胎盤哺乳類の生命の歴史の起源
Gregory F Funston1,2, Paige E dePolo3, Jakub T Sliwinski4
1School of GeoSciences, University of Edinburgh, Edinburgh, UK. Gregory.Funston@ed.ac.uk.
Nature
|August 31, 2022
まとめ
パントランブダ・バトモドンのような初期の胎盤哺乳類は 妊娠期間が長く 離乳期間が短く 早く繁殖したので 幼い幼虫の時期を示しています 恐竜の絶滅後の急速な多様化と 大きさの増加に寄与しました
科学分野:
- 古生物学
- 進化生物学
- 哺乳類の繁殖
背景:
- クレータ紀末期の絶滅の後,胎盤哺乳類は急速な多様化とサイズ増加を経験した.
- 早期の胎盤哺乳類の生殖戦略はほとんど知られず,その進化の成功の理解を妨げている.
研究 の 目的:
- 初期の胎盤哺乳類の生命史を 化石の証拠を用いて調査する.
- 哺乳類の胎盤の生殖と発達を 最古の記録にするため
- 哺乳類の多様化と 大きさの増加を促す 進化的圧力を理解する
主な方法:
- パレオヒストロジーと地化学が6200万年前のパントドント化石 (Pantolambda bathmodon) に使われた.
- 歯の微量元素のマッピングは,出生と離乳時の化学マーカーを特定するために使用されました.
- 歯並びの毎日の成長は,発達時間軸を再構築するために調整されました.
主要な成果:
- 妊娠期間は約7ヶ月とされています
- 歯の発達は迅速で,哺乳期は30~75日でした.
- パントランブダ・バトモドンは,胎盤以外の哺乳類とは異なり,非常に早熟した生命の歴史を示した.
結論:
- パントランブダ・バトモドンは,現代の胎盤哺乳類と似て生殖し,生命の歴史のペースが速い.
- 十分に発達した幼虫を産む能力は胎盤の進化の初期に確立された可能性が高い.
- 急速な発達と新生児の大きさは,早期の胎盤で観察された重要な体積増加を容易にした可能性があります.
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