华南法门期牙形刺的辐射

F／F牙形刺灭绝事件以后，牙形刺很快进入复苏期（王成源、Ziegler，2004）。有关法门期牙形刺的辐射，在国内外的文献中还没有详细的论述或论证。本文基于以前对广西桂林垌村和龙门剖面的牙形刺集群灭绝与复苏的研究，2003年又在垌村剖面加密采样，重点是研究F／F事件后，牙形刺由复苏到辐射阶段的特征，探索牙形刺何时和如何由复苏期进化到辐射期。本文的材料主要是依据华南的资料，特别是本文作者研究多年的垌村剖面的资料。牙形刺的灭绝与复苏是以法门期最主要的属Palmatolepis为主线，在种一级的水平上确定的。法门期牙形刺的辐射同样是以Palmatolepis属内种一级的水平上讨论的。同时也涉及到其它属。本文首次明确提出：牙形刺在晚triangularis带就进入辐射期，因为正是从晚triangularis带，Palmatolepis的minuta，werneri，sandbergi，perlobata，cf．regularis，subperlobata，tenupunctata7个重要种群开始出现，并在法门期中期达到辐射期的高峰。

RADIATION OF DEVONIAN FAMENNIAN CONODONTS IN SOUTH CHINA

Conodont mass extiction occurred stepwise in the latest Frasnian (late linguiformis Zone) and was of very short time span and on a global scale. Conodont recovery occurrence of Palmatolepis triangularis. The time span of the conodont recovery interval can be estimated as much less than 0.5m.y. An independent survival interval cannot be determined. All of the early and middle triangularis Zone should be assigned to the recovery interval, in which conodont recovered also in astepwise pattern and on a global scale.The study of conodont mass extinction and recovery is based on the materials from South China, especially from the Dongcun and Longmen sections in Guilin, and mainly at the species level of Palmatolepis. The study of Famennian conodont radiation is mainly based on the Dongcun section in Guilin, Guangxi, and also at the species level of Palmatolepis.The present author first proposes in this paper that Famennian conodont radiation interval began in the Late triangularis Zone rather than in the middle of the Middle triangularis Zone as Sandbert et al. (2002) proposed. It was indicated by the first occurences of seven palmatolepid taxa, i.e. (Text-figs.1,2)The taxonomic radiation interval reached itspeack in latecrepida-rhomboidea-marginiferazones .But after the peak,number of taxa declinedstep by step intrachytera-postera-expansa-prae-sulcatazones ,and at the latepraesulcataZone on-ly one subspecies left ,that isPal. gracilis graci-lis. At the end of Devonian,all species ofPalma-tolepisare extinct (Text-fig.3) .