Crocodiles, alligators

Crurotarsi

The Crurotarsi (with their shared derived crurotarsal ankle [1 below]) are divided into three groups: the Phytosauria, the Ornithosuchia, and the Suchia.

Phytosauria

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  The primitive phytosaur Paleorhinus from the Malari Formation of India. Based on Chatterjee (1978).
  

  Skull of juvenile phytosaur from the Newark basin (Newark Supergroup), North Bergen, NJ.	Skull of phytosaur as found from the Fundy basin (Newark Supergroup), Digby, Nova Scotia, Canada.

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  	The Phytosauria have the shared derived character of an elongated snout with nostrils that have moved posteriorly (like in a whale) (7). They were very common semiaquatic forms extremely convergent on modern crocodiles in their overall habitus. They can at once be distinguished from crocodiles by the nostrils, which are located towards the rear of the snout, often just in front of the eyes. Rutiodon is a common example from the Newark and the Chinle. They became extinct at the end of the Triassic.
  Discovery of a phytosaur skull in the Chinle Group, Petrified Forest National Park. Kevin Padian, leader of the expedition is on right. The phytosaur skull is the black rubble they are staring at.	Manus and pes impression of a phytosaur (the track is called Apatopus), from the Newark Supergroup, Newark basin, Oaks, PA.

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  The Ornithosuchia were fairly robust carnivores with a large head. They have the shared derived condition of a large diastema (gap in the tooth row) between the premaxilla and the maxilla (6, above; d in figure below). They are known from only a few skeletons, mostly from England, such as Ornithosuchus. They had a tendency to develop small forelegs and probably some degree of bipedalism.
  

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  Ornithosuchus, based on Walker (1964).
  

• The Suchia

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  The Suchia have the shared derived character of a reduced and triangular lower temporal opening (2). Three groups comprise the Suchia: 1) the Rauisuchia; 2) the Aetosauria; and 3) the Crocodylomorpha. The Rauisuchia were the largest and fiercest of the carnivores of the Triassic. Some species became gigantic with some forms having skulls more than a meter long. Their shared derived character is a slit between the premaxilla and maxilla (5). For the most part they remained quadrupedal. Postosuchus from the Chinle Group and the Newark Supergroup of North Carolina is an example.
  

Skeleton of Postosuchus, after Long and Muray (1996).

Skull of Postosuchus; after Long and Muray (1996).

The skull of Postosuchus clearly shows the triangular lower temporal fenestra that is the shared derived character of the Suchia, as well as the slit between the maxilla and premaxilla that is the shared derived character of the Rauisuchia. Abbreviations are - a, antorbital fenestra; lt, lower temporal opening; o, orbit.

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  The foot of Postosuchus clearly has a crurotarsal ankle that can be seen on the photograph to the right. Abbreviations are: c, calcaneum; f, fibula; t, tibia. In this particular individual, the calcaneum and astragalus have fused together because of arthritis. There are also several bony outgrowths on the phalanges that were probably quite painful in life.

  Foot of Postosuchus from North Carolina

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  The Aetosauria were herbivorous armored forms. They have a pig-like snout and peg-like teeth. Their shared derived character is the heavy coat of armor covering the back (3). Desmatosuchus from the Chinle and Stegomus from the Newark of New Jersey and Connecticut is a good example.
  

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  The Crocodylomorpha are by far the most diverse forms and are still with us today. The shared derived character for the group is to have a pair of very elongated carpal bones (the radiale and ulnare [4]). These probably act to add an extra joint to the fore leg increasing its swing. Triassic crocodylomorphs were very graceful, slender forms - more reminiscent of a greyhound than a true crocodile. Some modern crocodiles such as one form from Australia can still move very quickly and can even run in a full gallop [fig]. This was almost certainly true of the Triassic forms. It was not until after the extinction of the phytosaurs at the end of the Triassic that the crocodylomorphs evolved into crocodiles of modern aspect, although fully terrestrial forms persist into the Cretaceous. Some Triassic (and later) forms even evolved into herbivorous forms and forms with very mammal-like teeth.
  
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  Dwarf West African Crocodile in a highwalk mode of locomotion.
  

  Erpetosuchus originally from Scotland and recently found in the Newark Supergroup of Connecticut is an example of one of these early, terrestrial crocodylomorphs. On the right, "a" is the skull of Erpetosuchus from Connecticut, and "b" is the skull from Scotland (based on Olsen et al., in prep.). Scale is 5 mm.

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  Reconstruction of a galloping Erpetosuchus.
  
  
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  IV. Ornithodira The Ornithodira are the bird-like archosaurs and they include dinosaurs, pterosaurs and incompletely known forms. As stated before their shared derived characteristic is a mesotarsal ankle.
  
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  The Pterosauria are the most completely known of the non-dinosaurian ornithodirans to arise in the Triassic. Their earliest appearance is from the Late Triassic of northern Italy, Germany, and Greenland.
  
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  Their shared derived character is the very elongate finger that supports a wing. We will look at them in more detail in the next lecture.
  
