Caseidae

rdf:langString Caseidae

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rdf:langString Williston, 1912

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rdf:langString Left: paleogeographic map of Earth at the end of the Paleozoic showing the known distribution of caseid synapsids. Right: close-up of the paleogeographic location of the caseid sites. 1 and 2 Ennatosaurus tecton, Arkhangelsk Oblast, Russia, late Roadian – early Wordian ; 3 Phreatophasma aenigmaticum, Bashkortostan, Russia, early Roadian ; 4 Datheosaurus macrourus Lower Silesian Voivodeship, Poland, Gzhelian ; 5 Martensius bromackerensis, Thuringia, Germany, Sakmarian ; 6 Callibrachion gaudryi, Saône-et-Loire, France, Asselian ; 7 Euromycter rutenus and Ruthenosaurus russellorum, Aveyron, France, late Artinskian ; 8 Lalieudorhynchus gandi, Hérault, France, Wordian – early Capitanian ; 9 Alierasaurus ronchii, Nurra, Sardinia, Italy, Roadian ; 10 Eocasea martini, Greenwood County, Kansas, late Pennsylvanian ; 11 Angelosaurus romeri and Cotylorhynchus bransoni, Kingfisher County, Oklahoma, early Roadian ; 12 Cotylorhynchus bransoni, Blaine County, Oklahoma, early Roadian ; 13 Cotylorhynchus romeri, Logan County, Oklahoma, mid-late Kungurian ; 14 Cotylorhynchus romeri, Cleveland County, Oklahoma, mid-late Kungurian ; 15 Oromycter dolesorum and Arisierpeton simplex, Comanche County, Oklahoma, early Artinskian ; 16 Cotylorhynchus hancocki, Hardeman County, Texas, late Kungurian – early Roadian ; 17 Cotylorhynchus hancocki, Angelosaurus dolani, A. greeni, Caseoides sanangeloensis, and Caseopsis agilis, Knox County, Texas, late Kungurian – early Roadian ; 18 Casea broilii, Baylor County, Texas, mid-late Kungurian.

rdf:langString Cotylorhynchus romeri. Top : skull reconstruction in left lateral view, and medial and lateral views of mandible ; bottom : skull reconstruction in dorsal, ventral, posterior and anterior views.

rdf:langString Late Carboniferous - Middle Permian,

rdf:langString Distribution of caseid synapsids in late Paleozoic Pangea.jpg

rdf:langString Distribution of caseid synapsids in late Paleozoic Pangea detail.jpg

rdf:langString Cotylorhynchus skull 1.jpg

rdf:langString Cotylorhynchus skull 2.jpg

rdf:langString Fossil skeleton of Cotylorhynchus romeri

rdf:langString *Alierasaurus *Angelosaurus *Arisierpeton *Callibrachion *Casea *Caseoides *Caseopsis *Cotylorhynchus *Datheosaurus *Ennatosaurus *Eocasea *Euromycter *Lalieudorhynchus *Martensius *Oromycter *Phreatophasma *Ruthenosaurus *Trichasaurus

rdf:langString Genera

rdf:langString Caseidae

rdf:langString 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 (formely 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. 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.