新しい研究によると、ティラノサウルス（T. rex）の小さな腕は、この巨大な捕食性恐竜が狩りにおいて巨大な頭蓋骨と顎を使うようになった過程で進化した可能性が高い。科学者たちは数十種の獣脚類を調査し、前肢の縮小と頑強な頭蓋骨の間に強い相関関係があることを発見した。この研究は、捕食者が獲物を大型化させるにつれて、こうした変化が起きたことを示唆している。
ユニバーシティ・カレッジ・ロンドンとケンブリッジ大学の研究チームは、82種の獣脚類を分析した。その結果、前肢の縮小はティラノサウルス科を含む少なくとも5つの系統でそれぞれ独立して進化したことが判明した。短い腕と強力な頭蓋骨の結びつきは、体格全体との関連性よりも強いことが証明された。
A nearly complete skeleton of a small predatory dinosaur discovered in Argentina has revealed new details about the evolution of alvarezsaurs. The 95-million-year-old Alnashetri cerropoliciensis weighed just 700 grams and challenges previous ideas about their anatomy and diet. Researchers suggest it had a broader range of prey than previously thought.
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Small fossils of Liaoningosaurus paradoxus, once thought to represent a miniature species of armored dinosaur, have been confirmed as juveniles, including some less than a year old and a possible hatchling. Researchers analyzed bone growth patterns to reach this conclusion, challenging earlier ideas about the animal's size and lifestyle. The discovery provides insights into early development of ankylosaurs.
A new study suggests that the disappearance of massive herbivores in the Levant around 200,000 years ago prompted early humans to switch from heavy stone tools to lighter, more sophisticated ones. Researchers at Tel Aviv University analyzed archaeological sites and found this tool revolution coincided with a drop in large prey and a rise in smaller animals. The findings, published in Quaternary Science Reviews, propose that hunting smaller prey may have driven cognitive evolution.
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Researchers have uncovered evidence that octopuses from the Late Cretaceous period, around 100 million years ago, grew to lengths of nearly 20 meters and hunted as top predators. The findings, based on well-preserved fossil jaws from Japan and Vancouver Island, challenge previous views of early octopus evolution. Professor Yasuhiro Iba of Hokkaido University led the study, published in Science on April 23.