Sphenosuchia is a suborder of basal

Basal (phylogenetics)

In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 crocodylomorphs that first appeared in the Triassic

Triassic

The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 and occurred into the Late Jurassic

Late Jurassic

The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...

. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, which include all living crocodilians.

Stratigraphic range

The earliest known members of the group (i.e. Hesperosuchus

Hesperosuchus

Hesperosuchus is an extinct genus of crocodylomorph reptile that contains a single species, Hesperosuchus agilis. Remains of this sphenosuchian have been found in Late Triassic strata from Arizona and New Mexico....

) are early Norian

Norian

The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...

 in age, found in the Blue Mesa Member of the Chinle Formation

Chinle Formation

The Chinle is a geologic formation that is spread across the U.S. states of northern Arizona, Nevada, Utah, western New Mexico, and western Colorado. The Chinle is controversially considered to be synonymous to the Dockum Group in eastern Colorado, eastern New Mexico, southwestern Kansas, the...

. Only one sphenosuchian is currently known from the Middle Jurassic, Junggarsuchus

Junggarsuchus

Junggarsuchus is an extinct genus of sphenosuchian crocodylomorph from the Middle Jurassic of China. The type species is J. sloani.-Anatomy:...

, from the Junggar Basin (Shishugou Formation

Shishugou Formation

The Shishugou Formation is a geological formation in Xinjiang, China, whose strata date back to the Late Jurassic period. Dinosaur remains are among the fossils that have been recovered from the formation....

) of China during either the Bathonian

Bathonian

In the geologic timescale the Bathonian is an age or stage of the Middle Jurassic. It lasted from approximately 167.7 Ma to around 164.7 Ma...

 or the Callovian

Callovian

In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....

 (~165 Ma) in age.
The youngest sphenosuchian, Macelognathus

Macelognathus

Macelognathus is an extinct genus of sphenosuchian crocodile from the Late Jurassic. Originally it was believed be a theropod dinosaur. It lived in what is now Wyoming, in North America....

, is known from the Late Jurassic of North America during the Kimmeridgian

Kimmeridgian

In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....

, (155 - 150 Ma).

Phylogeny

The monophyly

Monophyly

In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 of the group is debated, although several synapomorphies characterize the clade, including extremely slender limbs, a compact carpus

Carpus

In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers , whereas those of the metacarpus do. The corresponding part of the foot is the tarsus...

 and an elongate coracoid process.

In 2002, Clark and Sues found a possible sphenosuchian clade of Dibothrosuchus

Dibothrosuchus

Dibothrosuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from several partial skeletons and skulls. These fossils were found in Lower Jurassic rocks of Yunnan, China...

, Sphenosuchus

Sphenosuchus

Sphenosuchus is an extinct genus of sphenosuchian from the Elliot Formation of South Africa, discovered and described early in the 20th century. The skull is excellently preserved but other than elements of the forelimb and isolated parts of the hind limb, the Sphenosuchus material is incomplete...

, and possibly Hesperosuchus

Hesperosuchus

Hesperosuchus is an extinct genus of crocodylomorph reptile that contains a single species, Hesperosuchus agilis. Remains of this sphenosuchian have been found in Late Triassic strata from Arizona and New Mexico....

and Saltoposuchus

Saltoposuchus

Saltoposuchus is an extinct genus of small , long- tailed crocodylomorph reptile , from the Norian of Europe. The name translated means "leaping crocodile". It has been proposed that Terrestrisuchus gracilis and Saltoposuchus connectens represent different ontogenetic stages of the same genus...

, with several other genera in unresolved positions (Kayentasuchus

Kayentasuchus

Kayentasuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin...

, Litargosuchus

Litargosuchus

Litargosuchus is an extinct genus of sphenosuchian crocodylomorph from the Early Jurassic of South Africa. Its remains were originally described by Gow and James Kitching in 1988 as belonging to Pedeticosaurus sp....

, Pseudhesperosuchus

Pseudhesperosuchus

Pseudhesperosuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin...

, and Terrestrisuchus

Terrestrisuchus

Terrestrisuchus is an extinct genus of early crocodylomorph that was about 50 cm long. Fossils have been found in Wales and date from the Late Triassic....

). 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. 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.

Below is a cladogram

Cladogram

A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

 modified from Nesbitt (2011). Sphenosuchians are marked by the green bracket.

