カンブリア紀初期のサスペンション栄養のアノマロカリド
Jakob Vinther1, Martin Stein2, Nicholas R Longrich3
1Schools of Earth Sciences and Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
Nature
|March 28, 2014
まとめ
古代のアノマロカリドのような大型懸浮餌器は,カンブリア爆発時に初めて進化した. これらの初期の海洋動物は,小さなプランクトンにフィルターで餌を与えるための特殊な付属体を用いており,複雑なカンブリア時代の生態系を示しています.
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:
- 大きく,活発に泳ぐサスペンションフィーダーは,地球の歴史を通じて何度も進化しました.
- これらの栄養戦略は,クジラや魚を含む様々な集団から知られていますが,初期のパレオゾーイク時代から知られていません.
- アノマロカリドはカンブリア紀とオルドビキア紀の支配的なネクトニク動物で,以前は頂点の捕食動物と考えられていた.
研究 の 目的:
- カンブリア初期のシリウス・パセット・ファウナからアノマロカリド Tamisiocaris borealisの食習慣を調査する.
- アノマロカリド,特にT. borealisがサスペンションで餌を食ったかどうかを判断する.
- 大型のネクトン式懸浮フィーダーの進化的起源と,初期の生態系におけるその役割を理解する.
主な方法:
- タミシオカリス・ボレアリス (Tamisiocaris borealis) の新しい化石素材の記述
- 脊椎と補助脊椎を含む前肢の形状の分析.
- 付属体の構造と,既知のサスペンション給餌機構の比較.
主要な成果:
- T. borealisの正面付属体は,長い細い腹部棘と細い補助棘で記述されています.
- この形態学は,微生物 suspension feedingの専門化を示唆し,0.5mmほど小さい食物粒子を捕捉しています.
- T. borealisは,スイープネット捕獲法を使用して,コペポッドなどのメゾゾープランクトンで食べた可能性が高い.
結論:
- 大きなネクトン suspension feederは,アノマロカリドの適応放射線の中でカンブリア爆発の間に発生しました.
- T. borealisの存在は,サスペンション・フィーディングがこれまで考えられていたよりも早く進化したことを示しています.
- 初期のカンブリア海域の生態系は複雑で,高い一次生産性と栄養素の流れによって支えられ,多様な植物プランクトンとメソゾープランクトンコミュニティが特徴でした.
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