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  Another early ornithodiran is Lagosuchus, known from several partial skeletons from the Ischigualasto Formation. It is a small lightly built animal with very long legs.
  
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  Reconstruction of the skeleton of Lagosuchus, after Paul (1988). The brown color indicates the distribution of light armor and the manus is not preserved in the existing material (green).
  

Pelvis of Lagosuchus; after Arcucci (1996).

Crurotarsi

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  Phytosauria (Onderorde) Familie Phytosauridae
  
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  Ornithosuchida (Onderorde) Familie Ornithosuchidae
  
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  Pestosuchidae (Familie) Pestosuchus (Soort) zie afb. hierboven
  
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  Rauisuchia (Onderorde) Families: Poposauridae; Rauisuchidae
  
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  Aetosauria (Onderorde) Families: Aetosauridae; Stagonolepididae
  
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  Crocodylomorpha (Superorde)
  

http://tsjok45.wordpress.com/2012/12/28/krodillen/ 

http://en.wikipedia.org/wiki/List_of_crurotarsans 
List of crurotarsans

From Wikipedia, the free encyclopedia

This list of crurotarsans is a comprehensive listing of all genera that have ever been included in the clade Crurotarsi, excluding purely vernacular terms. Under some definitions Crurotarsi includes all archosaurs, but this list excludes archosaur genera that are included in Avemetatarsalia (pterosaurs, nonavian dinosaurs, and birds). The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium), or were not formally published (nomen nudum), as well as junior synonyms of more established names, and genera that are no longer considered crurotarsan. Extinct taxa are denoted with a dagger (†). The list contains 527 names, of which approximately 422 are considered either valid crurotarsan genera or nomina dubia.

Scope and terminology

There is no official, canonical list of crurotarsan genera, but one of the most thorough attempts can be found on the Crurotarsi section of Mikko Haaramo's Phylogeny Archive. That list has been supplemented with the Paleofile listing for Crocodylomorpha.

Naming conventions and terminology follow the International Code of Zoological Nomenclature. Technical terms used include:

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  Junior synonym: A name which describes the same taxon as a previously published name. If two or more genera are formally designated and the type specimens are later assigned to the same genus, the first to be published (in chronological order) is the senior synonym, and all other instances are junior synonyms. Senior synonyms are generally used, except by special decision of the ICZN, but junior synonyms cannot be used again, even if deprecated. Junior synonymy is often subjective, unless the genera described were both based on the same type specimen.
  
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  Nomen nudum (Latin for "naked name"): A name that has appeared in print but has not yet been formally published by the standards of the ICZN. Nomina nuda (the plural form) are invalid, and are therefore not italicized as a proper generic name would be. If the name is later formally published, that name is no longer a nomen nudum and will be italicized on this list. Often, the formally published name will differ from any nomina nuda that describe the same specimen. In this case, these nomina nuda will be deleted from this list in favor of the published name.
  
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  Preoccupied name: A name that is formally published, but which has already been used for another taxon. This second use is invalid (as are all subsequent uses) and the name must be replaced. As preoccupied names are not valid generic names, they will also go unitalicized on this list.
  
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  Nomen dubium (Latin for "dubious name"): A name describing a fossil with no unique diagnostic features. This can be an extremely subjective and controversial designation and is to be used cautiously.
  

Contents:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z — See also

A

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  †Acaenasuchus
  
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  †Acherontisuchus
  
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  †Acompsosaurus
  
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  †Acynodon
  
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  †Adamanasuchus
  
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  †Adamantinasuchus
  
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  †Adzhosuchus
  
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  †Aegisuchus
  
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  †Aegyptosuchus
  
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  †Aeolodon — junior synonym of Steneosaurus
  
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  †Aetobarbakinoides
  
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  †Aetosauroides
  
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  †Aetosaurus
  
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  †Aggiosaurus
  
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  †Aigialosuchus
  
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  †Akanthosuchus
  
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  †Aktiogavialis
  
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  †Albertochampsa
  
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  †Aldabrachampsus
  

An American Alligator.

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  Alligator
  
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  †Alligatorellus
  
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  †Alligatorium
  
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  †Allodaposuchus
  
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  †Allognathosuchus
  
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  †Amargasuchus
  
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  †Amphicotylus
  
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  †Anatosuchus
  
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  †Angistorhinopsis — junior synonym of Nicrosaurus
  
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  †Angistorhinus
  
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  †Anglosuchus
  
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  †Anteophthalmosuchus
  
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  †Arambourgia
  
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  †Arambourgisuchus
  
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  †Araripesuchus
  
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  †Archaeosuchus — preoccupied by a synapsid, renamed Protosuchus
  
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  †Arenysuchus
  
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  †Arganarhinus
  
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  †Arganasuchus
  
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  †Argentinosuchus — junior synonym of Stagonolepis
  
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  †Argochampsa
  
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  †Arizonasaurus
  
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  †Armadillosuchus^[1]
  
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  Aromosuchus — junior synonym of Paleosuchus
  
