A possible mechanism for the formation of annual growth lines in bivalve shells  

作　　者：LIU XiaoJun YAN ZhenGuang ZHENG GuiLan ZHANG GuiYou WANG HongZhong XIE LiPing ZHANG RongQing 

机构地区：[1]Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China [2]Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing 100084, China [3]Key Lab of Ecological Effect and Risk Assessment for Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China

出　　处：《Science China(Life Sciences)》2011年第2期175-180,共6页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. U0831001 and 40876068);the National High Technology Research and Development Program of China (Grant Nos. 2010CB126405 and 2010AA09Z405)

摘　　要：We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.All the characteristics of the growing margin indicated that the shell was growing rapidly.To explain this anomaly,we propose the concept of "jumping development".During jumping development,the center of growth in the bivalve shell jumps forward over a short time interval when the position of the mantle changes.Jumping development explains the unusual structure of the anomalous shell and the development of annual growth lines in typical shells.Annual growth lines are the result of a discontinuity in the shell microstructure induced by jumping development.We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.All the characteristics of the growing margin indicated that the shell was growing rapidly.To explain this anomaly,we propose the concept of ＂jumping development＂.During jumping development,the center of growth in the bivalve shell jumps forward over a short time interval when the position of the mantle changes.Jumping development explains the unusual structure of the anomalous shell and the development of annual growth lines in typical shells.Annual growth lines are the result of a discontinuity in the shell microstructure induced by jumping development.

关 键 词：bivalves shell microstructure internal growth bands the prismatic layer the nacreous layer 

分 类 号：TS933.23[轻工技术与工程] Q915.817.4[天文地球—古生物学与地层学]