Crystallographic texture analysis of Protobranchia (Mollusca: Bivalvia): interspecific variations, homology and shell microstructural evolution
Crystallographic texture analysis of Protobranchia (Mollusca: Bivalvia): interspecific variations, homology and shell microstructural evolution
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原鳃亚纲（软体动物：双壳纲）的晶体结构分析：种间变异、同源性和壳微结构演化
DOI：
10.1093/mollus/eyx021
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发表时间：
2017
影响因子：
1.2
通讯作者：
Sasaki Takenori
中科院分区：
文献类型：
--
作者：
Sato Kei;Checa Antonio G.;Rodriguez-Navarro Alejandro B.;Sasaki Takenori
为了更好地了解软体动物壳的微观结构的形成和演化历史，我们分析了晶体学纹理的壳的微观结构的选择物种的Protobranchia，最古老的双壳类。我们的数据集涵盖了五个原鳃亚纲超家族中的四个。本文分析了珠母贝总科5种、索贝目4种和珠母贝总科7种的壳层结构，并根据它们的结构晶体学模式将它们分为6种不同的类型。我们的研究表明，一些微结构（如径向细长的简单棱柱结构）具有结构特异性纹理图案，而其他微结构（如均匀结构）显示分类特异性差异，尽管形态相似。前者的结果意味着，每个微观结构准确地反映了一个独特的晶体结构，在后者的不一致性，然而，提出了质疑的同源性之间的形态定义的微观结构。与最新的分子系统发育树相比，我们的数据表明，晶体纹理在原鳃类中受到遗传限制。每个珠母贝总科物种都有2 ~ 3种不同的纹理模式，而在Solemyida和Nuculanoidea的每个物种中都有1 ~ 2种相似的纹理模式。在一般情况下，密切相关的物种有相似的晶体结构模式，无论在壳微观结构的差异。
To achieve a better understanding of the formation and evolutionary history of molluscan shell microstructures, we analysed crystallographic textures of shell microstructures of selected species of Protobranchia, the most ancient group of Bivalvia. Our dataset covers four of the five protobranch superfamilies. Shell layers of five species of Nuculoidea, four species of Solemyida and seven species of Nuculanoidea were analysed and classified according to their textural crystallographic patterns into six different types. Our investigation revealed that some microstructures (e.g. the radially elongate simple prismatic structure) have structure-specific textural patterns, while other microstructures (e.g. the homogeneous structure) show taxon-specific differences despite morphological similarities. The former result means that each microstructure accurately reflects a unique crystallographic structure; the inconsistency in the latter, however, calls into question the homologies among morphologically defined microstructures. In comparison with the latest molecular phylogenetic trees, our data showed that crystallographic textures are phylogenetically constrained within Protobranchia. Each nuculoidean species had two to three distinct textural patterns, and one or two similar textural patterns were recognized within each species of Solemyida and Nuculanoidea. In general, closely related species had similar crystallographic textural patterns regardless of differences in shell microstructures.