Earliest known halysitid tabulate coral Catenipora tongchuanensis from the middle of the Jinghe Formation (Sandbian; early Late Ordovician) at Taoqupo, north-central China

　　Catenipora is one of the most common tabulate coral genera in the Upper Ordovician Jinghe and Beiguoshan formations on the southern margin of the Ordos Basin, north-central China.

　　Recently, Dr. LIANG Kun from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his collegues distinguished and identified the species of Catenipora using multivariate morphometric procedures. Cluster analysis based on morphological characters of coralla yields a dendrogram showing five morphospecies. The validity and distinctiveness of the morphospecies are evaluated by discriminant analysis and non-metric multidimensional scaling.

　　To identify the species represented by the morphospecies, type specimens of species that are morphologically similar from north-central China (Sino-Korean Block) and surrounding palaeocontinents are compared with the morphospecies by non-metric multidimensional scaling and descriptive statistics. The result indicates that one morphospecies represents C. daliangensis (Yu), another represents C. subovata Yu, and the others are considered to be new species named C. tongchuanensis, C. jingyangensis and C. tiewadianensis. Catenipora tongchuanensis from the middle of the Jinghe Formation (Sandbian; early Late Ordovician) is the earliest confirmed halysitid tabulate. Species of Catenipora in north-central China (Sino-Korean Block) show the highest morphological diversity (i.e. disparity) in terms of corallite size and shape, compared with other palaeocontinents in China. Species of Catenipora in North Qilian share more common components with those from north-central China than any other palaeocontinent in China.

　　The different morphological characteristics in terms of corallite shape and ranks in some Katian species of Catenipora from East Junggar, Mongolia, South China and Estonia suggest that some species may have originated separately during the Great Ordovician Biodiversification Event, and Catenipora is possibly polyphyletic. 

　　Paper information: Liang, K., Elias, R.J., Lee, D.-J. 2018. The early record of halysitid tabulate corals, and morphometrics of Catenipora from the Ordovician of north-central China. Papers in Palaeontology.