美国史密森学会国家自然历史博物馆Ben T. Kligman团队报道不寻常的骨床揭示了三叠纪末灭绝前赤道泛大陆的翼龙和海龟脊椎动物群落。这一研究成果于2025年7月7日发表在《美国科学院院刊》杂志上。

具有精确时代限定的微体脊椎动物骨层是理解大陆尺度生物演变的强有力工具。然而，在晚三叠世生物大灭绝事件（ETE；约201.5 Ma）之前的1200万年（Ma）间，此类非海相遗址在全球范围内极为稀少，掩盖了该时段内的动物群变化模式。美国亚利桑那州的一个脊椎动物化石组合，为理解ETE之前的群落组成和生态提供了独特视角。

PFV 393 是一个包含宏体与微体脊椎动物的骨层，保存在一个火山碎屑质河道充填沉积中，其锆石高精度U-Pb年龄为209.187 ± 0.083 Ma。该化石组合包含多种已知及新分类单元的三维保存、结构精细且微小的骨骼元素，记录了一个包含以下类群的局部古生物群落：弓鲛目、辐鳍鱼类、腔棘鱼类、笠头螈科、无尾目类（蛙类）、合弓纲、鳞龙形类、龟鳖类、三棱龙科、Vancleavea、道斯威尔龙科、Revueltosaurus、甲龙形类、植龙目以及翼龙目。其中新发现的早期分化翼龙，是欧洲以外发现的少数三叠纪翼龙之一，也是唯一一个拥有精确同位素年龄记录的翼龙。龟鳖类化石材料揭示了陆生干龟类在诺利期快速扩散至盘古超大陆的现象，并精确限定了龟壳起源的时间框架。

该遗址中存在的三叠纪特有脊椎动物谱系，突显了它们在ETE之前漫长的环境变化阶段中，在一个湿润的河流古群落中持续存在。这些谱系与蛙类、鳞龙类、龟类以及翼龙共存——而后者皆是三叠纪之后中生代群落的关键组成部分。因此，龟类和翼龙出现在盘古大陆中西部，可能是由劳伦大陆（北美克拉通）从湿润的赤道环境向北漂移至更干旱的亚热带纬度区域所驱动。

附：英文原文

Title: Unusual bone bed reveals a vertebrate community with pterosaurs and turtles in equatorial Pangaea before the end-Triassic extinction

Author: Kligman, Ben T., Whatley, Robin L., Ramezani, Jahandar, Marsh, Adam D., Lyson, Tyler R., Fitch, Adam J., Parker, William G., Behrensmeyer, Anna K.

Issue&Volume: 2025-7-7

Abstract: Temporally constrained microvertebrate bone beds are powerful tools for understanding continent-scale biotic change. Such sites are rare globally in nonmarine settings during the 12 million years (Ma) preceding the end-Triassic extinction (ETE; ~201.5 Ma), obscuring patterns of faunal change across this interval. A vertebrate assemblage from Arizona, USA, provides unique insights into community composition and ecology prior to the ETE. PFV 393 is a macro- and microvertebrate bone bed preserved in a volcaniclastic fluvial channel-fill with a high-precision U-Pb zircon age of 209.187 ± 0.083 Ma. The fossil assemblage consists of three-dimensionally preserved, delicate, and small skeletal elements of known and new taxa that document a local paleocommunity including hybodontiformes, actinopterygians, actinistians, metoposaurids, salientians, synapsids, lepidosaurs, testudinatans, trilophosaurids, Vancleavea, doswelliids, Revueltosaurus, loricatans, phytosaurs, and pterosaurs. The new early-diverging pterosaur is one of the few Triassic pterosaurs found outside of Europe and the only one with a documented precise radioisotopic age. The testudinatan material shows the rapid dispersal of terrestrial stem-turtles across the Pangaean supercontinent in the Norian and refines temporal constraints on the origin of the turtle shell. The presence of vertebrate lineages endemic to the Triassic highlights their persistence in a mesic, fluvial paleocommunity through a prolonged phase of environmental change preceding the ETE. These lineages coexisted with frogs, lepidosaurs, turtles, and pterosaurs- all key elements of post–Triassic Mesozoic communities. The arrival of turtles and pterosaurs in west-central Pangaea therefore may have been driven by the northward drift of Laurentia from humid equatorial conditions into more arid subtropical latitudes.

DOI: 10.1073/pnas.2505513122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2505513122