Some Middle Paleozoic Conulariids (Cnidaria) as Possible Examples of Taphonomic Artifacts
Some Middle Paleozoic Conulariids (Cnidaria) as Possible Examples of Taphonomic Artifacts
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发表时间：
2003
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通讯作者：
M. Simões;S. Rodrigues;J. Leme;H. V. Iten
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作者：
M. Simões;S. Rodrigues;J. Leme;H. V. Iten
锥虫提供了很好的例子，生物特征和其他字符已被用来诊断化石物种可以受到影响的埋藏过程，可能导致勃起的埋藏分类，或埋藏文物。基于对巴西南部泥盆纪蓬塔格罗萨的Conularia quichua Ulrich的埋藏学分析，我们认为，在使用生物特征和其他特征来诊断conulariid物种时必须谨慎。例如，横肋间距的测量必须校正平行于其长轴的囊的压实。C.与层理成高角度的基丘亚岩几乎总是表现出这种变形，如果不进行校正，会导致大量额外的测量误差。同样，C.克丘亚语在压缩和未压缩的标本之间存在差异，因此很难以高度的一致性和可重复性来测量这种特性。用于诊断锥虫的其他特征（横肋的几何形状，存在或不存在间隙脊和节点）易受风化的修改和信息丢失。在回顾已发表的其他锥虫类的描述时，我们发现某些物种可能是塔布分类群。未来对新物种的描述应该基于包括已知的物种分布模式的收集。此外，新的conulariid类群的竖立应尽可能基于完整或接近完整的标本，形态比较应使用标本显示类似的模式保存。
Conulariids provide good examples of how biometric and other characters that have been used to diagnose fossil species can be affected by taphonomic processes, possibly leading to the erection of taphonomic taxa, or taphonomic artifacts. Based on analysis of the taphonomy of Conularia quichua Ulrich from the Devonian Ponta Grossa of southern Brazil, we argue that caution must be exercised when using biometric and other characters to diagnose conulariid species. For example, measurements of the spacing of the transverse ribs must be corrected for compaction of the theca parallel to its long axis. C. Quichua oriented at high angles to bedding almost always exhibit this kind of deformation, which if not corrected for results in substantial additional measurement error. Similarly, the value of the apical angle of C. Quichua differs between compressed and uncompressed specimens, making it difficult to measure this character with a high degree of consistency and reproducibility. Other characters (geometry of the transverse ribs, presence or absence of interspace ridges and nodes) used to diagnose conulariids are susceptible to modification and information loss through weathering. In reviewing published descriptions of other conulariids, we have found that certain species may be taphotaxa. Future descriptions of new species should be based on collections encompassing the known spectrum of preservational patterns. Also, the erection of new conulariid taxa should be based as much as possible on complete or nearly complete specimens, and morphometric comparisons should be made using specimens showing similar patterns of preservation.