Dinosaurs arose in the Late Triassic and diversified during the subsequent periods of the Mesozoic Era. The oldest unequivocal dinosaurs come from Carnian deposits of Brazil, Argentina, India, and Zimbabwe, with sauropodomorphs representing the bulk of this record. Saturnalia tupiniquim was described from Brazilian strata in 1999 as the first Carnian member of that group. Although several new species and specimens of coeval sauropodomorphs have been described in recent years, no new material has been formally assigned to that species. In this contribution, we describe an association of at least three partially preserved individuals of S. tupiniquim (UFSM 11660), which was excavated from the S. tupiniquim type-locality (Late Triassic of the Santa Maria Formation) and preserves cranial and postcranial elements, including the first rostrum known for the species. Assigned to S. tupiniquim according to several lines of evidence, the new specimen has a proportionally short rostrum, compared to that of coeval sauropodomorphs, providing evidence for a reduced skull in S. tupiniquim. In addition, we investigated the intraspecific variation in S. tupiniquim, highlighting the need to understand the morphological limits of such variations among the earliest dinosaurs, in order to properly explore their alpha diversity.

中文翻译：

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农神节（恐龙：蜥脚形目）的新标本：对种内变异、喙部解剖结构和颅骨大小的见解


恐龙起源于晚三叠世，并在中生代的后续时期多样化。最古老的明确恐龙来自巴西、阿根廷、印度和津巴布韦的 Carnian 矿床，其中蜥脚形目代表了这一记录的大部分。1999 年，来自巴西地层的农神节 tupiniquim 被描述为该组的第一个 Carnian 成员。尽管近年来已经描述了几个新物种和同时代的蜥脚形类动物标本，但尚未正式为该物种分配新材料。在这篇文章中，我们描述了至少三个部分保存的 S. tupiniquim （UFSM 11660） 个体的关联，它是从 S. tupiniquim 类型产地（圣玛丽亚组晚三叠世）挖掘出来的，并保留了颅骨和颅后元素，包括该物种已知的第一个讲台。根据几条证据线分配给 S. tupiniquim，与同时代的蜥脚形类相比，新标本的喙成比例地短，为 S. tupiniquim 的头骨缩小提供了证据。此外，我们还研究了 S. tupiniquim 的种内变异，强调需要了解最早恐龙中此类变异的形态极限，以便正确探索它们的 alpha 多样性。