University of Greifswald, Institute of Geography and Geology, Palaeontology and Historical, Greifswald, Germany.
University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary Biology, Greifswald, Germany.
Elife. 2022 Dec 20;11:e82190. doi: 10.7554/eLife.82190.
Macronaria, a group of mostly colossal sauropod dinosaurs, comprised the largest terrestrial vertebrates of Earth's history. However, some of the smallest sauropods belong to this group as well. The Late Jurassic macronarian island dwarf is one of the most peculiar and best-studied sauropods worldwide. So far, the braincase material of this taxon from Germany pended greater attention. With the aid of micro-computed tomography (microCT), we report on the neuroanatomy of the nearly complete braincase of an adult individual, as well as the inner ears (endosseous labyrinths) of one other adult and several juveniles (the latter also containing novel vascular cavities). The presence of large and morphologically adult inner ears in juvenile material suggests precociality. Our findings add to the diversity of neurovascular anatomy in sauropod braincases and buttress the perception of sauropods as fast-growing and autonomous giants with manifold facets of reproductive and social behaviour. This suggests that - apart from sheer size - little separated from its large-bodied relatives.
马氏龙，一类巨型蜥脚类恐龙，包含了地球历史上最大的陆生脊椎动物。然而，该类群也有一些最小的蜥脚类恐龙。晚侏罗世的马氏龙岛矮人是世界上最奇特和研究最充分的蜥脚类恐龙之一。到目前为止，来自德国的该分类单元的脑壳材料引起了更多关注。借助微计算机断层扫描（microCT），我们报告了一个成年个体近乎完整的脑壳以及另外一个成年个体和几个幼年个体（后者还包含新颖的血管腔）的内耳（内骨骼迷路）的神经解剖结构。在幼年个体中发现的大型且形态上成熟的内耳表明早熟性。我们的发现增加了蜥脚类恐龙脑壳的神经血管解剖结构的多样性，并支持了蜥脚类恐龙是快速生长和自主的巨型动物的观点，具有多种生殖和社会行为的观点。这表明，除了体型庞大之外，与它的大型亲属没有什么不同。
