Triassic rocks around the world preserve the remains of fascinating reptile groups like phytosaurs, rhynchosaurs, and tanystropheids that appear in the stratigraphic record as suddenly as they disappear. These animals—along with the more famous archosaurs (e.g., dinosaurs, pterosaurs, and crocodilians)—belong to a large taxonomic group called Archosauromorpha. Although there have been multiple statistical baraminological analyses conducted on various archosaurian taxa, non-archosaur archosauromorphs remain largely unstudied from a creationist perspective. In order to understand the baraminic relationships of these creatures known exclusively from the fossil record, we applied statistical baraminological methods to a recent morphological dataset. We analyzed the dataset with baraminic distance correlation, multidimensional scaling, partition around medoids, and fuzzy analysis via BARCLAY. Recognizing that the dataset contained many disparate taxonomic groups, we reanalyzed the results in subset analyses. As a result of this study, we find multiple non-archosaur archosauromorph holobaramins including: Rhynchosauria, Allokotosauria, Tanystropheidae + Dinocephalosauridae, Proterosuchidae, Erythrosuchidae, Proterochampsidae, Erpetosuchidae, and Phytosauria. These results are consistent with our expectations that 1) there would be different created kinds of non-archosaur archosauromorphs, and 2) statistical baraminological methods would result in groups traditionally recognized in taxonomies and near the level of family. ABSTRACT INTRODUCTION Traditionally, many of the animals we are analyzing in this article were thrown into a wastebasket group called “Thecodontia” (Owen 1859) named because their teeth were set in sockets (as is the case with crocodilians, dinosaurs, and mammals). The thecodonts were thought to form an ancestral stock out of which came more “derived” taxa such as dinosaurs, crocodilians, pterosaurs, and birds. It was only later with more detailed studies that relationships between the various “thecodont” taxa were teased out. By 1956, Alfred Romer in his classic The Osteology of Reptiles recognized various subtaxa within Thecodontia including Proterosuchia (Proterosuchidae and Erythrosuchidae), Pseudosuchia (some modern non-crocodilian pseudosuchians, Euparkeriidae, and Scleromochlidae), and Parasuchia (Phytosauria). He also did not recognize some groups currently considered archosauromorphs to be close relatives of archosaurs as evidenced by his placement of rhynchosaurs within Rhynchocephalia (tuataras and their extinct relatives) and protorosaurs (including tanystropheids) within Euryapsida (an old grouping for sauropterygians and their supposed relatives). Later, Jacques Gauthier (1986) wrote, “From a phylogenetic perspective, “Thecodontia” and Archosauria are diagnosed by the same synapomorphies. Thus, these taxa are redundant…” (p. 2). The term Archosauromorpha was coined by German paleontologist Friedrich von Huene in 1946. With the advent of cladistics, the name Archosauromorpha was applied to Archosauria and those taxa on the line to it and not on the line to the lepidosaurs (lizards, snakes, and sphenodontians). There have been multiple definitions for the clade Archosauromorpha. Michel Laurin (1991) defined it as the clade containing the most recent common ancestor of Prolacerta, Trilophosaurus, Hyperodapedon and all of its descendants, which is a node-based definition. David Dilkes (1998) instead defined it as, “Protorosaurus and all other saurians that are related more closely to Protorosaurus than to Lepidosauria” (p. 528). Dilkes intended his definition to replace Laurin (1991) because Laurin’s definition would exclude Protorosaurus, Drepanosauridae, and Tanystropheidae. Additionally, this newer definition is stem-based, which matches the stem-based definition for Lepidosauromorpha (Gauthier et al. 1988). Laurin’s more exclusive form of Archosauromorpha corresponds closely to the group Crocopoda named by Ezcurra (2016) to include all archosauriforms, rhynchosaurs, and allokotosaurs to the exclusion of tanystropheids. The first definitive archosauromorphs in the fossil record are found in the Middle-Upper Permian, with Ezcurra et al. (2014) only recognizing four definite species: Protorosaurus speneri, Archosaurus rossicus, Eorasaurus olsoni, and Aenigmastropheus parringtoni. Additional Permian archosauromorph remains include a distal humerus reminiscent of tanystropheids from Brazil (Martinelli et al. 2017). However, in the overlying Triassic layers, archosauromorphs are incredibly common and make up the majority of terrestrial tetrapods by the Upper Triassic. Archosauromorphs are characterized by several features including a premaxilla extending dorsally to the external naris, excluding the maxilla from the narial margin (Laurin 1991), and a lack of an entepicondylar foramen on the humerus (Ezcurra 2016). The major archosauromorph taxa are shown on a cladogram in Figure 1. Excluding the “protorosaurs”, all archosauromorphs are in the group Crocopoda. Most crocopods are also in the more exclusive group Archosauriformes (to the exclusion of rhynchosaurs, allokotosaurs, and a few others). Archosauriforms–including Archosauria and a few smaller groups (e.g., proterosuchids, erythrosuchids, proteroMatthew A. McLain, Caroline Clausen, Thai Perez, Katherine Beebe, and Alia Ahten. The Master’s University, Department of Biological and Physical Sciences, 21726 Placerita Canyon Road, Santa Clarita, California, 91321 © Cedarville University International Conference on Creationism. The views expressed in this publication are those of the author(s) and do not necessarily represent those of Cedarville University. 9th 2023 McLain M.A., C. Clausen, T. Perez, K. Beebe, and A. Ahten. 2023. A Preliminary analysis of archosauromorph baraminology. In J.H. Whitmore (editor), Proceedings of the Ninth International Conference on Creationism, pp. 487-539. Cedarville, Ohio: Cedarville University International Conference on Creationism. A PRELIMINARY ANALYSIS OF ARCHOSAUROMORPH BARAMINOLOGY KEYWORDS Baraminology, Archosauromorpha, Archosauria, created kinds, Triassic, Rhynchosauria, Proterochampsia, Phytosauria
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