The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms

The loss of information resulting from taphonomic degradation could represent a significant bias in the study of morphological diversity. This potential bias is even more concerning given the uneven effect of taphonomy across taxonomic groups, depositional facies, and stratigraphic successions and in response to secular changes through the Phanerozoic. The effect of taphonomic degradation is examined using character-based morphological data sets describing disparity in Paleozoic crinoids and blastozoans. Characters were sequentially excluded from the analyses following progressive taphonomic loss to determine how morphologic metrics, such as the relative distribution of taxa in morphospace and partial disparity, changed with increasing taphonomic alteration. Blastozoans showed very little change in these metrics with decreasing preservational quality, which is a result of characters that create distance in morphospace being recognizable in isolated plates. The opposite result is present...

埋藏劣化（taphonomic degradation）所引发的信息丢失，可能会对形态多样性研究造成显著偏差。鉴于埋藏学在不同分类群、沉积相及地层序列间的作用存在不均一性，且其效应会随显生宙（Phanerozoic）期间的长期时间尺度变化发生改变，这一潜在偏差更值得警惕。本研究采用基于性状的形态数据集（character-based morphological data sets），针对古生代海百合（Paleozoic crinoids）与海蕾类（blastozoans）的形态差异度展开分析，以探究埋藏劣化的影响。研究中通过逐步移除性状以模拟渐进式埋藏信息丢失，以此探明各类形态学指标——如类群在形态空间（morphospace）中的相对分布及部分差异度（partial disparity）——如何随埋藏劣化程度的加剧发生变化。海蕾类的上述指标随保存质量下降仅出现极微小变化，这是因为构建形态空间距离的性状在分离骨板（isolated plates）中仍可被识别。而与之相反的结果则见于……