''Atoposaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, cro ...

. It is the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal f ...

of the family Atoposauridae.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s have been found that were

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

in age from two distinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

and

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

. One interesting feature of ''Atoposaurus'' is that it lacked dorsal scutes, a common characteristic of atoposaurids as well as most

crurotarsans Crurotarsi is a clade of archosauriform reptiles that includes crocodilians and stem-crocodilians and possibly bird-line archosaurs too if the extinct, crocodile-like phytosaurs are more distantly related to crocodiles than traditionally though ...

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

supratemporal fossa An infratemporal fenestra, also called the lateral temporal fenestra or simply temporal fenestra, is an opening in the skull behind the orbit in some animals. It is ventrally bordered by a zygomatic arch. An opening in front of the eye sockets, ...

e, wide

occipital region The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cereb ...

, thin

postorbital bar The postorbital bar (or postorbital bone) is a bony arched structure that connects the frontal bone of the skull to the zygomatic arch, which runs laterally around the eye socket. It is a trait that only occurs in mammalian taxa, such as most strep ...

, 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'' is an extinct 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 d ...

''.

History of the holotype

The

Teylers Museum Teylers Museum () is an art, natural history, and science museum in Haarlem, Netherlands. Established in 1778, Teylers Museum was founded as a centre for contemporary art and science. The historic centre of the museum is the neoclassical Oval R ...

has a

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen ''Atoposaurus oberndorfi'' that was bought by curator J.G.S. van Breda in 1863 from Adam August Krantz (1809-1872), dealer in minerals in Bonn from 1850 onwards. The purchase was made along with the other holotypes ''

Sapheosaurus ''Sapheosaurus'' was an extinct genus of Late Jurassic sphenodont. Its skull was longer and narrower than that of ''Homoeosaurus''. It was classified as a genus of sapheosaur by Michael Benton in 1985. It reached a length of 70 cm from snout ...

laticeps'', '' Homeosaurus maximilliani'', ''

Rhamphorhynchus ''Rhamphorhynchus'' (, from Ancient Greek ''rhamphos'' meaning "beak" and ''rhynchus'' meaning "snout") is a genus of long-tailed pterosaurs in the Jurassic period. Less specialized than contemporary, short-tailed pterodactyloid pterosaurs such ...

gemmingi'', ''

Pterodactylus ''Pterodactylus'' (from Greek () meaning 'winged finger') is an extinct genus of pterosaurs. It is thought to contain only a single species, ''Pterodactylus antiquus'', which was the first pterosaur to be named and identified as a flying rept ...

longirostris'' and ''Pterodactylus meyeri'', based on the book ''Zur Fauna der Vorwelt'' (1860) by

Christian Erich Hermann von Meyer Christian Erich Hermann von Meyer (3 September 1801 – 2 April 1869), known as Hermann von Meyer, was a German palaeontologist. He was awarded the 1858 Wollaston medal by the Geological Society of London. Life He was born at Frankfurt am Ma ...

.Research Bert Sliggers, conservator Paleontological cabinet Teylers Museum, 2012

References

External links

''Atoposaurus''
in the

Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ...

Late Jurassic crocodylomorphs Extinct animals of Europe Neosuchians Fossil taxa described in 1850 Prehistoric pseudosuchian genera {{Jurassic-reptile-stub