| Co-Investigator(Kenkyū-buntansha) |
MAEDA Haruyoshi Kyoto University Fac. Science Research Assoc, 理学部, 助手 (10181588)
KAMIYA Hidetoshi Kyoto University Fac. Science Research Assoc, 理学部, 助手 (00115825)
SHIMIZU Daikichiro Kyoto University Fac. Science Lecturer, 理学部, 講師 (60025327)
OHONO Terufumi Kyoto University Fac. Science Assoc. Prof, 理学部, 助教授 (40194245)
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| Research Abstract |
Functionally meaningful structures in the organic hard tissues are those of the mesoscopic scale, having orders of millimeter to several tens of micrometers, rather than their ultramicrostructures. However, little attention has been paid for the structure of the mesoscopic order by researchers of the fossil and living hard tissues. We started this study first to describe the structures of the mesoscopic scale at the view point of their functions. We studied lightweight structure of bivalves and other structures shown below, described their processes of construction, and discussed their implications to these functions.
The lightweight structures seen in the oyster shells are cavernous construction, which morphologies are specific to the oyster species, box-work in Crassostrea, honeycomb structure in Hyotissa, etc. They make oyster shells lightweight and enable them to live on soft muddy substrates. In oyster shells, we found a particular structure, named the ridge-and-furrow structure, at the place of cementation to the hard substrates. The structure is functional for the cementation. Structure of the septal neck in Spilura and pillar structure of cuttlebone, cephalopods, are described and discussed in relation to the control of their buoyancy. Some species of the family Venerdae have minute calcified needles of hexagonal cross-section. These needles are concluded to improve the stability of the life position in sediments. Also, we discussed about the transparent structure of strawberry cockles in relation to symbiosis with photosymbiotic algae, and laminated structure of the enamel layr in mammal teeth.
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