中国のジュラ紀のケラトサウルスは,鳥類のデジタルホモロジーを明らかにするのに役立ちます
Xing Xu1, James M Clark, Jinyou Mo
1Institute of Vertebrate Paleontology and Paleoanthropology, Beijing 100044, China. xingxu@vip.sina.com
Nature
|June 19, 2009
まとめ
テロポッド恐竜の手の進化は複雑である. 新しい中国のケラトサウルスの化石は,縮小された数字Iを明らかにし,セロポッドのデジタル縮小パターンに関する以前の仮定に挑戦し,テトラポッドの進化の間に数字のアイデンティティのシフトを示唆しています.
科学分野:
- パレオントロジー・パレオントロジー
- 脊椎動物の進化について
- 恐竜の古生物学について
背景:
- 伝統的な見方:セロポッドは横向きに内側に指をなくした (I-II-III).
- 発達に関する研究:現存する鳥 (テタヌラン) はII-III-IVの数字を持っています.
- セロポッドのデジタル縮小パターンに関する矛盾する証拠.
研究 の 目的:
- テロポダのデジタル縮小の複雑なパターンを調査するために.
- 基礎のセロポッドとテタヌランの数字の同一性を再評価する.
- テタヌラ族への移行期における手進化を理解するためです.
主な方法:
- 中国・ジュラ紀の新しい基礎型セラトサウルスの記述.
- 手足の指とメタカルパ/ファランゲの特徴をセロポッド種全体で比較分析した.
- 形態学的比較と発達データに基づく数字のアイデンティティの推論.
主要な成果:
- 最初のアジア系ケラトサウルスの発見,ニキビのある草食動物ジュラ紀のセロポッド.
- この新分類種は,手動で大きく縮小された数字"I"を示しており,複雑な縮小パターンを示しています.
- ベース・テタヌランの手には,メタカルパ (II-III-IV) とファランゲ (I-II-III) が混ざり,よりベース・テラポッドと類似している.
結論:
- 最も単純な解釈では,テタヌランは共通の祖先からII-III-IVの数字のアイデンティティを継承したことを示唆しています.
- Tetanuraeの進化は,数字のアイデンティティのシフトを含む,重要な手の変化を伴いました.
- セラトサウルスは,セロポッドのデジタル進化の中間状態を表しています.
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