作者
Alan H Turner, Diego Pol, Julia A Clarke, Gregory M Erickson, Mark A Norell
发表日期
2007/9/7
期刊
Science
卷号
317
期号
5843
页码范围
1378-1381
出版商
American Association for the Advancement of Science
简介
Fossil evidence for changes in dinosaurs near the lineage leading to birds and the origin of flight has been sparse. A dinosaur from Mongolia represents the basal divergence within Dromaeosauridae. The taxon's small body size and phylogenetic position imply that extreme miniaturization was ancestral for Paraves (the clade including Avialae, Troodontidae, and Dromaeosauridae), phylogenetically earlier than where flight evolution is strongly inferred. In contrast to the sustained small body sizes among avialans throughout the Cretaceous Period, the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Thus, change in theropod body size leading to flight's origin was not unidirectional.
引用总数
学术搜索中的文章
AH Turner, D Pol, JA Clarke, GM Erickson, MA Norell - Science, 2007