barremian-age rocks of the Lower Cretaceous Vectis Formation of the Isle of Wight...
. All living crocodilian
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
are eusuchians, as are many extinct forms.
Description
Unlike primitive crocodylomorphs, crocodyliforms have a secondary bony palate. This feature enables living crocodylians to safely breathe in through their nostrils while the rest of the head (including the mouth) remains submerged. This structure reaches its greatest elaboration among eusuchians, in whom the internal nares are completely surrounded by the pterygoid bones.