Recent excavations from the “Paléontologie A16” project brought to light thousands of dinosaur footprints and numerous turtle remains from the Late Jurassic of Porrentruy (Swiss Jura Mountains). While most fossil turtles (Thalassochelydia) were found in marly layers that were deposited in a coastal marine paleoenvironment, the dinosaur (theropod and sauropod) tracks were found in laminites that were deposited in a tidal flat environment. Despite extensive exploration, very few body fossils were found in these dinosaur track-bearing laminites. On one occasion, a sub-complete turtle shell (Plesiochelys bigleri) was discovered within the laminites, embedded just beneath an important sauropod track level. The state of preservation of this specimen suggests that the turtle died on the tidal flat and was quickly buried. This is the first evidence that these turtles occasionally visited tidal flat paleoenvironments. Moreover, the particular configuration of the fossil turtle suggests that the shell was possibly trodden on by a large sauropod dinosaur.

中文翻译：

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在蜥脚类动物的脚下：一只来自瑞士侏罗纪晚期的被践踏的沿海海龟？

“PaléontologieA16”项目的近期发掘使成千上万的恐龙脚印和来自波伦特鲁伊晚侏罗纪（瑞士侏罗山）的大量海龟遗骸被发现。虽然大多数化石海龟（Thalassochelydia）是在沿海海洋古环境中沉积的海相层中发现的，但恐龙（兽脚类和蜥脚类动物）的踪迹是在潮汐平坦环境中沉积的层状岩中发现的。尽管进行了广泛的探索，但在这些带有恐龙轨迹的薄片中却很少发现人体化石。有一次，在薄片体内发现了一个不完全的海龟壳（Plesiochelys bigleri），嵌在重要的蜥脚类动物的轨道下方。该标本的保存状态表明，这只乌龟死于潮滩并被迅速埋葬。这是这些海龟偶尔造访潮滩古环境的第一个证据。而且，化石龟的特殊构造表明其壳可能被大型蜥脚类恐龙踩踏了。