Moulton D E, Goriely A, Chirat R
Mathematical Institute, University of Oxford, Oxford, UK.
UMR CNRS 5276, Université Lyon 1, France.
J Theor Biol. 2015 Jan 7;364:220-30. doi: 10.1016/j.jtbi.2014.09.021. Epub 2014 Sep 26.
Ammonites are a group of extinct cephalopods that garner tremendous interest over a range of scientific fields and have been a paradigm for biochronology, palaeobiology, and evolutionary theories. Their defining feature is the spiral geometry and ribbing pattern through which palaeontologists infer phylogenetic relationships and evolutionary trends. Here, we develop a morpho-mechanical model for ammonite morphogenesis. While a wealth of observations have been compiled on ammonite form, and several functional interpretations may be found, this study presents the first quantitative model to explain rib formation. Our approach, based on fundamental principles of growth and mechanics, gives a natural explanation for the morphogenesis and diversity of ribs, uncovers intrinsic laws linking ribbing and shell geometry, and provides new opportunities to interpret ammonites' and other mollusks' evolution.
菊石是一类已灭绝的头足类动物，在一系列科学领域引起了极大关注，并且一直是生物年代学、古生物学和进化理论的范例。它们的显著特征是螺旋几何形状和肋纹图案，古生物学家通过这些来推断系统发育关系和进化趋势。在此，我们开发了一个菊石形态发生的形态力学模型。虽然已经积累了大量关于菊石形态的观察资料，并且可以找到几种功能解释，但本研究提出了第一个解释肋纹形成的定量模型。我们基于生长和力学基本原理的方法，对肋纹的形态发生和多样性给出了自然的解释，揭示了连接肋纹和壳体几何形状的内在规律，并为解释菊石及其他软体动物的进化提供了新的机会。
