| 新墨西哥州發現的新型肉食性恐龍增進了對於恐龍演化的認識 |《科學報告》 |
論文標題：New Dromaeosaurid Dinosaur (Theropoda, Dromaeosauridae) from New Mexico and Biodiversity of Dromaeosaurids at the end of the Cretaceous
期刊：Scientific Reports
作者：Steven E. Jasinski, Robert M. Sullivan et.al
發表時間：2020/03/26
數字識別碼：10.1038/s41598-020-61480-7
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本周《科學報告》發表的一篇論文New Dromaeosaurid Dinosaur (Theropoda, Dromaeosauridae) from New Mexico and Biodiversity of Dromaeosaurids at the end of the Cretaceous報告發現了一種新型馳龍，馳龍是生活在白堊紀時期的一種身覆羽毛的中小型肉食性動物。化石發現增進了我們對於白堊紀晚期（7000萬-6800萬年前）的恐龍演化的理解。
在Dineobellator notohesperus原始發現地，所指處是骨骼碎片中的前爪。
版權：Steven Jasinski
美國賓夕法尼亞州立博物館的Steven Jasinski及同事在美國新墨西哥州聖胡安盆地的Ojo Alamo地層沉積物裡發現了這種新型馳龍的20塊可辨認骨骼碎片。該恐龍被命名為「Dineobellator notohesperus」，源自納瓦霍語「Diné」（納瓦霍人）和拉丁語「bellator」（勇士）。作者描述了該恐龍一系列獨一無二的特徵，包括靠近尾巴根部的脊椎向內彎曲，這或許能增加敏捷性，提高其捕食成功率。通過化石可以看到該恐龍巨大的鐮狀利爪上有一個圓鑿，作者推測可能是和另一隻Dineobellator或其它獸腳亞目恐龍（如霸王龍）爭鬥導致的。
Dineobellator notohesperus輪廓骨骼復原圖。
作者和版權歸屬Steven Jasinski
物種關係的系統發育分析顯示，Dineobellator可能屬於伶盜龍亞科，其中包括伶盜龍。Dineobellator的祖先被認為從亞洲遷移到北美，可能有多支譜系在北美演化，這或許可以解釋Dineobellator與其他馳龍在形態上的差異。
以上發現補充了原本稀少的馳龍化石記錄，表明這一科的恐龍在白堊紀末、6550萬年前非鳥類恐龍大滅絕之前，仍在發生分化。
Dineobellator notohesperus與新墨西哥白堊紀晚期Ojo Alamo組的其他恐龍的藝術復原圖。
版權：Sergey Krasovskiy
Dineobellator notohesperus藝術復原圖。
作者：Mary P. Williams 版權：Steven Jasinski
摘要：Dromaeosaurids (Theropoda: Dromaeosauridae), a group of dynamic, swift predators, have a sparse fossil record, particularly at the time of their extinction near the Cretaceous-Paleogene boundary. Here we report on a new dromaeosaurid, Dineobellator notohesperus, gen. and sp. nov., consisting of a partial skeleton from the Upper Cretaceous (Maastrichtian) of New Mexico, the first diagnostic dromaeosaurid to be recovered from the latest Cretaceous of the southern United States (southern Laramidia). The holotype includes elements of the skull, axial, and appendicular skeleton. The specimen reveals a host of morphologies that shed light on new behavioral attributes for these feathered dinosaurs. Unique features on its forelimbs suggest greater strength capabilities in flexion than the normal dromaeosaurid condition, in conjunction with a relatively tighter grip strength in the manual claws. Aspects of the caudal vertebrae suggest greater movement near the tail base, aiding in agility and predation. Phylogenetic analysis places Dineobellator within Velociraptorinae. Its phylogenetic position, along with that of other Maastrichtian taxa (Acheroraptor and Dakotaraptor), suggests dromaeosaurids were still diversifying at the end of the Cretaceous. Furthermore, its recovery as a second North American Maastrichtian velociraptorine suggests vicariance of North American velociraptorines after a dispersal event during the Campanian-Maastrichtian from Asia. Features of Dineobellator also imply that dromaeosaurids were active predators that occupied discrete ecological niches while living in the shadow of Tyrannosaurus rex, until the end of the dinosaurs』 reign.
（來源：科學網）
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