Pachysuchus
Encyclopedia
Pachysuchus is an extinct genus
of crurotarsan from the Early Jurassic
of China
. It is known from a poorly preserved partial rostrum
that was described from the Lower Lufeng Series
in Yunnan
by paleontologist C.C. Young in 1951. Young identified the rostrum as that of a phytosaur
, a long-snouted crocodile-like crurotarsan. Phytosaurs were common in the Triassic
, but none are known from the Jurassic
. They are thought to have gone extinct during the Triassic-Jurassic extinction event
. The rostrum from which Young described the specimen has since been lost, and his first description of the genus has been questioned. The poor preservation of the specimen and its presence in Jurassic beds makes it doubtful that Pachysuchus is a phytosaur.
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 crurotarsan from the Early Jurassic
Early Jurassic
The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...
of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. It is known from a poorly preserved partial rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
that was described from the 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...
in Yunnan
Yunnan
Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with...
by paleontologist C.C. Young in 1951. Young identified the rostrum as that of a phytosaur
Phytosaur
Phytosaurs are an extinct group of large semi-aquatic Late Triassic archosaurs. Phytosaurs belong to the family Phytosauridae and the order Phytosauria. They were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodiles in size, appearance, and lifestyle, an example...
, a long-snouted crocodile-like crurotarsan. Phytosaurs were common 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...
, but none are known from the Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
. They are thought to have gone extinct during the Triassic-Jurassic extinction event
Triassic-Jurassic extinction event
The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, , and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. In the seas a whole class and twenty percent of all marine families...
. The rostrum from which Young described the specimen has since been lost, and his first description of the genus has been questioned. The poor preservation of the specimen and its presence in Jurassic beds makes it doubtful that Pachysuchus is a phytosaur.