クレータ紀のオルニチューリンは,ネオグナトス王冠鳥の祖先を支えている
Juan Benito1, Pei-Chen Kuo2, Klara E Widrig2
1Department of Earth Sciences, University of Cambridge, Cambridge, UK. jb2284@cam.ac.uk.
Nature
|November 30, 2022
まとめ
新しい化石の鳥 ジャナビス・フィナリデンスは 現代の水鳥や陸鳥に似た の構造を明らかにしています この発見は,この口腔型が全ての鳥の祖先である可能性を示唆し,初期の鳥の進化に関する以前の仮定に異議を唱えます.
科学分野:
- 古生物学
- 進化生物学
- 比較解剖学
背景:
- ネオグナテア (合体していない口腔,動的頭蓋骨) とパラエオグナテア (合体した口腔,硬い頭蓋骨) と区別する.
- パレオグナテのが合体した状態は,長らく冠鳥 (ネオニテス) の祖先と考えられてきました.
- 初期のネオルニチン palatesの化石証拠は稀であり,祖先の特徴の理解を制限しています.
研究 の 目的:
- コロナ鳥 (ネオニテス) の祖先の口腔状態を調査する.
- 鳥の食欲の進化に関する 古い仮説を再考する
- 中生期のオルニチューリンの系統的位置と口腔の形状を明らかにする.
主な方法:
- クレタ紀末期の新しい化石分類種である Janavis finalidens の記述と分析.
- ジャナビスの口腔と現存する鳥類 (ネオグナテア,パレオグナテア) と他の化石分類の形態学的比較分析.
- ジャナビスを既存の鳥類の進化の枠組みに組み込む 系統遺伝分析
主要な成果:
- Janavis finalidensは,現存するネオグナス,特にGalloanserae (水鳥 + 陸鳥) に著しく類似したペトリゴイド骨を持っています.
- ジャナビスはイチヨルニスのほか,イチヨルニスの最初の代表者であり,クレタセア紀の末期まで続いていたことを確認している.
- この発見は,メソゾイク期の非冠状鳥類に,解剖学的にネオグナトスながあることを示しており,これは冠状鳥類のプレシオモルフィックな特徴である可能性を示唆している.
結論:
- ジャナビスの口腔の構造は 合体した口腔が 冠鳥の祖先だったという仮定に 異議を唱えます
- 現存するGalloanseraeに類似するペトリゴイドの形態は,冠鳥のプレシオモルフィックである可能性があります.
- これらの結果は,ペラゴーニシダのような初期のケノゾイク鳥群の進化的関係と親和の再評価を必要とします.
関連する概念動画
Convergent Evolution
28.2K
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
28.2K
The Fossil Record
25.4K
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
25.4K
Phylogeny
45.3K
Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon (singular). Taxa (plural) can span different levels of the evolutionary hierarchy. For instance, the group containing all birds is a taxon (comprising the class Aves), and the group of all species of daisies (the genus Bellis) is a taxon. Phylogenies can likewise include just one genus (i.e., depict species relationships) or span an entire kingdom.
45.3K
The Evidence for Evolution
43.3K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
43.3K
Optimal Foraging
12.4K
How animals obtain and eat their food is called foraging behavior. Foraging can include searching for plants and hunting for prey and depends on the species and environment.
12.4K
Tooth Anatomy
882
The human tooth enables us to eat a variety of foods, speak clearly, and even aid in shaping our faces. Teeth are composed of various elements that work together. Here's a detailed look at the anatomy of a human tooth.
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or...
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or...
882


