The palaeobiological significance of clustering in acritarchs: a case study from the early Cambrian of North Greenland

Aggregated clusters of acritarchs are relatively common among assemblages of organic-walled microfossils, yet such associations have received relatively little attention. Here we report a new diversity of acritarch clusters from the early Cambrian Buen Formation of North Greenland. The aggregation patterns of four genera (Skiagia, Comasphaeridium, Asteridium, and Synsphaeridium) are described together with their background population characteristics (presence of openings, inner bodies, and overall disparity) in order to better understand the palaeobiology of these acritarchs. The majority of Skiagia clusters were found to be monospecific despite significant intraspecific variability, a pattern that is suggestive of a strong environmental influence on Skiagia morphologies and aggregation habits. Abundant small (< 20 µm) Comasphaeridium vesicles were recovered in a broad range of chiefly monospecific clusters that have likely been formed under bloom conditions. A colonial habit is tent..., Acritarchs were measured and counted based on palynological slides prepared by Vidal and Peel (1993). The material was collected by John S. Peel on 16th June 1974 and processed using a standard acid maceration procedure (Vidal 1988). Measurements were performed using the software ImageJ.
The statistical significance of correlations was calculated using Spearman’s rank-based correlation coefficient rs (Press et al. 1992), a non-parametric alternative to Pearson’s r. Rs and p values were obtained using the software package PAST (Hammer and Harper 2006).

HAMMER, Ø. and HARPER, D. A. T. 2006. Paleontological data analysis. Blackwell, Oxford, 351 pp.
PRESS, W. H., TEUKOLSKY, S. A., VETTERLING, W. T. and FLANNERY, B. P. 1992. Numerical recipes in C. Cambridge University Press, Cambridge, 994 pp.
VIDAL, G. 1988. A palynological preparation method. Palynology, 12, 215–220.
VIDAL, G. and PEEL, J. S. 1993. Acritarchs from the Lower Cambrian Buen Formation in North Greenland. Bulletin Grønlands ..., , # Data from: The palaeobiological significance of clustering in acritarchs: a case study from the early Cambrian of North Greenland

[https://doi.org/10.5061/dryad.t4b8gtj90](https://doi.org/10.5061/dryad.t4b8gtj90)

This tabular data consists of measurements and counts of acritarch specimens made on palynological slides forming the basis of the paper \"The palaeobiological significance of clustering in acritarchs: a case study from the early Cambrian of North Greenland\". Two additional files consist of correlation statistics obtained from the specimen counts of the acritarch taxon Skiagia. These values were calculated using the software package PAST.

## Description of the data and file structure

Below is a list of file names with their associated descriptions.

\"Synsphaeridium_list\": list of recovered Synsphaeridium specimens and their characteristics. From left to right, coloumns refer to: the name of the photographed specimen; the arrangement of vesicles within the cluster; the numb...

疑源类（acritarchs）的聚集团块在有机壁微体化石组合中较为常见，但此类关联类群迄今尚未得到足够关注。本文报道了采自北格陵兰早寒武世布恩组（Buen Formation）的一类新型疑源类集群多样性。本文描述了4个属（Skiagia、Comasphaeridium、Asteridium及Synsphaeridium）的聚集模式，并结合其背景种群特征（开口结构存在性、内部体及整体形态分异度）展开分析，以期更深入地理解这些疑源类的古生物习性。
研究发现，尽管存在显著的种内变异，绝大多数Skiagia集群均为单种集群，这一模式暗示环境因素对Skiagia的形态特征及聚集行为具有强烈影响。大量小型（<20 μm）Comasphaeridium囊体以多种单种集群形式被发现，此类集群大概率形成于藻华条件下，其集群生活习性尚待进一步验证……
本研究中的疑源类标本基于Vidal与Peel（1993）制备的孢粉玻片进行测量与计数。标本由John S. Peel于1974年6月16日采集，并通过标准酸浸处理流程（Vidal 1988）进行前处理。测量工作采用ImageJ软件完成。
相关性的统计学显著性通过斯皮尔曼等级相关系数rs（Press et al. 1992）计算，该方法为皮尔逊r的非参数替代方案。rs值与p值通过PAST软件包（Hammer与Harper 2006）获取。

### 参考文献
1. HAMMER, Ø. 及 HARPER, D. A. T. 2006. 《古生物学数据分析》. Blackwell出版社, 牛津, 共351页.
2. PRESS, W. H., TEUKOLSKY, S. A., VETTERLING, W. T. 及 FLANNERY, B. P. 1992. 《C语言数值计算程序》. 剑桥大学出版社, 剑桥, 共994页.
3. VIDAL, G. 1988. 孢粉制样方法. 《Palynology》, 12卷, 215–220页.
4. VIDAL, G. 及 PEEL, J. S. 1993. 北格陵兰下寒武统布恩组的疑源类. 《Bulletin Grønlands ...》（原文未完整刊载）.

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## 数据来源：《疑源类集群的古生物学意义：以北格陵兰早寒武世地层为例》
[https://doi.org/10.5061/dryad.t4b8gtj90](https://doi.org/10.5061/dryad.t4b8gtj90)

本表格数据包含基于孢粉玻片的疑源类标本测量与计数结果，为上述论文的核心支撑数据。另有两份附加文件包含基于疑源类类群Skiagia标本计数得到的相关统计数据，统计工作通过PAST软件包完成。

### 数据与文件结构说明
以下为文件名及其对应说明清单：
* "Synsphaeridium_list"：已发现的Synsphaeridium标本清单及其特征。列依次为：拍摄标本的编号；集群内囊体的排列方式；标本数量……