ラゴモルファの幹とグリレスの古代
Robert J Asher1, Jin Meng, John R Wible
1Museum für Naturkunde, Humboldt Universität, Invalidenstrasse 43, 10115 Berlin, Germany. robert.asher@museum.hu-berlin.de
Science (New York, N.Y.)
|February 19, 2005
まとめ
モンゴルのゴムフォス・エルケマの化石は,ウサギとピカの祖先である初期のラゴモルフであることを明らかにしています. この発見は,白亜紀と地質期の境界付近の哺乳類のケノゾイク期の放射線を明らかにしている.
科学分野:
- パレオントロジー・パレオントロジー
- 哺乳類の進化について
- バイオストラティグラフィー
背景:
- ラゴモルフ (ウサギ,ウサギ,ピカ) は,稀な化石記録を持つ重要な胎盤哺乳類です.
- 彼らの進化的起源を理解することは,初期のケノゾーイク哺乳類の多様化を再構築するために極めて重要です.
研究 の 目的:
- モンゴルの新しいゴムフォス・エルケマ化石を記述するために.
- 胎盤哺乳類におけるゴムフォスの系統的位置を決定する.
- ラゴモルフとネズミの分岐のタイミングを調査する.
主な方法:
- ゴムフォス・エルケマの化石の記述と比較解剖学.
- 頭骨格の特徴を用いた系統遺伝分析.
- パレオセーヌ・エオセーヌ境界付近の化石堆積物の生物層学的な年代測定.
主要な成果:
- Gomphos elkemaの化石は,モンゴルのTsagan Khushuから確認され,旧生代とエオセンの境界まで遡る.
- ゴムフォスは現代のラゴモルフの特徴を示しているが,原始的な歯との構造を保持している.
- 系統遺伝学的な分析では,ゴムホスを幹のラゴモルフとして位置づけ,冠群放射線より前のものである.
結論:
- Gomphos elkemaは初期のラゴモルフを代表し,グループの起源についての洞察を提供します.
- この発見は,ケノゾーイクにおけるラゴモルフとネズミの放射線の仮説を裏付けている.
- ラゴモルフを含む胎盤哺乳類の分岐は,白亜紀と三次紀の境界付近で起こった可能性が高い.
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