size, first in the clade Stenaulorhynchinae and then in the clade Hyperodapedontinae. The stratigraphically lowest known species of rhynchosaur is Noteosuchus colletti, currently found in Lower Triassic strata in South Africa. When it was first discovered, Noteosuchus was thought to be an “eosuchian” (Watson 1917) and was later believed to be an ancestor to multiple different species, including phytosaurs (Broom 1925). It was not until 1928 that Franz Nopcsa first identified it as a rhynchosaur, which was later affirmed in 1976 by Robert Carroll. Still, this species tends to be problematic for phylogenetic trees since it lacks a cranium. Due to the distinct qualities of Rhynchosauria as a whole, namely their edentulous premaxillae, unique maxillary dentition, and broad heads, we expect to see continuity within the group Rhynchosauria and discontinuity from the other groups within Archosauromorpha. 4. Proterosuchidae, Erythrosuchidae, and Euparkeriidae Proterosuchidae, Erythrosuchidae, and Euparkeriidae are families within the group Archosauriformes. There have been 30 species placed in Proterosuchia (Ezcurra et al. 2013). Although proterosuchids and erythrosuchids are near each other cladistically (along with Euparkeriidae) and have previously been placed within Proterosuchia, they are very different morphologically (Ezcurra et al. 2013). Proterosuchids are the stratigraphically first appearing archosauriforms, with the species Archosaurus rossicus found in the uppermost Permian deposits of Russia. It is only known from one specimen, which includes fragmentary bones from the skull and cervical vertebrae. Although common in Lower Triassic layers, it has been claimed that proterosuchids were found in Middle Triassic strata, but these examples are questionable (Ezcurra et al. 2013). It may be that these specimens are not even from proterosuchids at all. Proterosuchids from the Lower Triassic include Proterosuchus fergusi, from the Induan stage of South Africa, and Chasmatosaurus yuani, from the Induan stage of China. Proterosuchids are characterized by an overhanging premaxilla, sprawling gait, and elongated low skulls. It has been proposed that they had palatal and pterygoidal teeth, however, most fossil samples are not well preserved enough to tell. The largest members of the group could reach up to 4 meters long, and the longest skull length recorded was 47.7 centimeters. They were believed to be semi-terrestrial, living mostly on land but taking to the water when needed, possibly to feed. Their pelvic girdle allowed for powerful locomotion forward, and the structure of the zygapophyses allowed for lateral flexure of the tail (Ezcurra et al. 2013). According to Ezcurra et al. (2013), they were the most abundant predator found in the Lower Triassic of the Karoo Basin. Erythrosuchids were large predators (4.75-5 meters long) that had less of a sprawling gait than proterosuchids. They are thought to have been the top carnivores of their ecosystems (Ezcurra et al. 2013). Although most erythrosuchids lacked palatal teeth (Butler et al. 2019b; Ezcurra et al. 2018), erythrosuchids possessed massive skulls in proportion to their bodies with sharp teeth, resulting in erythrosuchids sometimes being described as “prehistoric bulldogs.” It has been suggested that the disproportionately large heads of erythrosuchids and large theropods indicate that enormous heads are prerequisites for hypercarnivory in archosauriforms, but Bestwick et al. (2022) concluded that phylogeny, rather than factors like diet, largely determined the enormous skull size in the two groups. It has been debated whether or not erythrosuchids were terrestrial or semi-aquatic based on their enormous skull size. The consensus is that they probably lived in marshy, swamp environments (Ezcurra et al. 2013). Fossil samples have been found in the uppermost Lower Triassic and Middle Triassic (up to the Ladinian) layers. The histology in the limb bones of erythrosuchids and proterosuchids shows that there was rapid growth in their bodies before they reached sexual maturity (Ezcurra et al. 2013). Euparkeria is another non-archosaurian archosauriform, but it is a much smaller animal than the proterosuchids or erythrosuchids, reaching about 1 m in length. It and its closest relatives (Osmolskina and Halazhaisuchus) form the family Euparkeriidae, although there are no definite synapomorphies that define this family, making it possible that this is an artificial grouping (Borsuk−Białynicka and Evans 2009). Dilkes and Sues (2009) concluded that Euparkeria capensis was stem-ward of Erythrosuchus africanus, whereas Ezcurra et al. (2010) recognized it as more crownward. Ezcurra (2016) recovered Euparkeria as the sister taxon to the group that includes proterochampsians and archosaurs. It has been suggested that euparkeriids might be bipedal, but Sookias and Butler (2013) argue that the head would have been too large for the animal to stand on its hind legs. Based on the size of the scerlotic ring in Euparkeria, Schmitz and Motani (2011) concluded that it may have been nocturnal. Euparkeriids were carnivorous, and based on their size, would have hunted smaller prey. Fossil samples for Euparkeria are very sparse, limited to only the lower portion of the Middle Triassic in South Africa. Our prediction in conducting baraminology research is that we will find discontinuity between these three groups. While there are similarities between them morphologically, our suspicion is that there will be distinct created kinds. 5. Proterochampsia The proterochampsians are a group of semi-aquatic archosauriforms found in Middle to Upper Triassic rocks of Brazil and Argentina. Superficially similar to crocodylians, proterochampsians have elongated snouts with the nostrils on the tip, semi-round orbits, ornamented armor, and conical, curved, thecodont teeth (Trotteyn et al. 2013). However, proterochampsians had other features unlike crocodylians, including longer legs and a ridge that runs underneath the eyes. Although sometimes included within the group Archosauria (Parrish 1993), Proterochampsia is most commonly recovered within non-archosaurian Archosauriformes (Ezcurra 2016; Nesbitt 2011). Rhadinosuchus gracilis was the first proterochampsian to be discovered, and throughout the mid-1900s, more proterochampsian fossils were found in the Santa Maria, Chañares, and Ischigualasto Formations (Trotteyn et al. 2013). Proterochampsia was named by Bonaparte in 1971 to include Proterochampsidae and Cerritosauridae (although now Cerritosaurus is just seen as a member of Proterochampsidae). According to Ezcurra (2016), Proterochampsidae is one of the two groups within Proterochampsia, with the second being Doswelliidae, although this clade is not considered to be a part of Proterochampsia by all researchers (e.g., Benton and Clark 1988). The Doswelliidae are also crocodylian-like archosauriforms, but often have flatter, longer snouts and longer bodies than other proterochampsids. While the Proterochampsidae are found mainly in South America, a few doswelliid species have been found in Europe and in North America. Doswelliids have morphological similarities to proterochampsids, such as the conical thecodont teeth, ornamented armor, and long snouts (Weems 1980). Vancleavea campi is a peculiar short-snouted, heavily armored, semi-aquatic archosauromorph from the Chinle Formation (Nesbitt et al. 2009) that has been considered as a possible doswelliid (Ezcurra 2016). MCLAIN, CLAUSEN, PEREZ, BEEBE, AND AHTEN Archosauromorph Baraminology 2023 ICC 490
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