Abstract Crocodylomorpha is a clade that has its origins during the Late Triassic and attained a global distribution early in their radiation. In this context, although limited to few geological units, the South American record has been relevant in the understanding of the origins of the clade. Additionally analyzing the South American crocodylomorph record and comparing it with the one in the rest of Pangea is relevant as, in recent years, provincialism has been proposed for different faunal assemblages. In this contribution we review the crocodylomorph Triassic record in South America by analyzing three units that have yielded fossils of the clade: the Santa Maria Supersequence in Brazil; and, the Ischigualasto and Los Colorados formations in Argentina. Our review does not support previous assignments of the taxon Barberenasuchus from the Santa Maria Supersequence as a non-crocodyliform crocodylomorph, as it displays traits that are absent in all known crocodylomorphs and are present in other earlier branching archosaurs. On the other hand, the Argentinian stratigraphic units remain as the only ones that have crocodylomorphs in the subcontinent. Here we report for the first time the occurrence of “large-bodied” crocodylomorphs in the Ischigualasto Formation, represented by a new yet undescribed taxon. The Los Colorados Formation has a diverse crocodylomorph record being represented by a non-crocodyliform crocodylomorph (Psedhesperosuchus) and two crocodyliforms (Hemiprotosuchus and Coloradisuchus). Here we present a putative new non-crocodyliform crocodylomorph taxon from Los Colorados Formation. When compared with other crocodylomorph bearing formations around Pangea, the Ischigualasto Formation bears similarities with the crocodylomorphs assemblages of North America due to the presence of early branching crocodylomorphs (Trialestes) including “large-bodied” taxa. The Los Colorados Formation reveals a transitional composition corresponding to Norian and Early Jurassic assemblages of Pangea, as it shares the presence of basal crocodyliforms (i.e., protosuchids) typical of Early Jurassic units (e.g., Upper Elliot) and basal non-crocodyliform crocodylomorphs, widely present in Norian assemblages.

中文翻译：

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南美鳄形目（古龙目；鳄形目）：该大陆早期化石记录的回顾及其与理解进化枝起源的相关性

摘要 Crocodylomorpha 是一个起源于晚三叠世并在其辐射早期达到全球分布的进化枝。在这种情况下，虽然仅限于少数地质单元，但南美洲的记录与了解该进化枝的起源有关。此外，分析南美鳄形记录并将其与泛大陆其他地区的记录进行比较是相关的，因为近年来，不同动物群的地方性已被提出。在这篇文章中，我们通过分析产生该进化枝化石的三个单元来回顾南美洲的鳄鱼形三叠纪记录：巴西的圣玛丽亚超序列；以及阿根廷的 Ischigualasto 和 Los Colorados 编队。我们的评论不支持先前将来自圣玛丽亚超序列的 Barberenasuchus 分类单元指定为非鳄鱼形鳄鱼，因为它显示了所有已知鳄鱼形中不存在的特征，并且存在于其他早期分支的主龙类中。另一方面，阿根廷地层单位仍然是次大陆唯一具有鳄鱼形态的地层单位。在这里，我们首次报告了在 Ischigualasto 组中出现的“大型”鳄鱼形，以一种新的尚未描述的分类群为代表。Los Colorados Formation 具有多样化的鳄鱼形记录，以非鳄鱼形鳄鱼形 (Psedhesperosuchus) 和两种鳄鱼形 (Hemiprotosuchus 和 Coloradisuchus) 为代表。在这里，我们介绍了一种来自 Los Colorados Formation 的推定的新非鳄鱼形鳄鱼形分类群。与 Pangea 周围的其他鳄鱼形构造相比，Ischigualasto 组与北美的鳄鱼形组合具有相似之处，因为存在包括“大型”分类群在内的早期分支鳄鱼形 (Trialestes)。Los Colorados 地层揭示了与 Pangea 的 Norian 和早侏罗世组合相对应的过渡组成，因为它共享存在早侏罗纪单位（例如，Upper Elliot）和基础非鳄鱼形鳄鱼典型的基底鳄鱼（即原鳄），广泛分布存在于 Norian 组合中。由于存在包括“大型”类群在内的早期分枝鳄鱼（Trialestes），Ischigualasto 组与北美的鳄鱼组合具有相似性。Los Colorados 地层揭示了与 Pangea 的 Norian 和早侏罗世组合相对应的过渡组成，因为它共享存在早侏罗纪单位（例如，Upper Elliot）和基础非鳄鱼形鳄鱼典型的基底鳄鱼（即原鳄），广泛分布存在于 Norian 组合中。由于存在包括“大型”类群在内的早期分枝鳄鱼（Trialestes），Ischigualasto 组与北美的鳄鱼组合具有相似性。Los Colorados 地层揭示了与 Pangea 的 Norian 和早侏罗世组合相对应的过渡组成，因为它共享存在早侏罗纪单位（例如，Upper Elliot）和基础非鳄鱼形鳄鱼典型的基底鳄鱼（即原鳄），广泛分布存在于 Norian 组合中。