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リンコサウルスの組織学 (Diapsida, Archosauromorpha) アンキロテコドンティ

Gabriel Mestriner^1,2,3, Gregory F Funston^3,4,5, Sterling J Nesbitt⁶

¹Departamento de Biologia, Universidade de São Paulo, Ribeirão Preto, Brazil.

Journal of anatomy

|August 28, 2025

まとめ

リンコサウルスの歯は,以前は単に融合 (アンキロシス) であったと考えられていましたが,哺乳類や恐竜に似た複雑な結合組織を示しています. これは,歯の付着の多様性を脊椎動物で説明できるのは進化の変化による鉱化タイミングであって収束的な進化ではないことを示唆している.

科学分野:

古生物学
脊椎動物古生物学
進化生物学

背景:

歯との繋がりの進化は脊椎動物の古生物学にとって重要なものです
アルコサウルモルフの歯の付着は異なるが,恐竜/クロコディリアンではゴムフォシス,関連群ではアンキロシスがある.
幹とアーコサウルスの歯の結合を理解することで進化のシフトが明らかになります

研究の目的:

脊椎動物の歯の付着の進化を理解するために,リンコサウルスの歯の付着を分析する.
リンコサウルスの歯の付着の組織学的性質を調査する.
アルコサウルモルファの歯付着組織の同質性を明らかにする.

主な方法:

中期トライアスのラインコサウルスの3つのサンプルを分析した
歯の発達段階を調べる
歯の付着組織の比較分析

主要な成果:

リンコサウルスの歯はアンキロシスを表しますが,シャーピーの繊維,セメント,アルベオラの骨は,ゴムフォシスの組織に似ています.
リンコサウルスの"スポンジ状の結合骨"は,鉱化したゴムフォシスのような組織で構成されています.
リンコサウルスのアンキロシスは,歯周関節を鉱化させるアルベオラ骨の成長に起因する.

結論:

リンコサウルスの歯の付着組織は哺乳類,恐竜,ワニの歯と同類である.
ミネラライゼーションのタイミングにおけるヘテロクロニックな変化は,コンバージェントな進化ではなく,ゴムフォシスの独立した進化を説明する.
この研究は,アーコサウルモルファや他の乳芽類における歯の付着進化の理解を洗練している.

キーワード:

アンキロテコドントアルベオラ骨アンキロシス歯科ヒストロジーヘテロクロニー歯の固定装置

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