Winkler Daniela E, Tschopp Emanuel, Saleiro André, Wiesinger Ria, Kaiser Thomas M
Zoological Institute, Kiel University, Kiel, Germany.
Centre for Taxonomy and Morphology, Leibniz Institute for the Analysis of Biodiversity Change, Museum of Nature, Hamburg, Germany.
Nat Ecol Evol. 2025 Jul 18. doi: 10.1038/s41559-025-02794-5.
Most faunas from the Mesozoic era were dominated by sauropod dinosaurs, the largest terrestrial animals to ever exist. These megaherbivores were remarkably diverse and widely distributed. Here we study three Late Jurassic faunas from the USA, Portugal and Tanzania, each approximately 150 million years old, which are known for their extreme sauropod diversity. Whereas general taxonomic composition was similar in these three faunas, the major clades differed in relative abundance. Moreover, their depositional strata record distinct climatic regimes. Using dental microwear texture analysis, we investigated the impact of these climate regimes and the resulting food availability on the different sauropod taxa. Wear patterns in camarasaurid macronarians show minimal variation across different climate regimes, supporting previous studies suggesting that these animals migrated to follow their preferred climate niche and food source. North American camarasaurids show similar wear patterns to those of Portuguese turiasaurs, another broad-crowned taxon, which did not exist in the Jurassic of North America. By contrast, where camarasaurids and turiasaurs co-occurred in Portugal, their microwear patterns are distinct, suggesting niche differentiation to avoid ecological competition between these two clades. Flagellicaudatan diplodocoids display highly variable wear patterns, indicating limited migration (and therefore seasonal variation in diet), which aligns with observed biogeography patterns in the USA. Early-branching titanosauriforms show highly distinct wear patterns between different climate regimes, which can probably be attributed to different abrasive loads in the respective habitats. Our results demonstrate that dental microwear texture analysis not only records dietary preferences but also reveals behaviour such as competition and migration related to dietary niches in past ecosystems.
中生代的大多数动物群都由蜥脚类恐龙主导，它们是有史以来最大的陆地动物。这些巨型食草动物种类极为多样，分布广泛。在此，我们研究了来自美国、葡萄牙和坦桑尼亚的三个晚侏罗世动物群，它们距今约1.5亿年，以其极端的蜥脚类恐龙多样性而闻名。尽管这三个动物群的总体分类组成相似，但主要类群在相对丰度上有所不同。此外，它们的沉积地层记录了不同的气候状况。利用牙齿微磨损纹理分析，我们研究了这些气候状况以及由此产生的食物可获得性对不同蜥脚类分类群的影响。圆顶龙类巨龙的磨损模式在不同气候状况下变化极小，这支持了先前的研究，即这些动物会迁徙以追寻它们偏好的气候生态位和食物来源。北美圆顶龙类的磨损模式与葡萄牙梁龙类相似，后者是另一个宽冠类群，在北美侏罗纪并不存在。相比之下，在葡萄牙圆顶龙类和梁龙类共存的地方，它们的微磨损模式截然不同，这表明存在生态位分化以避免这两个类群之间的生态竞争。鞭尾类双梁龙显示出高度可变的磨损模式，表明其迁徙受限（因此饮食存在季节性变化），这与在美国观察到的生物地理学模式相符。早期分支的泰坦龙形类在不同气候状况下显示出高度不同的磨损模式，这可能归因于各自栖息地不同的磨蚀负荷。我们的结果表明，牙齿微磨损纹理分析不仅记录了饮食偏好，还揭示了过去生态系统中与饮食生态位相关的竞争和迁徙等行为。
