在西班牙Las Hoyas發(fā)現(xiàn)的一種中等大小恐龍的一個幾乎完整的,、保存非常完好的骨架,，對于有關羽狀結構作用和起源的辯論有參考價值,。新發(fā)現(xiàn)的“鯊齒龍”在尺骨上有所謂的“正羽”，這使得它成為已知具有這種特征的最基礎的獸腳恐龍,，也擴大了解釋這一亞類恐龍中羽毛起源的可能性范圍,。
不過更為神秘的是，這種恐龍有一個駝峰狀的結構,，源自神經(jīng)棘,，在兩個胸椎上，沒有明顯功能,。（生物谷Bioon.com）
生物谷推薦英文摘要：
Nature doi:10.1038/nature09181
A bizarre, humped Carcharodontosauria (Theropoda) from the Lower Cretaceous of Spain
Francisco Ortega,[email protected] Escaso& José L. Sanz
Carcharodontosaurs were the largest predatory dinosaurs, and their early evolutionary history seems to be more intricate than was previously thought. Until recently, carcharodontosaurs were restricted to a group of large theropods inhabiting the Late Cretaceous Gondwanan land masses1, 2, but in the last few years Laurasian evidence3, 4, 5 has been causing a reevaluation of their initial diversification6. Here we describe an almost complete and exquisitely preserved skeleton of a medium-sized (roughly six metres long) theropod from the Lower Cretaceous series (Barremian stage) Konservat-Lagerst?tte of Las Hoyas7 in Cuenca, Spain. Cladistic analysis supports the idea that the new taxon Concavenator corcovatus is a primitive member of Carcharodontosauria6, exhibiting two unusual features: elongation of the neurapophyses of two presacral vertebrae forming a pointed, hump-like structure and a series of small bumps on the ulna. We think that these bumps are homologous to quill knobs present on some modern birds; the knobs are related to the insertion area of follicular ligaments that anchor the roots of the flight feathers (remiges) to the arm. We propose that Concavenator has integumentary follicular structures inserted on the ulna, as in modern birds. Because scales do not have follicles, we consider the structures anchored to the Concavenator arms to be non-scale skin appendages homologous to the feathers of modern birds. If this is true, then the phylogenetic bracket for the presence of non-scale skin structures homologous to feathers in theropod dinosaurs would be extended to the Neotetanurae, enlarging the scope for explaining the origin of feathers in theropods.
