石珊瑚目的早期系统发育和系统分类研究

Advances on the Origin and Early Evolution of Modern Corals

石珊瑚目是中新生代的重要造礁生物。直到中三叠世才大量出现多种石珊瑚化石,距二叠纪末生物大灭绝、古生代皱壁珊瑚和床板珊瑚灭亡14 Ma之久。石珊瑚的起源和早期系统发育,成为生物大灭绝及复苏的一个难题。文章目的是综述多学科研究石珊瑚早期系统发育的进展,以及多家系统分类,展望前景。研究方法有骨骼构造与微细构造及软体的对比,时空分布分析,寻找早期珊瑚化石及分子生物学等。研究结果主要有石珊瑚可能起源于只有软体的海葵类,发现早期石珊瑚化石,以及石珊瑚在300 Ma之前已演化为两支,但还有不少空白和争议。结论是为了查明石珊瑚的早期系统演化和分类,需要加强古生物与今生物学者多学科交叉的综合研究,努力寻找中间环节,填补研究空白。

Scleractinian corals were prominent reef-builders in the Mesozoic and Cenozoic.Their sudden appearance with rich and varied fossils in the Anisian,Middle Triassic was impressive,after the end-Permian mass extinction and a gap of 14 ma in the Early Triassic,when neither rugosan nor scleractinian coral fossils were found.This made the early phylogeny and systematics of the Scleractinian corals dubious and in debate. The object of this paper is to summarize the progress in probing the early phylogeny and systematics of the Order Scleractinia,as well as late discoveries of the Middle Triassic corals.The methods used are coral palaeontology and taxonomic studies of extant corals,i.e.comparison of skeletal structure,microstructure and soft body,search for early coral fossils,as well as molecular biology or molecular systematics.The most interesting results are： the hypothesis that the Scleractinian corals may have ascended from soft-bodied ancestors and that molecular data indicate two main phylogenetic lineages of scleractinians diverged about 300 Ma ago,in the Late Carboniferous,as well as new discoveries of the Anisian corals in China and in North America.With abundant fossil and extant representatives,and thus the necessity to synthesize three very different areas of scientific endeavor,there are many gaps and debates left in this field.The conclusion is that paleontologists and zoologists need to further coordinate their efforts to search for lost links and to bridge the gaps,in the study of the origin and early phylogeny of the Scleractinia.