Research press release


Scientific Reports

Palaeontology: The arrival of titanosaurs in Australia

竜脚類は、大型の草食恐竜で、首と尾が長い。今週、オーストラリアで生息していた竜脚類の新属新種の骨格化石と別の竜脚類の初めての頭蓋化石について記述されたStephen Poropatたちの論文が掲載される。この2つの化石標本は、白亜紀後期(約9500万年前)のものであり、これらの恐竜がオーストラリアに到達した経緯を明らかにする上で役に立つ可能性がある。

この論文には、オーストラリア北東部のクイーンズランド州にあるウィントン層で見つかった竜脚類の2つの化石標本について記述されている。その1つは新属新種(Savannasaurus elliottorum)の化石だ。Poropatたちは、系統発生解析によって進化上の類縁関係を調べた結果と解剖学的構造をもとに、この竜脚類の2個体がティタノサウルス類の恐竜だったと結論づけている。


A newly identified genus and species of Australian sauropod - a large herbivorous dinosaur with a long neck and tail - and the first cranial remains of an Australian sauropod are described in a paper in Scientific Reports this week. The two specimens from the Late Cretaceous period (approximately 95 million years ago) may help to shed light on how these dinosaurs arrived in Australia.

Stephen Poropat and colleagues describe two specimens of sauropod, including a new species - Savannasaurus elliottorum - found in the Winton Formation of Queensland, northeast Australia. The authors conclude that both sauropods were members of a group of dinosaurs called titanosaurs on the basis of their anatomy and a phylogenetic analysis of their evolutionary relationships.

The authors’ analysis of the prehistoric distribution of this group of dinosaurs suggests that Australian sauropods represent remnants of clades which were found around the world during the Early Cretaceous (around 125 million years ago). They propose that these lineages would have originated in South America and entered Australasia by crossing Antarctica. However, floral evidence suggests that a climatic barrier existed between Antarctica and South America between 120 million and 110 million years ago. The authors hypothesize that the appearance of titanosaurs in Australia around 105 million years ago may have been facilitated by a period of warming that removed the barrier between Antarctica and South America.

doi: 10.1038/srep34467


メールマガジンリストの「Nature 関連誌今週のハイライト」にチェックをいれていただきますと、毎週各ジャーナルからの最新の「注目のハイライト」をまとめて皆様にお届けいたします。