Genera

Genus	Status	Age	Location	Unit	Notes	Images |-	Barberenasuchus Barberenasuchus Barberenasuchus is an extinct genus of early basal crocodylomorph. Fossils have been found from the Santa Maria Formation of southern Brazil of Late Triassic age. It is named in honor of Mário Costa Barberena.-References:* * *...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...	Brazil	Santa Maria Formation Santa Maria Formation The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It has a late Ladinian – early Carnian age , and is notable for its fossils of early dinosaurs, including the herrerasaur Staurikosaurus, the basal saurischian Teyuwasu, and the basal sauropodomorph...
Dibothrosuchus Dibothrosuchus Dibothrosuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from several partial skeletons and skulls. These fossils were found in Lower Jurassic rocks of Yunnan, China...	Valid	Early Jurassic Early Jurassic The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...	Mainland China	Lower Lufeng Series Lower Lufeng Series The Lower Lufeng Series is a Lower Jurassic sedimentary rock formation found in Yunnan, China. It has two units: the lower Dull Purplish Beds are of Hettangian age, and Dark Red Beds are of Sinemurian age. It is known for its fossils of early dinosaurs...
Dromicosuchus Dromicosuchus Dromicosuchus is an extinct genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It was found in Upper Triassic rocks of North Carolina, United States, and is known from a nearly complete skull and partial skeleton...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...	United States	Newark Supergroup
Dyoplax Dyoplax Dyoplax is an extinct genus of sphenosuchian crocodylomorph. Fossils have been found from the type locality within the upper Schilfsandstein Formation in Stuttgart-Feuerbach, Germany. The formation was deposited during the early Carnian stage of the Late Triassic 228 million years ago in a lagoonal...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...  (Carnian Carnian The Carnian is the lowermost stage of the Upper Triassic series . It lasted from about 228.7 till 216.5 million years ago . The Carnian is preceded by the Ladinian and is followed by the Norian... )	Germany	Schilfsandstein Formation
Hallopus Hallopus Hallopus was a prehistoric reptile, classified by O. C. Marsh in 1881 as a dinosaur. In fact it was probably a crocodilian or possibly a more primitive crurotarsan, and may be closely related to Junggarsuchus ....	Valid	Late Jurassic Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...	United States	Morrison Formation Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...	Possible synonym of Macelognathus
Hesperosuchus Hesperosuchus Hesperosuchus is an extinct genus of crocodylomorph reptile that contains a single species, Hesperosuchus agilis. Remains of this sphenosuchian have been found in Late Triassic strata from Arizona and New Mexico....	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...  (Carnian Carnian The Carnian is the lowermost stage of the Upper Triassic series . It lasted from about 228.7 till 216.5 million years ago . The Carnian is preceded by the Ladinian and is followed by the Norian... )	United States	Chinle Formation Chinle Formation The Chinle is a geologic formation that is spread across the U.S. states of northern Arizona, Nevada, Utah, western New Mexico, and western Colorado. The Chinle is controversially considered to be synonymous to the Dockum Group in eastern Colorado, eastern New Mexico, southwestern Kansas, the...
Junggarsuchus Junggarsuchus Junggarsuchus is an extinct genus of sphenosuchian crocodylomorph from the Middle Jurassic of China. The type species is J. sloani.-Anatomy:...	Valid	Middle Jurassic Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....	Mainland China	Shishugou Formation Shishugou Formation The Shishugou Formation is a geological formation in Xinjiang, China, whose strata date back to the Late Jurassic period. Dinosaur remains are among the fossils that have been recovered from the formation....
Kayentasuchus Kayentasuchus Kayentasuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin...	Valid	Early Jurassic Early Jurassic The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...  (Sinemurian Sinemurian In the geologic timescale, the Sinemurian is an age or stage in the Early or Lower Jurassic epoch or series. It spans the time between 196.5 ± 2 Ma and 189.6 ± 1.5 Ma...  - Pliensbachian Pliensbachian The Pliensbachian is an age of the geologic timescale or stage in the stratigraphic column. It is part of the Early or Lower Jurassic epoch or series and spans the time between 189.6 ± 1.5 Ma and 183 ± 1.5 Ma . The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian.The... )	United States	Kayenta Formation Kayenta Formation The Kayenta Formation is a geologic layer in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it is seen in the...
Litargosuchus Litargosuchus Litargosuchus is an extinct genus of sphenosuchian crocodylomorph from the Early Jurassic of South Africa. Its remains were originally described by Gow and James Kitching in 1988 as belonging to Pedeticosaurus sp....	Valid	Early Jurassic Early Jurassic The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...	South Africa	Elliot Formation Elliot Formation The Elliot Formation is a geological formation dating to roughly 210 to 190 million years ago and covering the Norian to Sinemurian stages. The Elliot Formation is found in South Africa and Lesotho and is a member of the Stormberg Group. It consists mainly of limestone, sandstone, and mudstone...
