Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott
Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott
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DOI：
10.1073/pnas.0405867102
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发表时间：
2005-02-01
影响因子：
11.1
通讯作者：
Butterfield, NJ
中科院分区：
文献类型：
--
作者：
Botting, JP;Butterfield, NJ
海绵类别之间的关系存在争议，特别是钙质海绵和硅质海绵之间的关系。来自伯吉斯页岩的推定的球状埃菲利亚球沃尔科特 (Eiffelia globosa Walcott) 标本显示，骨骼网格中存在诊断性六线虫针状体。艾菲尔属中这些针状体的排列被证明与早期的原海绵状六行线虫的排列完全相同，并且海绵的生长通过相同的模式发生，从而产生相同的骨骼体形态。这些类别的针状成分的差异是通过对艾菲尔属的埋藏学特征的观察来解释的，这些特征表明针状内至少存在两个矿物学上不同的层。这些结果支持了分子分析，将钙质-硅海绵转变确定为最早的主要海绵分支，并表明异质海绵动物与六线海绵动物是并系的。
The relationships of the sponge classes are controversial, particularly between the calcareous and siliceous sponges. Specimens of the putative calcarean Eiffelia globosa Walcott from the Burgess Shale show the presence of diagnostic hexactinellid spicules integrated into the skeletal mesh. The arrangement of these spicules in Eiffelia is shown to be precisely equivalent to that of early protospongioid hexactinellids, and sponge growth occurred through an identical pattern to produce identical skeletal body morphology. The difference in spicule composition of the classes is interpreted through the observation of taphonomic features of Eiffelia that suggest the presence of at least two mineralogically distinct layers within the spicules. These results support molecular analyses that identify the calcarean-silicisponge transition as the earliest major sponge branch and suggest that the heteractinids were paraphyletic with respect to the Hexactinellida.