''Atoposaurus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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. Extinct crocodylomorphs were considerably mor ...

. It is the

type genus In biological taxonomy, the type genus (''genus typica'') 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-bearin ...

of the family

Atoposauridae Atoposauridae is an extinct family of neosuchian crocodyliforms, known from the Jurassic and Cretaceous of Eurasia. Characterised by their small size and their heterodont (having multiple tooth types) dentition, they are thought to have lived in ...

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 preserve ...

s have been found that were

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

in age from two distinct

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

. 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 thought ...

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

supratemporal fossa Temporal fenestrae are openings in the temporal region of the skull of some amniotes, behind the orbit (eye socket). These openings have historically been used to track the evolution and affinities of reptiles. Temporal fenestrae are commonly (al ...

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 lies over the occipital lobes of the cere ...

, 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''.

History of the holotype

The

Teylers Museum Teylers Museum () is an Art museum, art, Natural history museum, 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 ...

has a

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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 laticeps'', ''

Homeosaurus ''Homoeosaurus'' is an extinct genus of rhynchocephalian reptile, known from the Late Jurassic-earliest Cretaceous of Europe, with specimens being reported from France ( Canjuers Lagerstatte), England (Purbeck Group) and Germany (Solnhofen Limest ...

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 ) is a genus of extinct 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 reptile and one of the first prehis ...

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 in Frankfurt am ...

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

References

External links

''Atoposaurus''
in the

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

{{Taxonbar, from=Q4817431 Late Jurassic crocodylomorphs Extinct animals of Europe Atoposauridae Fossil taxa described in 1850 Prehistoric pseudosuchian genera