新しい化石種が,歯のあるクジラの初期の起源を支持しています
Jonathan H Geisler1, Matthew W Colbert2, James L Carew3
1Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Northern Boulevard, Old Westbury, New York 11568, USA.
Nature
|March 28, 2014
まとめ
新しい化石のクジラ,コティロカラ・マセイ (Cotylocara macei) は,初期オリゴセンの歯のあるクジラ (オドントセテス) で原始的なエコロケーションが進化したことを示唆している. この適応は,フィルター食クジラから分離した直後に発生し,頭蓋骨の進化に影響を与えた.
科学分野:
- パレオントロジー・パレオントロジー
- マリン・バイオロジー マリン・バイオロジー
- 進化生物学の進化生物学について
背景:
- オドントセテス (歯のあるクジラ,イルカ,豚豚) は,水中の環境で航行および狩猟のためにエコーロケーションを使用します.
- オドントセテにおけるエコーロケーションの進化的起源と解剖学的発展は,ほとんど不明のままである.
- エコロケーションは,空気鼻とメロンによって調節される高周波の発声を生成することを含む.
研究 の 目的:
- 歯のあるクジラにおけるエコーロケーションの初期の進化を調査する.
- 新しく発見されたオリゴセンのオドントーセト化石,コティロカラ・メイ (Cotylocara macei) を分析し,エコーロケーションの証拠を探した.
- エコロケーションのタイミングと解剖学的前駆者を推論する.
主な方法:
- サウスカロライナ州から発見された新しい化石オドントケテス (Cotylocara macei) の発見と記述.
- 化石の頭蓋骨の特徴の分析は,エコーロケーション (ロストラム,エアサックフォサエ,頭蓋骨の非対称性,マキシラエ) と潜在的に関連している.
- オドントオセチ内での化石の進化的位置を決定するための系統遺伝分析.
主要な成果:
- Cotylocara maceiは,密集した,下向きのロストラムと頭蓋骨の非対称性を含む,エコーロケーションを示唆するいくつかの特徴を示しています.
- 系統遺伝学的分析により,コティロカラはオドントーセテスの基礎基層に分類される.
- これらの発見は,原始的なエコロケーションがオリゴセンの初期に進化したことを示唆しています.
結論:
- エコロケーションの原始的な形態は,ミスティケテスから分岐した直後に,オリゴセンの初期のオドントセテスで進化した可能性が高い.
- エコロケーションの進化は,顔の筋肉の拡大と関連しており,頭蓋骨の形態学に収束的な変化をもたらしました.
- Cotylocara maceiは,歯のあるクジラにおけるこの重要な感覚的適応の初期段階に関する重要な証拠を提供します.
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