古代の顎のない魚の3D口は、魚がスカベンジャーやハンターではなく、フィルターフィーダーであったことを示唆している(3D mouth of an ancient jawless fish suggests they were filter-feeders, not scavengers or hunters)

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2024-04-10 バーミンガム大学

バーミンガム大学の専門家らは、CTスキャン技術を用いて、最初の脊椎動物であるこれらの生物の3D画像を作成しました。彼らは、約4億年前のデボン紀初期の無顎の初期脊椎動物の摂食に関する疑問に答えることを目指しました。今回の研究では、ジャウレスな魚の1つである「Rhinopteraspis dunensis」の口の部分を詳細に視覚化しました。CTスキャン技術の応用により、これらの古代脊椎動物に関する新しい情報が明らかになり、破壊的な調査を行うことなく貴重な標本を研究する機会が得られました。

<関連情報>

デボン紀のヘテロストラカンの3次元的に連結された口腔器具が古生代の無顎魚の摂食に光を当てる The three-dimensionally articulated oral apparatus of a Devonian heterostracan sheds light on feeding in Palaeozoic jawless fishes

Richard P. Dearden,Andy S. Jones,Sam Giles,Agnese Lanzetti,Madleen Grohganz,Zerina Johanson,Stephan Lautenschlager,Emma Randle,Philip C. J. DonoghueandIvan J. Sansom
Proceedings of the Royal Society B  Published:27 March 2024
DOI:https://doi.org/10.1098/rspb.2023.2258

古代の顎のない魚の3D口は、魚がスカベンジャーやハンターではなく、フィルターフィーダーであったことを示唆している(3D mouth of an ancient jawless fish suggests they were filter-feeders, not scavengers or hunters)

Abstract

Attempts to explain the origin and diversification of vertebrates have commonly invoked the evolution of feeding ecology, contrasting the passive suspension feeding of invertebrate chordates and larval lampreys with active predation in living jawed vertebrates. Of the extinct jawless vertebrates that phylogenetically intercalate these living groups, the feeding apparatus is well-preserved only in the early diverging stem-gnathostome heterostracans. However, its anatomy remains poorly understood. Here, we use X-ray microtomography to characterize the feeding apparatus of the pteraspid heterostracan Rhinopteraspis dunensis (Roemer, 1855). The apparatus is composed of 13 plates arranged approximately bilaterally, most of which articulate from the postoral plate. Our reconstruction shows that the oral plates were capable of rotating around the transverse axis, but likely with limited movement. It also suggests the nasohypophyseal organs opened internally, into the pharynx. The functional morphology of the apparatus in Rhinopteraspis precludes all proposed interpretations of feeding except for suspension/deposit feeding and we interpret the apparatus as having served primarily to moderate the oral gape. This is consistent with evidence that at least some early jawless gnathostomes were suspension feeders and runs contrary to macroecological scenarios that envisage early vertebrate evolution as characterized by a directional trend towards increasingly active food acquisition.

生物工学一般
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