幹骨イチアン・アンドレオレピスと歯の入れ替えの起源

Donglei Chen¹, Henning Blom¹, Sophie Sanchez^2,3

¹Uppsala University, Department of Organismal Biology, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.

Nature

|November 4, 2016

まとめ

の脊椎動物には歯の置換メカニズムが多様です 4億2400万年前の魚の化石 Andreolepis hedeiは吸い込みによる早期の歯の脱落を示し脊椎動物の歯の進化の洞察を示しています

科学分野:

古生物学
進化生物学
脊椎動物学

背景:

グナトストーム (椎動物) の歯の置換パターンは多様で,歯の維持に不可欠です.
歯の膜や再吸収による歯の脱落などのメカニズムは既存の種間で不均等に分布しています
脊椎動物の歯の進化をたどるには原始的な歯の置換を理解することが重要です

研究の目的:

古代オステイチアンの歯の置換メカニズムを調査する
アンドロエレピスの成長経緯と歯の脱出過程を再現する
オステイキシアンにおける吸収性歯の脱落の最古の発生を特定するためです

主な方法:

拡散相対照シンクロトロンマイクロトモグラフィーを用いた3次元仮想解剖
アンドロエレピス・ヘデイの歯構造の詳細分析
歯の成長と入れ替えの歴史の再構築

主要な成果:

アンドレオレピス・ヘデイは初期オステイキシアンで基礎硬組織の再吸収によって歯が落ちる
この化石には永久的な歯の膜がなく異なる発達経路を示唆しています
これは再吸収性歯の脱落を記録した最古の証拠です

結論:

吸い取れる歯の脱落は,骨格生物における歯の置換の原始的な方法であった.
Andreolepis hedeiは脊椎動物の歯の初期の進化について重要な洞察を与えてくれます
この発見は歯の置換メカニズムの祖先状態に関する以前の仮定に異議を唱えるものです

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