Sphenosuchians Fossil range: Late Triassic - Late Jurassic
Scientific classification
Infraclass:	Archosauromorpha
Superorder:	Crocodylomorpha
Suborder:	Sphenosuchia
Families:	Sphenosuchidae

Sphenosuchia is the name of a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture.

Contents 1 Stratigraphic Range 2 Phylogeny 2.1 List of sphenosuchian genera 3 References

Stratigraphic RangeEdit

The earliest known members of the group occur (i.e. Hesperosuchus) in the Lower Petrified Forest member of the Chinle Formation, these specimens are Carnian in age. Only one sphenosuchian is currently known from the Middle Jurassic, Junggarsuchus, from the Junggar Basin (Shishugou Formation) of China during either the Bathonian or the Callovian (~165 MA) in age.^[1] The youngest sphenosuchian, Macelognathus, is known from the Late Jurassic of North America during the Kimmeridgian, (155 - 150 Ma).

PhylogenyEdit

The monophyly of the group is debated, although several synapomorphies characterize the clade, including extremely slender limbs, a compact carpus and an elongate coracoid process.

In 2002, Clark and Sues argued that the Spenosuchia formed a clade.^[2] More recently, however, Clark et al. (2004) argued for the paraphyly of the group, contending that morphological characters were secondarily lost in more highly derived crocodylomorphs.^[1] Further analysis and study is required before the group's monophyly is resolved with certainty — a perfect phylogenetic analysis is, at present, impossible due to a paucity of fossil remains demonstrating phylogenetically informative characters.

List of sphenosuchian generaEdit

Because of the current uncertainty surrounding sphenosuchian monophyly, no phylogenetic tree is presented in the article; however, the genera currently classified as sphenosuchians are:

• Barbarenasuchus
• Dyoplax
• Parrishia
• Trialestes

Genus	Status	Age	Location	Description
†Dibothrosuchus	Valid	Early Jurassic	Asia
†Dromicosuchus	Valid	Late Triassic	North America
†Hallopus	Valid	Late Jurassic	North America	Possible synonym of Macelognathus
†Hesperosuchus	Valid	Late Triassic	North America
†Junggarsuchus	Valid	Middle Jurassic	Asia
†Kayentasuchus	Valid	Early Jurassic	North America
†Litargosuchus	Valid	Early Jurassic	Africa
†Macelognathus	Valid	Late Jurassic	North America
†Pedeticosaurus	Valid
†Phyllodontosuchus	Valid	Early Jurassic	Asia
†Pseudohesperosuchus	Valid
†Redondavenator	Valid	Late Triassic	North America
†Saltoposuchus	Valid	Late Triassic	Europe and North America
†Sphenosuchus	Valid	Early Jurassic	Africa
†Terrestrisuchus	Valid	Late Triassic	Europe

ReferencesEdit