北米における馬の食生活の変化と進化
Matthew C Mihlbachler1, Florent Rivals, Nikos Solounias
1Department of Anatomy, New York College of Osteopathic Medicine, Old Westbury, NY 11568, USA. mmihlbac@nyit.edu
Science (New York, N.Y.)
|March 10, 2011
まとめ
馬の歯の高さは草原の拡大とともに進化したが,食生活による磨きは時間とともに大きく変化した. 高冠の歯に対するより強い選択は,特定の間隔で,特にエキナエ亜族が現れる前に起こった.
科学分野:
- パレオントロジー・パレオントロジー
- 進化生物学の進化生物学について
- 哺乳類の歯の形態学
背景:
- 馬 (馬科) の高冠の歯は,荒草地での食生活への適応であると考えられている.
- 歯のメソウェアは,シュープの鋭さとリフレクションを反映し,食事による摩擦の代理として機能します.
- 馬のモラー進化を理解することで,環境の変化への適応の洞察が得られます.
研究 の 目的:
- 過去5550万年の間,北米の馬類におけるモラー冠の高さと食物の磨きとの関連を検証する.
- メソウェアの傾向が,地球温暖化と植生の変化とどのように相関するかを調査する.
- 馬の歯の進化の有意な選択的圧力の時期を特定するために.
主な方法:
- 化石の北米の馬類からのメソウェアデータの収集と分析.
- 歯のメソウェアに基づいて食事による磨損レベルを再構築.
- メソウェアパターン,冠の高さ,地質/気候データとの相関分析.
主要な成果:
- 強い正の相関がモラー冠の高さと馬のメソウェアの間に存在する.
- メソウェアのトレンドは,一般的に,地球温暖化とそれに関連する植生の変化を反映しています.
- ほとんどの馬古集団は,食事による摩擦の高変動を示しており,冠の高さに対する選択的圧力の変動を示しています.
結論:
- 冠の高さと摩擦の間の一般的な相関は存在するが,高冠の歯の選択的圧力は一定ではなかった.
- 特定の間隔,特にミオセンの初期にEquinaeサブファミリーに先立つ間隔は,歯の進化のために磨きが増加し,より強い選択の証拠を示しています.
- 馬の高い冠の歯の進化は,草原の一貫した拡張の影響を受けたが,それだけでは引き起こされなかった.
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