Temporal range: Late Carboniferous - Middle Permian,
PreꞒ
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O
S
D
C
P
T
J
K
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Fossil skeleton of Cotylorhynchus romeri
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Clade:
Synapsida
Clade:
†Caseasauria
Family:
†Caseidae Williston, 1912
Genera
Alierasaurus
Angelosaurus
Arisierpeton
Callibrachion
Casea
Caseoides
Caseopsis
Cotylorhynchus
Datheosaurus
Ennatosaurus
Eocasea
Euromycter
Lalieudorhynchus
Martensius
Oromycter
Phreatophasma
Ruthenosaurus
Trichasaurus
Caseidae are an extinct family of basal synapsids that lived from the Late Carboniferous to Middle Permian between about 300 and 265 million years ago. Fossils of these animals come from the south-central part of the United States (Texas, Oklahoma, and Kansas), from various parts of Europe (European Russia, France, Germany, Sardinia, and Poland), and possibly from South Africa if the genus Eunotosaurus is indeed a caseid as some authors proposed in 2021. Caseids show great taxonomic and morphological diversity. The most basal taxa were small insectivorous and omnivorous forms that lived mainly in the Upper Carboniferous and Lower Permian, such as Eocasea, Callibrachion, and Martensius. This type of caseid persists until the middle Permian with Phreatophasma and may be Eunotosaurus. During the early Permian, the clade is mainly represented by many species that adopted a herbivorous diet. Some have evolved into gigantic forms that can reach 6–7 metres (20–23 ft) in length, such as Cotylorhynchus hancocki and Alierasaurus ronchii, making them the largest Permian synapsids. Caseids are considered important components of early terrestrial ecosystems in vertebrate history because the numerous herbivorous species in this family are among the first terrestrial tetrapods to occupy the role of primary consumer. The caseids experienced a significant evolutionary radiation at the end of the early Permian, becoming, with the captorhinid eureptiles, the dominant herbivores of terrestrial ecosystems in place of the edaphosaurids and diadectids.
In 2016 and 2022, paleontologists proposed a semiaquatic lifestyle for the most derived genera like Cotylorhynchus and Lalieudorhynchus, but this hypothesis is disputed by other researchers.
With a fossil record spanning from the Late Carboniferous to the Middle Permian, caseids are one of the basal synapsids groups (formerly known as “pelycosaur”) having the largest stratigraphic range. They also represent one of only two basal synapsid groups (along with the Varanopidae) to survive in therapsid-dominated terrestrial communities. Thus, the last known caseids come from the strata of the middle Permian (Upper Roadian-Wordian) of France and European Russia, where they cohabited notably with dinocephalians.[nb 1] These last caseids still show a certain morphological diversity with medium to large herbivores (Ennatosaurus and Lalieudorhynchus), as well as small predatory or omnivorous forms such as Phreatophasma and possibly Eunotosaurus. Caseids are so far unknown in Upper Permian strata and probably disappeared at the end of the Middle Permian. They were replaced by pareiasaurs (with similar dentition) and dicynodonts.
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Caseidae are an extinct family of basal synapsids that lived from the Late Carboniferous to Middle Permian between about 300 and 265 million years ago...
insectivorous or carnivorous Eothyrididae, and the large, herbivorous Caseidae. These two groups share a number of specialised features associated with...
Ennatosaurus tecton (Synapsida: Caseidae) from the Middle Permian of Russia and the evolutionary relationships of Caseidae". Journal of Vertebrate Paleontology...
end of the snout is wider and more rounded than that of the more derived caseidae. The palate is broad and plate-like. A narrow interpterygoid vacuity divides...
2004. Order Pelycosauria* Suborder Caseasauria Family Eothyrididae Family Caseidae Suborder Eupelycosauria Family Varanopidae Family Ophiacodontidae Family...
of Caseidae published by Maddin et al. in 2008. In 2015, Romano and Nicosia published the first cladistic study including almost all the Caseidae (with...
thoroughly attached to the bone of the skull and jaw than in other members of Caseidae. The first and second teeth of the premaxilla show distinct wear facets...
Alfred Romer in 1956 and then as a member of a basal synapsid family called Caseidae starting with Everett C. Olson in 1962. Olson's classification was later...
; Nicosia, U (2017). "New material of Alierasaurus ronchii (Synapsida, Caseidae) from the Permian of Sardinia (Italy), an dits phylogenetic affinities"...
were among the largest animals of the Permian period; only the biggest Caseidae and Pareiasauridea reaching them in size. Dinocephalians were generally...
large caniniform tooth in front of the maxilla. Eothyridids share with the Caseidae a number of specialised features associated with the morphology of the...
Archosauria Class Synapsida Order Pelycosauria Family Eothyrididae Family Caseidae Family Varanopidae Family Ophiacodontidae Family Edaphosauridae Family...
Ennatosaurus tecton (Synapsida: Caseidae) from the Middle Permian of Russia and the evolutionary relationships of Caseidae". Journal of Vertebrate Paleontology...
S2CID 253542331. Romano, M.; Nicosia, U. (2015). "Cladistic analysis of Caseidae (Caseasauria, Synapsida): using the gap-weighting method to include taxa...
Ennatosaurus tecton (Synapsida: Caseidae) from the Middle Permian of Russia and the evolutionary relationships of Caseidae". Journal of Vertebrate Paleontology...
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