Metoposaurids are a widespread and ubiquitous constituent of Late Triassic non-marine paleoenvironments. In North America, this group is practically the only large-bodied temnospondyl clade, and is particularly well documented from the American southwest and south-central regions (Arizona, New Mexico, Texas). However, metoposaurids are poorly documented from eastern North America, with fragmentary, doubtfully diagnostic historical material such as “Dictyocephalus elegans” Leidy, 1856 and “Eupelor durus” Cope, 1866. The Zions View (early Norian?) locality in Pennsylvania preserves more-complete material, which previous workers noted as belonging to “Buettneria perfecta” Case, 1922 (=Anaschisma browni Branson, 1905). However, the material has never been described in a fashion that characterizes the anatomy or that justifies the taxonomic assignment, yet it would represent the most complete material in eastern North America and a substantial expansion of this taxon's geographic range. Here we redescribe the Zions View metoposaurid material in detail, differentiating it from Calamops paludosus Sinclair, 1917, the only other Late Triassic temnospondyl from the eastern seaboard, and demonstrating confident affinities with A. browni. Our study is the first to properly justify the taxonomic referral, underscoring the broader importance of proper documentation of voucher specimens, especially for potential geographic outliers. Anaschisma browni is thus the most widely dispersed metoposaurid. Its easternmost documentation underscores the importance of the undersampled and understudied metoposaurid record on the eastern seaboard for understanding the development of a metoposaurid zone of exclusivity in North America and demonstrates the need for further exploration to refine conceptualizations of Late Triassic tetrapod evolution.

中文翻译：

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来自宾夕法尼亚州新牛津组的甲龙类 Anaschisma browni 的描述

甲龙类是晚三叠世非海洋古环境中广泛而普遍的组成部分。在北美，这个群体实际上是唯一的大型 temnospondyl 进化枝，在美国西南部和中南部地区（亚利桑那州、新墨西哥州、德克萨斯州）的记录尤为充分。然而，北美东部的甲龙科记录很少，只有零碎的、可疑的诊断历史材料，例如“线虫” 莱迪，1856 年和“Eupelor durus” Cope，1866 年。宾夕法尼亚州的 Zions View（早期的诺里安人？）地区保存了更完整的材料，以前的工人指出这些材料属于“无花果” 案例，1922 年（=无花果褐斑病布兰森，1905）。然而，该材料从未以一种描述解剖学特征或证明分类学分配合理的方式描述，但它将代表北美东部最完整的材料，并大大扩展了该分类单元的地理范围。在这里，我们详细重新描述了 Zions View 甲龙材料，将其与菖蒲辛克莱，1917 年，东海岸唯一的其他晚三叠世 temnospondyl，并表现出与一种.布朗尼. 我们的研究是第一个正确证明分类学推荐合理性的研究，强调了适当记录凭证标本的更广泛的重要性，特别是对于潜在的地理异常值。无花果褐斑病因此是分布最广的甲龙类。其最东端的文件强调了在东部沿海地区采样不足和研究不足的甲龙类记录对于了解北美排他性甲龙区发展的重要性，并表明需要进一步探索以完善晚三叠世四足动物进化的概念。