Owenettidae
Encyclopedia
Owenettidae is an extinct family
of procolophonia
n parareptiles. Fossil
s have been found primarily from Africa
and Madagascar
, with one genus present from South America
. It is the sister taxon to the family Procolophonidae.
The family was constructed in 1939 for the type genus
Owenetta
. Since then several other genera have been assigned to Owenettidae, including Barasaurus and Saurodektes. The oldest known owenettid, Owenetta rubidgei, dates back to the Wuchiapingian
stage of the Late Permian
. It and two other owenettids, Barasaurus and Saurodektes, have been found from the Beaufort Group
in the Karoo Basin
of South Africa
. These strata span the Permo-Triassic boundary and provide evidence for the great faunal change that occurred as a result of the Permian–Triassic extinction event. Although most owenettids lived during the Permian, remains of some taxa such as "Owenetta" kitchingorum (soon to be placed within its own genus) extend the temporal range of the family into the Triassic
. The youngest known owenettid is Candelaria
from the Santa Maria Formation
of Brazil
, which lived during the Ladinian
stage of the Middle Triassic
.
is known. In regards to cranial anatomy, there is no contact between the postorbital
and parietal bone
s as a result of enlarged postfrontal bones, and the skull table is formed partly from large supratemporals lateral to the parietal bones.
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...
of procolophonia
Procolophonia
The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria but are now considered a clade of Parareptilia...
n parareptiles. Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s have been found primarily from Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, with one genus present from South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. It is the sister taxon to the family Procolophonidae.
The family was constructed in 1939 for 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...
Owenetta
Owenetta
Owenetta is an extinct genus of basal procolophonian parareptile. Fossils have been found from the Beaufort Group in the Karoo Basin of South Africa. Although most procolophonians lived during the Triassic, Owenetta existed during the Wuchiapingian and Changhsingian stages of the Late Permian as...
. Since then several other genera have been assigned to Owenettidae, including Barasaurus and Saurodektes. The oldest known owenettid, Owenetta rubidgei, dates back to the Wuchiapingian
Wuchiapingian
In the geologic timescale, the Wuchiapingian or Wujiapingian is an age or stage of the Permian. It is also the lower or earlier of two subdivisions of the Lopingian epoch or series. The Wuchiapingian spans the time between 260.4 ± 0.7 and 253.8 ± 0.7 million years ago...
stage of the Late Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
. It and two other owenettids, Barasaurus and Saurodektes, have been found from the Beaufort Group
Beaufort Group
The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup of geological strata in Southern Africa. It follows conformably after the Ecca Group and consists essentially of sandstones and shales, deposited in the Karoo Basin from the Middle Permian to the early part of the...
in the Karoo Basin
Karoo
The Karoo is a semi-desert region of South Africa. It has two main sub-regions - the Great Karoo in the north and the Little Karoo in the south. The 'High' Karoo is one of the distinct physiographic provinces of the larger South African Platform division.-Great Karoo:The Great Karoo has an area of...
of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. These strata span the Permo-Triassic boundary and provide evidence for the great faunal change that occurred as a result of the Permian–Triassic extinction event. Although most owenettids lived during the Permian, remains of some taxa such as "Owenetta" kitchingorum (soon to be placed within its own genus) extend the temporal range of the family into 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...
. The youngest known owenettid is Candelaria
Candelaria barbouri
Candelaria barbouri was the first procolomorph discovered in the geopark of Paleorrota, in the town of Candelária, by Llewellyn Ivor Price in 1946. It was about long and lived during the Ladinian in the Middle Triassic, about 235 million years ago....
from the Santa Maria Formation
Santa Maria Formation
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It has a late Ladinian – early Carnian age , and is notable for its fossils of early dinosaurs, including the herrerasaur Staurikosaurus, the basal saurischian Teyuwasu, and the basal sauropodomorph...
of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, which lived during the Ladinian
Ladinian
The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between 237 ± 2 Ma and 228 ± 2 Ma...
stage of the Middle Triassic
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma...
.
Description
Owenettids were relatively small procolophonians that possessed broad heads and robust bodies. The family shares several synapomorphies that separate it from other related procolophonomorphs. The absence of an entepicondylar foramen is diagnostic to all members from which the humerusHumerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
is known. In regards to cranial anatomy, there is no contact between the postorbital
Postorbital
The postorbital is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some vertebrates, the postorbital is fused with the postfrontal...
and parietal bone
Parietal bone
The parietal bones are bones in the human skull which, when joined together, form the sides and roof of the cranium. Each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin pariet-, wall....
s as a result of enlarged postfrontal bones, and the skull table is formed partly from large supratemporals lateral to the parietal bones.
External links
- Owenettidae 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...