Microchampsa
Encyclopedia
Microchampsa is an extinct genus
of protosuchia
n crocodylomorph that existed during the Early Jurassic
. Fossil
s have been found from stratum 6 of the Dahuangtian locality, an outcrop of the Lower Red Beds of the Lufeng Formation in Yunnan
, China
. Parts of the postcranial skeleton, such as the dorsal osteoderm
s, vertebrae, ribs, and bones of the manus, are known. The dorsal osteoderms of the lumbar region are fused to double headed ribs. All osteoderms are rectangular and overlap each other.
Microchampsa was named in 1951 on the basis of an incomplete skeleton consisting of cervical and anterior dorsal vertebrae as well as ribs and three rows of dorsal osteoderms. Three other specimens of crocodylomorphs described in 1965 also seemed to display three rows of osteoderms, and as a result were assigned to the genus Microchampsa. However, later studies revealed that the specimens had only two rows of osteoderms that more closely resembled those of the genus Platyognathus
, and that the presence of three rows of osteoderms in the holotype of Microchampsa may have been an artifact of preservation. However, this hypothesis is speculative as the holotype of Microchampsa had since been lost by the time of the studies.
It was assigned to the suborder Protosuchia
in 1965 and the family
Notochampsidae in 1992. However, later studies argued that it is a nomen dubium
due to the lack of diagnostic material in the incompletely known remains. Thus it can only be regarded as a poorly known protosuchian.
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 protosuchia
Protosuchia
Protosuchia is a group of extinct Mesozoic crocodyliforms. They were small in size and terrestrial. In phylogenetic terms, Protosuchia is considered an informal group because it is a grade of basal crocodyliforms, not a true clade....
n crocodylomorph that existed during the Early Jurassic
Early Jurassic
The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...
. Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s have been found from stratum 6 of the Dahuangtian locality, an outcrop of the Lower Red Beds of the Lufeng Formation 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...
, 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...
. Parts of the postcranial skeleton, such as the dorsal osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...
s, vertebrae, ribs, and bones of the manus, are known. The dorsal osteoderms of the lumbar region are fused to double headed ribs. All osteoderms are rectangular and overlap each other.
Microchampsa was named in 1951 on the basis of an incomplete skeleton consisting of cervical and anterior dorsal vertebrae as well as ribs and three rows of dorsal osteoderms. Three other specimens of crocodylomorphs described in 1965 also seemed to display three rows of osteoderms, and as a result were assigned to the genus Microchampsa. However, later studies revealed that the specimens had only two rows of osteoderms that more closely resembled those of the genus Platyognathus
Platyognathus
Platyognathus is an extinct genus of protosuchian crocodylomorph. Fossils are known from the Early Jurassic Lower Lufeng Formation in Yunnan, China and belong to the type and only species, P. hsui.-Description:...
, and that the presence of three rows of osteoderms in the holotype of Microchampsa may have been an artifact of preservation. However, this hypothesis is speculative as the holotype of Microchampsa had since been lost by the time of the studies.
It was assigned to the suborder Protosuchia
Protosuchia
Protosuchia is a group of extinct Mesozoic crocodyliforms. They were small in size and terrestrial. In phylogenetic terms, Protosuchia is considered an informal group because it is a grade of basal crocodyliforms, not a true clade....
in 1965 and the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Notochampsidae in 1992. However, later studies argued that it is a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
due to the lack of diagnostic material in the incompletely known remains. Thus it can only be regarded as a poorly known protosuchian.
External links
- Microchampsa in the Paleobiology DatabasePaleobiology 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...