Comparative morphologic and biomineralogical studies on the relationship between mantle differentiation and early shell formation in Mollusca

软体动物地幔分化与早期壳形成关系的比较形态学和生物矿物学研究

基本信息

批准号：
15340175
负责人：
TANABE Kazushige
金额：
$ 8.83万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340175/
关键词：
Mollusca Early ontogeny Larval shell Embryonic shell Comparative morphology biomineralization evolution

项目摘要

In this study, we have examined the relationship between mantle differentiation and shell formation in early developmental satges of Recent and fossil mollusks from the viewpoints of comparative morphology and biomineralogy, and the results of observations were considered for their morphogenetic, larval ecological and phylogenetic implications. The results are summarized as below.A. Embryology and larval shell development of Recent Gastropoda. SEM studies of a freshwater snail Lymnaea stagnalis in the early stages reveal that the early larval shell was not formed accretionarily, and that the biomineralization process in the early stage differs from that in the post-metamorphosis stage.B. Larval shell formation in Recent Bivalvia SEM and TEM studies of a pholadid bivalve Zirfaea subconstricta in the trochophore and early veliger larval stages indicate that outer surface of secreting cells contribute a shell pellicle and functions as an adhering site of tendon cells at the stage of non-biomineralization.C. Embryonic shell development of Mesozoic Ammonoidea Exceptionally well-preserved embryonic shell fossils of Mesozoic ammonites were examined for their shell wall structure and ornament by means of SEM. The results demonstrate the succession of early shell wall development starting with a horny primary shell and ending in the secretion of a nacreous swelling at the aperture via secretion of inner prismatic and outer prismatic layers. Irregular distribution of microtubercles on the outer prismatic layer suggest that they were formed by the aid of a shell gland but by non-biological precipitation by egg-fluid.

在这项研究中，我们从比较形态学和生物媒体学的角度研究了最近和化石软体动物的早期发育和化石软体动物中的地幔分化与壳形成之间的关系，并考虑了观察结果的结果，其形态发生，幼虫生态学和系统发育意义。结果总结如下。近期胃足病的胚胎学和幼虫壳的发展。 SEM在早期阶段对淡水蜗牛lymnaea stagnalis的研究表明，早期的幼虫壳未形成增值，并且早期的生物矿化过程与后型后期的生物矿化过程不同。在最近的bivalvia sem中，幼虫壳的形成和pholadid bivialve zirfaea subctricta的TEM研究和veliger早期的veliger幼虫阶段表明，分泌细胞的外表面促进了壳细胞，并且在非双二层化的阶段造成了壳细胞的粘附位点。中生代氨基化的胚胎壳发育通过SEM检查了中生代氨的胚胎壳化石，并通过SEM检查了其壳壁结构和装饰。结果表明，早期壳壁发育的继承是从角质原发性壳开始，并通过内部棱柱形和外棱柱形层的分泌在孔径上的鼻腔肿胀结束。微晶晶石在外棱镜层上的不规则分布表明，它们是借助壳腺而形成的，但是通过鸡蛋氟化卵形的非生物沉淀而形成的。