This article is about an extinct order of diapsid reptiles from the Permian and Triassic. For the clade of crocodylomorphs, see Eusuchia.
Eosuchia
Temporal range: Permian-Triassic 260–205.6 Ma
PreꞒ
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
Hovasaurus
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Class:
Reptilia
Clade:
Diapsida
Order:
†Eosuchia Broom, 1914
Eosuchians are an extinct order of diapsid reptiles. Depending on which taxa are included the order may have ranged from the late Carboniferous to the Eocene but the consensus is that eosuchians are confined to the Permian and Triassic[citation needed].
Eosuchia was initially defined to include all "thecodontian" reptiles which did not have an antorbital fenestra but did retain tabulars, postparietals and a large pineal foramen (Broom, 1914). Broom coined the term as a new suborder for Youngina.
A definition for inclusion in the order is difficult: it is almost easier to list the primitively-diapsid reptiles that have not been included at one time or another. The order has almost been treated as a dustbin for diapsids that are not obviously lepidosaurian or archosaurian. One consequence has been Romer's suggestion of the alternative order Younginiformes to be applied strictly to those forms with the primitive diapsid form, in particular, a complete lowermost arch as the quadratojugal and jugal bones of the skull meet.[1]
The one constant eosuchian has been Youngina, a small lizard-shaped reptile from the Upper Permian of South Africa. This and a couple of other genera make up the family Younginidae.
The tangasaurids, a family that includes forms apparently adapted for swimming in fresh water, is also usually included.[2]
In some phylogenies Eosuchia has been treated (probably erroneously) as a sister lepidosaur taxon to Squamata and Rhynchocephalia.[3]
^http://tolweb.org/articles/?article_id=465 For example and discussion
^"Neodiapsida". Archived from the original on 2006-08-31. Retrieved 2006-05-31. Phylogeny treating Eosuchia in its strict sense
^http://tolweb.org/Diapsida At one time or another all of the taxa in black in this phylogeny has been placed within "Eosuchia" in one sense or another
eosuchians are confined to the Permian and Triassic[citation needed]. Eosuchia was initially defined to include all "thecodontian" reptiles which did...
forms, make up the family Younginidae, within the order Eosuchia (proposed by Broom in 1914). Eosuchia, having become a wastebasket taxon for many probably...
placed Choristodera within the paraphyletic or polyphyletic grouping of "Eosuchia", describing them, as “an offshoot of the basic eosuchian stock”, a classification...
and mammals, respectively. Thus his Sauropsida included Procolophonia, Eosuchia, Millerosauria, Chelonia (turtles), Squamata (lizards and snakes), Rhynchocephalia...
plesiosaurs. Despite the controversy over the definition of the order Eosuchia (to which the Tangasauridae are considered to have belonged) and as to...
also be a member of the family. Younginidae was traditionally assigned to Eosuchia, an order containing an assemblage of basal diapsids now thought to represent...
Permian-Triassic of Africa and Madagascar. It has been used as a replacement for "Eosuchia". Younginiformes (including Acerosodontosaurus, Hovasaurus, Kenyasaurus...
1985). "Aspects of some anatomical structures of Champsosaurus (Reptilia: Eosuchia)". Journal of Vertebrate Paleontology. 5 (2): 111–127. Bibcode:1985JVPal...
affinity to intermingle together in classification schemes. Names such as "Eosuchia", "Euryapsida", "Younginiformes", "Protorosauria", and others were all...
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