Archosaur

Archosaurs
Temporal range:
Early TriassicPresent, 250–0 Ma
Yellow-billed stork kazinga.jpg
Birds and crocodilians (in this case a yellow-billed stork and a Nile crocodile) are the only living archosaur groups.
Scientific classification edit
Kingdom:Animalia
Phylum:Chordata
Class:Reptilia
Clade:Eucrocopoda
Clade:Archosauria
Cope, 1869
Subgroups
Synonyms

Arctopoda Haeckel, 1895
Avesuchia Benton, 1999

Archosaurs are a group of diapsid amniotes whose living representatives consist of birds and crocodilians. This group also includes all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most recent common ancestor of living birds and crocodilians. It includes two main clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs).

Distinguishing characteristics

Archosaurs can be distinguished from other tetrapods on the basis of several synapomorphies, or shared characteristics, first found in a common ancestor. The simplest and most widely agreed synapomorphies of archosaurs include teeth set in sockets, antorbital and mandibular fenestrae (openings in front of the eyes and in the jaw, respectively),[1] and a fourth trochanter (a prominent ridge on the femur).[2] Being set in sockets, the teeth were less likely to be torn loose during feeding. This feature is responsible for the name "thecodont" (meaning "socket teeth"),[3] which paleontologists used to apply to many Triassic archosaurs.[2] Some archosaurs, such as birds, are secondarily toothless. Antorbital fenestrae reduced the weight of the skull, which was relatively large in early archosaurs, rather like that of modern crocodilians. Mandibular fenestrae may also have reduced the weight of the jaw in some forms. The fourth trochanter provides a large site for the attachment of muscles on the femur. Stronger muscles allowed for erect gaits in early archosaurs, and may also be connected with the ability of the archosaurs or their immediate ancestors to survive the catastrophic Permian-Triassic extinction event.[citation needed]

Other Languages
Afrikaans: Archosauria
العربية: أركوصورات
brezhoneg: Archosauria
català: Arcosaures
Cebuano: Archosauria
čeština: Archosauři
Deutsch: Archosauria
español: Archosauria
Esperanto: Arkosaŭroj
euskara: Archosauria
français: Archosauria
galego: Arcosauros
한국어: 지배파충류
italiano: Archosauria
ქართული: არქოზავრები
қазақша: Архозаврлар
Кыргызча: Архозавралар
Latina: Archosauria
lietuvių: Archozaurai
magyar: Archosauria
മലയാളം: ആർച്ചോസോർ
Nederlands: Archosauria
日本語: 主竜類
norsk: Arkosaurer
norsk nynorsk: Arkosaurar
occitan: Archosauria
ଓଡ଼ିଆ: ଆର୍କୋସର
oʻzbekcha/ўзбекча: Arxozavrlar
پنجابی: آرکوسار
polski: Archozaury
português: Archosauria
русский: Архозавры
Scots: Archosaur
sicilianu: Archosauria
Simple English: Archosaur
slovenčina: Prajaštery
српски / srpski: Archosauria
srpskohrvatski / српскохрватски: Archosauria
suomi: Arkosaurit
Tagalog: Arkosauro
українська: Архозаври
Tiếng Việt: Thằn lằn chúa
Winaray: Arkosauro
中文: 主龍類