Biological affinity, phenotypic variation and palaeoecology of Tetradium Dana, 1846
Biological affinity, phenotypic variation and palaeoecology of Tetradium Dana, 1846
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DOI：
10.1111/j.1502-3931.2009.00151.x
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发表时间：
2009-12
期刊：
影响因子：
1.5
通讯作者：
H. M. Steele-petrovich
中科院分区：
文献类型：
--
作者：
H. M. Steele-petrovich
将奥陶纪化石Tetradium Dana（1846年）的形态和生活方式与毛藻海绵、平板珊瑚和近代红藻进行比较，发现Tetradium的几个定义特征与其毛藻和平板分类不相容。所有的Tetradium特征适合红藻鉴定，然而，作为一个钙化的单轴皮质的花植物。有人认为，从功能形态的基本subsquare横截面的Tetradium管是一个适应紧密包装，这意味着基本的生长形式是紧凑的，应该有发展的条件是最佳的。更开放的形式是从它衍生出来的，可能占据了不太有利的环境。加拿大渥太华河谷的古生态学研究表明，Tetradium的生长形式与环境胁迫有关，随着盐度的增加而变得更加开放，即紧凑的T.在正常的海洋环境中，T. cellulosum管和单根T.高盐度下的类棘孔菌管。研究区不同的Tetradium生长形式是单一种的表型变异，而不是不同的种和属。因此，仅根据生长形式将Tetradium划分为不同种和属的分类没有生物学基础。很少有证据表明种间相互作用与Tetradium。
Comparisons of morphologies and modes of life of the Ordovician fossil Tetradium Dana, 1846, with chaetetid sponges, tabulate corals, and Recent rhodophytes show that several defining Tetradium characteristics are incompatible with its chaetetid and tabulate classifications. All Tetradium characteristics fit a rhodophyte identification, however, as a calcified uniaxial corticated florideophyte. It is argued from functional morphology that the fundamental subsquare cross-section of the Tetradium tube is an adaptation for close packing, which implies that the basic growth form is compact and should have developed where conditions were optimal. More open forms are derived from it and probably occupied less-favourable environments. Palaeoecological studies from the Ottawa Valley, Canada, show that the Tetradium growth form is correlated with environmental stress and became more open as salinity increased: i.e. the compact T. fibratum form lived in normal marine conditions, radiating bundles of T. cellulosum tubes in low to middle hypersalinity and single T. syringoporoides tubes in high hypersalinity. Different Tetradium growth forms from the study area are phenotypic variants of a single species, rather than different species and genera. Therefore, classifications that divide Tetradium into different species and genera based only on growth form have no biological basis. There is little evidence of interspecific interactions with Tetradium.