Macelognathus Macelognathus Macelognathus is an extinct genus of sphenosuchian crocodile from the Late Jurassic. Originally it was believed be a theropod dinosaur. It lived in what is now Wyoming, in North America....	Valid	Late Jurassic Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...	United States	Morrison Formation Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...
Parrishia Parrishia Parrishia is an extinct genus of sphenosuchian crocodylomorph that is currently considered a nomen dubium because of the lack of diagnostic features associated with it...	Nomen dubium Nomen dubium In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...	United States	Dockum Group Dockum Group The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much...	An indeterminate sphenosuchian known only from undiagnostic vertebrae
Pedeticosaurus Pedeticosaurus Pedeticosaurus is an extinct genus of sphenosuchian crocodylomorph from the Clarens Formation of South Africa. The type species is P. leviseuri....	Valid	Early Jurassic Early Jurassic The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...	South Africa	Elliot Formation Elliot Formation The Elliot Formation is a geological formation dating to roughly 210 to 190 million years ago and covering the Norian to Sinemurian stages. The Elliot Formation is found in South Africa and Lesotho and is a member of the Stormberg Group. It consists mainly of limestone, sandstone, and mudstone...
Phyllodontosuchus Phyllodontosuchus Phyllodontosuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from a skull and jaws from Lower Jurassic rocks of Yunnan, China...	Valid	Early Jurassic Early Jurassic The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...	Mainland China	Lower Lufeng Series Lower Lufeng Series The Lower Lufeng Series is a Lower Jurassic sedimentary rock formation found in Yunnan, China. It has two units: the lower Dull Purplish Beds are of Hettangian age, and Dark Red Beds are of Sinemurian age. It is known for its fossils of early dinosaurs...
Pseudhesperosuchus Pseudhesperosuchus Pseudhesperosuchus is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...  (Norian Norian The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in... )	Argentina	Los Colorados Formation Los Colorados Formation The Los Colorados Formation is a sedimentary rock formation found in La Rioja, Argentina. It has a Norian age , and is notable for its fossils of early dinosaurs, including the coelophysoid Zupaysaurus and the "prosauropods" Coloradisaurus, Lessemsaurus, and Riojasaurus.-Dinosaurs:Indeterminate...
Redondavenator Redondavenator Redondavenator is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from a partial upper jaw and left shoulder girdle found in rocks of the Norian-Rhaetian-age Upper Triassic Redonda Formation, northeastern New...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...	United States	Redonda Formation
Saltoposuchus Saltoposuchus Saltoposuchus is an extinct genus of small , long- tailed crocodylomorph reptile , from the Norian of Europe. The name translated means "leaping crocodile". It has been proposed that Terrestrisuchus gracilis and Saltoposuchus connectens represent different ontogenetic stages of the same genus...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...  (Norian Norian The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in... )	Germany  Switzerland	Löwenstein Formation Trossingen Formation Trossingen Formation The Trossingen Formation is a geological formation in Germany. It dates back to the late Norian.-Vertebrate fauna:Pterospondylus trielbae - "Vertebra."... Lossiemouth Sandstone Lossiemouth Sandstone The Lossiemouth Sandstone is a Late Triassic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation.-Paleofauna:-See also:* List of dinosaur-bearing rock formations...
Sphenosuchus Sphenosuchus Sphenosuchus is an extinct genus of sphenosuchian from the Elliot Formation of South Africa, discovered and described early in the 20th century. The skull is excellently preserved but other than elements of the forelimb and isolated parts of the hind limb, the Sphenosuchus material is incomplete...	Valid	Early Jurassic Early Jurassic The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...	South Africa	Elliot Formation Elliot Formation The Elliot Formation is a geological formation dating to roughly 210 to 190 million years ago and covering the Norian to Sinemurian stages. The Elliot Formation is found in South Africa and Lesotho and is a member of the Stormberg Group. It consists mainly of limestone, sandstone, and mudstone...
Terrestrisuchus Terrestrisuchus Terrestrisuchus is an extinct genus of early crocodylomorph that was about 50 cm long. Fossils have been found in Wales and date from the Late Triassic....	Valid.	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
Trialestes Trialestes Trialestes is an extinct genus of Late Triassic crocodylomorph that lived in South America. It has been classified as a dinosaur in the past due it being adapted as a terrestrial, running carnivore. It is classified in Sphenosuchia, which were early relatives of crocodilians.- External links :* at...	Valid	Late Triassic Late Triassic The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...	Argentina	Ischigualasto Formation	Known specimens may represent basal crocodylomorphs and dinosaurs