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  †Arribasuchus — junior synonym of Pseudopalatus
  
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  †Artzosuchus
  
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  †Asiatosuchus
  
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  †Atacisaurus — junior synonym of Pristichampsus
  
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  †Atlantosuchus
  
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  †Atoposaurus
  
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  †Australosuchus
  
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  †Ayllusuchus
  

B

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  †Baharijodon
  
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  †Balanerodus
  
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  †Barberenasuchus
  
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  †Barcinosuchus
  
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  †Barinasuchus^[2]
  
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  †Baroqueosuchus — junior synonym of Protosuchus
  
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  †Barreirosuchus
  
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  †Baru
  
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  †Baryphracta
  

An artist's re-creation of an Batrachotomus kupferzellensis

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  †Basutodon
  
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  †Batrachotomus
  
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  †Baurusuchus
  
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  †Belodon
  
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  †Bergisuchus
  
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  †Bernissartia
  
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  †Bombifrons — junior synonym of Crocodylus
  
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  †Borealosuchus
  
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  †Bottosaurus
  
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  †Boverisuchus — junior synonym of Pristichampsus
  
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  †Brachychampsa
  
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  †Brachygnathosuchus
  
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  †Brachysuchus
  
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  †Brachytaenius — junior synonym of Geosaurus
  
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  †Brachyuranochampsa
  
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  †Brasileosaurus
  
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  †Bretesuchus
  
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  †Brillanceausuchus
  
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  †Bromsgroveia
  
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  †Bystrowisuchus
  

C

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  Caiman
  

A Yacare caiman (Jacaré) from Brazil.

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  †Caimanoidea — junior synonym of Alligator
  
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  †Caimanoideus — lapsus calami of Caimanoidea
  
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  †Caimanoeda — lapsus calami of Caimanoidea
  
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  †Caimanosuchus — junior synonym of Diplocynodon
  
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  Caigator — junior synonym of Alligator
  
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  †Caipirasuchus
  
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  †Calsoyasuchus
  
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  †Calyptosuchus
  
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  †Campinasuchus
  
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  †Candidodon
  
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  †Capellineosuchus — misspelling of Capelliniosuchus
  
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  †Capelliniosuchus — once thought to be a metriorhynchid, now known to be a mosasaur
  
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  †Carandaisuchus
  
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  †Caririsuchus
  
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  †Caryonosuchus
  
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  †Centemodon
  
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  †Ceratosuchus
  
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  †Cerrejonisuchus
  
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  Champsa — referred to both Alligator and Caiman
  
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  †Champse — junior synonym of Crocodylus
  
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  †Charactosuchus
  
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  †"Chasmatosuchus" — preoccupied by a proterosuchid archosaur, referred to Jaikosuchus
  
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  †Chatterjeea — junior synonym of Shuvosaurus
  
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  †Chenanisuchus
  
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  †Chiayusuchus
  
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  †Chilenosuchus
  
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  †Chimaerasuchus
  
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  †Chrysochampsa
  
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  †Cladeiodon — possible senior synonym of Teratosaurus
  
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  †Clarencea
  
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  †Coahomasuchus
  
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  †Coburgosuchus — junior synonym of Nicrosaurus
  
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  †Coelosuchus
  
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  †Collilongus^[3]
  
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  †Colossoemys
  
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  †Comahuesuchus
  
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  †Congosaurus
  
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  †Coringasuchus^[4]
  
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  †Cricosaurus
  
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  †Crocodilaemus
  
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  Crocodylus
  
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  †Ctenosauriscus
  
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  Ctenosaurus — preoccupied by extant iguanid, referred to Ctenosauriscus
  
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  †"Cunampaia" — a nomen dubium; originally considered a phorusrhacid bird, probably a mesoeucrocodylian
  
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  †Cynodontosuchus
  
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  Cynosuchus — junior synonym of Caiman
  
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  †Cystosaurus
  

D

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  †Dacosaurus — lapsus calami of Dakosaurus
  
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  †Dakosaurus
  

An artist's reconstruction of Dakosaurus andiniensis.

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  †Dakotasuchus
  
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  †Dasygnathus — synonym of Ornithosuchus
  
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  †Decuriasuchus
  
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  †Deinosuchus
  
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  †Denazinosuchus
  
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  †Desamatosuchus — lapsus calami of Desmatosuchus
  
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  †Desmatosuchus
  
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  †Dianchungosaurus
  
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  †Dianosuchus
  
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  †Dibothrosuchus
  
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  †Dinosuchus
  
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  †Diplocynodon
  
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  †Diplocynodus — junior synonym of Diplocynodon
  
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  †Diplosaurus
  
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  †Dolichobrachium
  
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  †Dolichochampsa
  
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  †Dollosuchoides
  
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  †Dollosuchus
  
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  †Dongusia
  
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  †Dongusuchus
  
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  †Doratodon
  
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  †Doswellia
  
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  †Dromicosuchus
  
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  †Duerosuchus
  
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  †Dyoplax
  
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  †Dyrosaurus
  
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  †Dzungarisuchus