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Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
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最古の幹四足動物における脊椎構造
Stephanie E Pierce1, Per E Ahlberg, John R Hutchinson
1University Museum of Zoology, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. spierce@rvc.ac.uk
Nature
|January 22, 2013
まとめ
初期の四足類の脊椎の進化が修正されています. この研究は,
科学分野:
- パレオントロジー・パレオントロジー
- 脊椎動物の解剖学について
- 進化生物学の進化生物学について
背景:
- 脊柱の構造は,早期の四足類群の診断の鍵である.
- ラキトモス脊椎は伝統的に四足類の祖先と考えられています.
- 保存上の問題のために,最も初期の幹四足の脊椎解剖学に関する知識は限られている.
研究 の 目的:
- 幹四足体のイチソステガの3Dの脊椎構造を説明するために.
- 先進的なイメージングを使用して,初期の四足体の脊椎解剖学を調査するために.
- 初期の四足類における脊柱の進化に関する理解を修正する.
主な方法:
- 利用された伝播相対照X線シンクロトロンマイクロトモグラフィー.
- イチソステガの脊椎構造を分析した.
- 脊椎の形状をアカントホステガとペデルペスと比較した.
主要な成果:
- 多様な新しい形態学的,発達的,機能的な特徴を明らかにした.
- イチオステガの"逆"のラキトーム性脊椎構造を特定し,その Pleurocentra と Intercentra が融合した.
- 脊椎の後部から前部への骨化シーケンスと最初の骨化した胸骨の要素を観察した.
結論:
- "逆"のラキトム性脊椎構造は,四肢を持つ脊椎動物の祖先の条件かもしれない.
- この発見は,テトラポッドの初期の脊椎進化に関する現在の理解を根本的に修正するものである.
- テトラポドモルフ魚とクラウンワードテトラポッドの推定脊椎構造に関する疑問を提起する.
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