Data from: Morphometrics and paleoecology of Catenipora (Tabulata) from the 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）是华南竹寨地区上奥陶统下镇组不同岩相中最为常见的床板珊瑚属之一。本研究结合传统多元分析与几何形态测量学（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确定的3个主要类群，被认定为形态种。判别分析、描述统计与二元绘图均验证了这3个形态种的有效性与区分度，其中床板室面积与共壁厚度是区分这3个形态种的最具辨识度的形态特征。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的物种的模式标本及已图示标本进行比对。尽管珊瑚单体尺寸存在差异，但主成分分析、判别分析结果结合整体形态特征表明，这些形态种分别对应1963年Yu等发表的浙江链珊瑚（C. zhejiangensis Yu in Yu et al., 1963）、1977年Lin与Chow发表的石羊链珊瑚（C. shiyangensis Lin and Chow, 1977）以及滇边村链珊瑚（C. dianbiancunensis Lin and Chow, 1977）。竹寨地区下镇组的链珊瑚属化石共产出自7个地层区间，代表了多样的异质沉积环境。珊瑚体的保存状况因差异压实作用而存在差异：产出于石灰岩中的珊瑚体通常完整且保持生长原位，而页岩中的珊瑚体则多被压碎或呈碎片状。珊瑚单体的大小与形态主要为种特异性特征，但同时也与沉积环境相关。在所有物种中，珊瑚单体尺寸、隔壁发育情况以及间隙的形态与大小等形态特征，均随岩相和地层位置呈现出显著变异。竹寨地区不同产地的珊瑚单体尺寸存在种内差异，这可能反映了生物对当地环境因子的响应，但若种群间存在有限的基因交流，也可能体现了遗传分化。