Azuma Yoichi, Xu Xing, Shibata Masateru, Kawabe Soichiro, Miyata Kazunori, Imai Takuya
Institute of Dinosaur Research, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji, Fukui, 910-1195 Japan.
Fukui Prefectural Dinosaur Museum, 51-11 Terao, Muroko, Katsuyama, Fukui 911-8601, Japan.
Sci Rep. 2016 Feb 23;6:20478. doi: 10.1038/srep20478.
Our understanding of coelurosaurian evolution, particularly of bird origins, has been greatly improved, mainly due to numerous recently discovered fossils worldwide. Nearly all these discoveries are referable to the previously known coelurosaurian subgroups. Here, we report a new theropod, Fukuivenator paradoxus, gen. et sp. nov., based on a nearly complete specimen from the Lower Cretaceous Kitadani Formation of the Tetori Group, Fukui, Japan. While Fukuivenator possesses a large number of morphological features unknown in any other theropod, it has a combination of primitive and derived features seen in different theropod subgroups, notably dromaeosaurid dinosaurs. Computed-tomography data indicate that Fukuivenator possesses inner ears whose morphology is intermediate between those of birds and non-avian dinosaurs. Our phylogenetic analysis recovers Fukuivenator as a basally branching maniraptoran theropod, yet is unable to refer it to any known coelurosaurian subgroups. The discovery of Fukuivenator considerably increases the morphological disparity of coelurosaurian dinosaurs and highlights the high levels of homoplasy in coelurosaurian evolution.
我们对虚骨龙类进化，尤其是鸟类起源的理解有了极大的提升，这主要归功于全球范围内近期发现的大量化石。几乎所有这些发现都可归入此前已知的虚骨龙类亚群。在此，我们报道一种新的兽脚亚目恐龙——奇异福井猎龙（Fukuivenator paradoxus），属种为新属新种，其化石基于一件近乎完整的标本，该标本采自日本福井县手取群木谷田组的下白垩统。尽管福井猎龙拥有许多其他兽脚亚目恐龙所没有的形态特征，但它同时具备了不同兽脚亚目恐龙亚群中原始特征与衍生特征的组合，特别是驰龙科恐龙。计算机断层扫描数据显示，福井猎龙内耳的形态介于鸟类和非鸟类恐龙之间。我们的系统发育分析将福井猎龙恢复为基础分支的手盗龙类兽脚亚目恐龙，但无法将其归入任何已知的虚骨龙类亚群。福井猎龙的发现极大地增加了虚骨龙类恐龙的形态差异，并凸显了虚骨龙类进化过程中高度的同塑性。
