The strata of the American Southwest, particularly the Chinle Formation and the Dockum Group, are critical to our understanding of faunal diversity and evolution in the Late Triassic. In recent decades, these strata have informed the evolution of close dinosaur relatives, which remain poorly sampled and enigmatic in their geographic distribution. Here, we describe and discuss a new non-dinosaurian dinosauromorph assemblage from the Los Esteros Member of the Santa Rosa Formation at the base of the Dockum Group in east-central New Mexico. This assemblage includes hindlimb fragments assignable to Silesauridae and Lagerpetidae. Much of the lagerpetid material, assignable to Dromomeron, is of unusually large size. Based on a dataset of complete lagerpetid femora, we estimate a total femoral length of 221.9 mm for one partial femur, making it the largest reported individual. We also provide biochronological support that at least a portion of the Los Esteros Member corresponds to the Otischalkian land vertebrate faunachron through the identification of non-Mystriosuchinae phytosaurs. Subsequently, we question the presence of a bifurcated lateral ridge on the squamosal of all phytosaurs currently assigned to Parasuchus. This is the first Otischalkian fauna identified from New Mexico, and it reveals lagerpetids achieved large body size earlier than previously recognized. Our identifications expand the geographic and temporal range of non-dinosaurian dinosauromorphs in the American Southwest. The material presented here, in conjunction with an increasing number of Dromomeron specimens, demonstrates that non-dinosauriform dinosauromorphs could match or exceed the body size of many coeval dinosaurs.

美国西南部的地层，特别是Chinle组和Dockum组，对于我们对三叠纪晚期动物群多样性和进化的理解至关重要。在最近的几十年中，这些地层为近亲恐龙的进化提供了信息，而近亲恐龙的采样在地理分布上仍然很差且难以捉摸。在这里，我们描述和讨论一种新的非恐龙恐龙恐龙组合，它来自新墨西哥州中东部Dockum集团基地的Santa Rosa组的Los Esteros成员。该组合包括可分配给唇形科和唇形科的后肢片段。可分配给Dromomeron的大部分lagerpetid材料，大小异常大。根据完整的紫ger股骨的数据集，我们估计一部分股骨的总股骨长度为221.9 mm，使其成为报告的最大个体。我们还提供了生物年代学上的支持，即通过鉴定非Mystriosuchinae的植物蜥蜴，Los Esteros成员的至少一部分对应于Otischalkian陆地脊椎动物动物群。随后，我们质疑分叉横向棱线的当前分配给所有植龙目的鳞存在Parasuchus。这是从新墨西哥州发现的第一个奥氏体动物群，它揭示了比以前认识到的更大体型的储藏物。我们的鉴定扩展了美国西南部非恐龙龙类的地理和时间范围。此处介绍的材料与越来越多的Dromomeron标本一起证明，非恐龙龙形恐龙可以与许多中世纪的恐龙匹配或超过它们的体型。