Data from: Morphometrics and paleoecology of Catenipora (Tabulata) from Xiazhen Formation (Upper Ordovician), Zhuzhai, South China

Catenipora is one of the most common tabulate coral genera occurring in various lithofacies in the Upper Ordovician Xiazhen Formation at Zhuzhai in South China. A combination of traditional multivariate analysis and geometric morphometrics is applied to a large number of specimens to distinguish and identify species. Based on three major principal components extracted from 11 morphological characters, three major groups as determined by the cluster-analysis dendrogram are considered to be morphospecies. Their validity and distinctiveness are confirmed by discriminant analysis, descriptive statistics, and bivariate plots. Tabularium area and common wall thickness are the most meaningful characters to distinguish the three morphospecies. Geometric morphometrics is adopted to compare the morphospecies with types and/or figured specimens of species previously reported from the vicinity of Zhuzhai. Despite discrepancies in corallite size, principal component analysis and discriminant analysis, as well as consideration of overall morphological characteristics, indicate that the morphospecies represent C. zhejiangensis Yu in Yu et al., 1963, C. shiyangensis Lin and Chow, 1977, and C. dianbiancunensis Lin and Chow, 1977. Catenipora occurs in seven stratigraphic intervals in the Xiazhen Formation at Zhuzhai, representing a variety of heterogeneous environments. The coralla preservation is variable due to differential compaction; coralla preserved in limestones are commonly intact and in growth position, whereas those in shales are mostly crushed or fragmentary. The size and shape of corallites are considered primarily to be species-specific characters, but are also related to the depositional environments. In all species, morphological characters including corallite size, septal development, and shape and size of lacunae show high variability in accordance with lithofacies and stratigraphic position. The intraspecific differences in corallite size at various localities in the Zhuzhai area may indicate responses to local environmental factors, but may also reflect genetic differences if there was limited connection among populations.

链珊瑚属（Catenipora）是华南竹寨地区晚奥陶世下镇组中最为常见的床板珊瑚（tabulate coral）属之一，广泛出现于该地层的多种岩相之中。本研究结合传统多元分析（multivariate analysis）与几何形态测量学（geometric morphometrics），对大量标本开展物种区分与鉴定工作。基于从11个形态特征中提取的3个主成分，结合聚类分析树状图（cluster-analysis dendrogram）所确定的3个主要类群，被认定为形态种（morphospecies）。判别分析（discriminant analysis）、描述性统计（descriptive statistics）与双变量图（bivariate plots）均证实了这些形态种的有效性与独特性，其中横板区域面积与共壁厚度是区分这3个形态种的最具区分意义的特征。本研究采用几何形态测量学方法，将上述形态种与此前在竹寨周边报道过的物种的模式标本及/或图解标本进行比对。尽管珊瑚个体（corallites）尺寸存在差异，但主成分分析、判别分析以及对整体形态特征的综合考量均表明，这些形态种分别对应于C. zhejiangensis Yu in Yu et al., 1963、C. shiyangensis Lin and Chow, 1977以及C. dianbiancunensis Lin and Chow, 1977。链珊瑚属在竹寨地区下镇组的7个地层间隔（stratigraphic intervals）中均有产出，代表了多种异质沉积环境。珊瑚体的保存状态存在显著差异，这源于差异压实作用（differential compaction）：保存在灰岩中的珊瑚体通常完整且处于生长原位，而保存在页岩中的珊瑚体则多被压碎或呈碎片状。珊瑚个体的大小与形态主要为物种特异性特征，但同时也与沉积环境存在关联。在所有物种中，包括珊瑚个体尺寸、隔壁发育程度（septal development）以及珊瑚间隙（lacunae）的形态与大小在内的形态特征，均随岩相和地层位置呈现出较高的变异性。竹寨地区不同产地的珊瑚个体尺寸存在种内差异（intraspecific differences），这可能反映了类群对当地环境因子的响应，但如果种群（populations）间存在有限的基因交流，该差异也可能体现了遗传分化。