不寻常的骨床揭示了在三叠纪末期灭绝之前,赤道潘盖亚的类动物和乌的脊椎动物社区
Ben T Kligman1, Robin L Whatley2, Jahandar Ramezani3
1Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013.
概括
亚利桑那州的一个罕见的化石遗址揭示了在特里亚斯纪末期灭绝之前的多样化的特里亚斯纪后期生态系统. 这一发现揭示了早期的乌和龙的进化和在潘盖亚的分散.
科学领域:
- 古生物学的古生物学
- 在平流图学上,平流图学是平流图学.
- 地质时间学 (Geochronology)
背景情况:
- 受到时间限制的微脊椎动物骨床对于理解大陆范围内的生物变化至关重要.
- 在末灭绝 (ETE) 之前的1200万年间,在全球非海洋环境中,这样的遗址很少见,这阻碍了动物变化分析的模式.
- 来自亚利桑那州的一组脊椎动物提供了对ETE前社区组成和生态学的独特见解.
研究的目的:
- 分析来自亚利桑那州的一组脊椎动物,以了解在特里亚斯纪末期灭绝之前的社区组成和生态.
- 为了提供精确的放射性同位素约会,为一个新的早期分离的类动物提供精确的放射性同位素约会,并完善乌贝起源的时间约束.
- 调查特有三叠纪脊椎动物血统的持久性及其与关键中生代种群的共存情况.
主要方法:
- 挖掘和分析的宏观和微脊椎动物骨床 (PFV 393) 保存在火山级流河道填充.
- 高精度的U-Pb石约会可以确定化石组合的精确放射性同位素年龄 (209.187 ± 0.083 Ma).
- 识别和描述已知和新种类的三维保存的骨元素,包括类动物和类动物.
主要成果:
- PFV 393骨床产生了多样化的古人类社区,包括hybodontiformes,actinopterygians,actinistians,metoposaurids,salientians,synapsids,lepidosaurs,testidinatans,trilophosaurids,Vancleavea,doswelliids,Revueltosaurus,loricatans,phytosaurs和pterosaurs等.
- 一种新的早期分离的龙,是欧洲以外的少数特里亚斯纪标本之一,被发现具有精确的放射性同位素测年.
- 泰斯图迪纳坦的材料表明,在诺里亚时代,陆地干甲在潘盖亚迅速分散,细化了乌外的起源.
结论:
- 亚利桑那州的化石遗址记录了一个当地古老社区,在ETE之前的环境变化中持续存在.
- 特有三世脊椎动物系与关键的三世后中生代群体 (如青,类动物,乌和类动物) 共存.
- 乌和类动物在潘盖亚中西部的到来可能与劳伦西亚向北漂移到更干旱的亚热带度相关.
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