デボニアン時代,アルトロダイア胚と脊椎動物における内受精の起源
John A Long1, Kate Trinajstic, Zerina Johanson
1Museum Victoria, PO Box 666, Melbourne 3001, Victoria, Australia. jlong@museum.vic.gov.au
Nature
|February 27, 2009
まとめ
Arthrodira魚で発見された化石胚は,内部受精と生産 (viviparity) が初期のの脊椎動物で一般的であったことを明らかにしています. これは,古代の脊椎動物の生殖戦略に関する以前の仮定に異議を唱えている.
科学分野:
- パレオントロジー・パレオントロジー
- 脊椎動物学 脊椎動物学
- 進化生物学の進化生物学について
背景:
- 生殖生物学の証拠は,化石記録では稀である.
- 以前の発見では,プティクトドンチド (Placodermi) の胚を特定し,冠群Gnathostomataの外での生殖性を示唆した.
- プラコダーミ (Placodermi) は,絶滅した装甲魚の一種である.
研究 の 目的:
- "Arthrodira"の標本で胚を発見したことを報告するためです.
- この多種多様なプラコダーム群の内部受精の証拠を提供するためです.
- 上部デボニアムゴゴ群のIncisoscutum ritchieiの生殖戦略を調査する.
主な方法:
- Incisoscutum ritchieiの標本に関する化石分析.
- プレコダームとコンドリヒチアンの骨盤帯の比較骨格分析.
- 解剖学的類似性に関する系統遺伝的解釈.
主要な成果:
- 胚は,Arthrodira (Incisoscutum ritchiei) の標本の中に発見されました.
- 証拠は,このグループにおける内部受精と生殖性を示唆しています.
- Incisoscutumとphyllolepid arthrodiresの骨盤帯は,交尾時に骨盤が使用されたことを示しています.
- 骨格の類似性は,収束進化 (ホモプラシー) に起因する.
結論:
- 内部受精と生殖は,初期のグナトストームに広く存在していた.
- この発見は,脊椎動物の生殖進化に関する私たちの理解を広げています.
- この研究は,Arthrodira.の内部受精を用いた生殖の最初の証拠を提供します.
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