Diversity of photo-symbiotic bivalves and modeling of their diversification

光共生双壳类的多样性及其多样化建模

• 批准号: 05454003
• 负责人: OHNO Terufumi
• 金额: $ 2.37万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05454003/
• 关键词: algae; bivalve; loochooanum; Fragum; fragum; Symbiodinium; symbiosis; unedo; 渦鞭毛藻; 暗所適応; モクハチアオイ; 共生関係; ヒップリテス上科; 機能形態学; 古生態学; 光共生; チッソ代謝活性; 光合成活性; PCP

Bivalves with symbiotic zooxanthella (photo-symbiotic bivalves) have been known since detailed study by Yonge (1936). These occur amongst genera of Tridacna (Yonge 1936), Hippopus (Yonge 1936) and Corculum (Kawaguti 1941) , all of which are Indo-Pacific tropical shallow water dwellers (for an illustration of representative photo-symbiotic bivalves.All the known photo-symbiotic bivalves belong to the superfamies Cardiacea and Tridacnacea which are closely related to each other. The majority of the bivaives of the superfamily cardiacea adopts an infaunal mode of life. Thus the ancestors of the photo-symbiotic bivalves mentioned above were most likely infaunal bivalves . This raises the question how the symbiotic relationship originated between the infaunal ancestors of these bivalves and the light-demanding photosynthetic zooxanthellae?Our invesitgation revealed the following points. Photo-symbiotic Fragum fragum and Fragum loochooanum burrow completely in sediments and supply light thro … More ugh a posterior shell gape to zooxanthellae of their internal soft parts. This new mode of bivalve's photo-symbiosis can be termed as sciaphilous (shade loving) , while the hitherto known one as heliophilous (sun loving), in which bivalves expose mantles or transparent shells out of sediments to harvest light. Presently examined Fragum unedo is heliophilous. Sciaphilous photo-symbiosis of F.fragum is enabled by the zooxanthellae's ability to begin photosynthesis at light intensity (50 m-Einstein m-2s-1) by far lower than the ambient light intensity of their habitat.Thus the zooxanthellae's preadaptation to low Hght intensity might have playd an important role in originating algal-bivalve symbiosis. Sciaphilous photo-symbiosis allows bivalves to enjoy profit of photo-symbiosis without risking predation or epibiont attachment, thus may have been popular among fossil photo-symbiotic bivalves. The disproportionately rapid increase in the length of posterior shell gape and the very rapid decrease of the angle between posterior and ventral valve margins during the growth of two sciaphilous Fragum species, which ensure zooxanthellae's effective light harvesting, can be used as criteria in searching for fossil sciaphilous algal-bivalve photo-symbiosis. Less

自从Yonge(1936)详细研究以来，具有共生虫黄杆菌的双壳类(光共生双壳类)已被发现。这些都发生在Tridacna(Yonge 1936)，Hippopus(Yonge 1936)和Corculum(Kawaguti 1941)属中，这些属都是印度-太平洋热带浅水生物(为了说明典型的光共生双壳类)。所有已知的光共生双壳类都属于相互密切联系的心脏科和Tridacnacea亚科。大多数超家族的生物采取了一种非动物性的生活方式。因此，上面提到的光共生双壳类的祖先很可能是非动物群的双壳类。这就提出了这样一个问题：这些双壳类的非动物群祖先与光合作用的虫黄藻之间的共生关系是如何产生的？我们的研究揭示了以下几点。光共生碎屑和丝瓜完全在沉积物中挖洞并通过…提供光线更多的是，它们内部柔软的部分有一个后壳开口到虫黄。这种新的双壳类光生共生模式可以被称为嗜坐性(喜欢遮荫)，而迄今所知的模式是嗜日性(喜好阳光)，双壳类露出沉积物中的外套或透明贝壳以获取阳光。目前检查的Fragum unedo是嗜日性的。碎片藻的亲水性光共生是由于虫黄藻在远低于其栖息地环境光强的光强(50m爱因斯坦m-2s-1)下开始光合作用的能力所致，因此，虫黄藻对低光强的预适应可能在起源藻类-双壳类共生中发挥了重要作用。亲光共生使得双壳类可以享受光生共生的好处，而不会有被捕食或附生的风险，因此可能在化石光生双壳类中很受欢迎。在两个嗜坐性软体动物的生长过程中，后壳间隙长度的不成比例的快速增加和后部瓣膜边缘与腹侧瓣缘夹角的非常迅速的减小，确保了虫黄藻的有效捕光，可以作为寻找化石坐骨性藻类与双壳贝类光生共生的标准。较少

项目成果

Ohno,T.: "Intra-periostracal calcified needles of the bivalve family Veneridae." Proceedings of the 7th International Biomineralization,Monaco,. 1993(印刷中). (1995)

Ohno, T.：“双壳类贝壳内钙化针”，摩纳哥 1993 年第七届国际生物矿化论文集（1995 年出版）。

Terufumi Ohno: "Micro-growth lines in Bivalves." Fossil Research. 27 (japanese). 7-15 (1994)

Terufumi Ohno：“双壳类动物的微生长线。”

Hiroshi Kitazato, Terufumi Ohno and Kazumi Matsuoka: "Revival of fossils - experimental Paleontology." Gekkan Chikyu. vol.15 (japanese). 523-524 (1993)

Hiroshi Kitazato、Terufumi Ohno 和 Kazumi Matsuoka：“化石的复兴 - 实验古生物学。”

大野照文: "二枚貝の生長縞解析の現状" 月刊海洋. 25. 613-621 (1993)

Terufumi Ohno：“双壳类生长条纹分析的现状”月刊 Kaiyo 25. 613-621 (1993)

川上紳一,大野照文: "原生代-古生代境界の地球システム変動と多細胞動物の出現" 地震. 48. 487-508 (1996)

Shinichi Kawakami、Terufumi Ohno：“地球系统变化和元古代-古生代边界多细胞动物的出现”地震 48. 487-508 (1996)。