Atoposaurus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of crocodylomorph

Crocodylomorpha

The Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...

. It is the type genus

Type genus

In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

 of the family Atoposauridae

Atoposauridae

Atoposauridae is a family of crocodile-like archosaurs. Members of the family have been found from France, Spain, Portugal, Romania, Germany, Kazakhstan, the United Kingdom, the United States, Cameroon, and Thailand.-Phylogeny:...

. Fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s have been found that were 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...

 in age from two distinct species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 in France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

.

One interesting feature of Atoposaurus is that it lacked dorsal scutes

Scute

A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...

, a common characteristic of atoposaurids as well as most crurotarsans

Crurotarsi

The Crurotarsi are a group of archosauriformes, represented today by the crocodiles,...

. The absence of scutes, along with its relatively small size (specimens reach lengths of up to 17 cm), narrow supratemporal fossae, wide occipital region

Occipital bone

The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoidal in shape and curved on itself...

, thin postorbital bar

Postorbital bar

The postorbital bar is a bone which runs around the eyesocket of strepsirrhine primates. This is in contrast to the higher primates, haplorrhine, which have evolved fully enclosed sockets to protect their eyes....

, and smooth ornamentation, has led some paleontologists to believe that it is perhaps a juvenile form of another genus within Atoposauridae, most likely Alligatorellus

Alligatorellus

Alligatorellus is a genus of atoposaurid crocodyliform found in France that was related to Atoposaurus.A skeleton of Alligatorellus has also been found in the Solnhofen Limestone of Kelheim, Germany. The limestone was deposited in a marine environment and the individual may have washed into a...

.

External links

• Atoposaurus in the Paleobiology Database
  Paleobiology Database
  ' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...