Damesellidae科(三叶虫)演化及中、上寒武统界线

EVOLUTION OF THE FAMILY DAMESELLIDAE (TRILOBITA) AND BOUNDARY BETWEEN THE MIDDLE AND UPPER CAMBRIAN

本文将Damesellidae科分作5个亚科(含2个新亚科——Blackwelderinae亚科和Teinis-tininae亚科),系统讨论了科内的演化,划分出3个发展阶段(初始阶段,繁盛阶段和特化阶段)。并从Damesellidae科演化特点提出传统中、上寒武统界线的弊端,建议以G.r.a.带与G.r.r.带之间的界线代之。

The Damesellidae is divided into 5 subfamilies, including 2 new subfamilies, Black-welderinae and Teinistioninae. Evolution within the family Damesellidae is discussed, and 3 stages of development are established: primary stage, flourishing stage and specializing stage. Moreover, the paper indicates some shortcomings about the traditional boundary (Lejopyge laevigata Z. / Agnostus pisiformis Z. ) between the Middle and Upper Cambrian and suggests that it should be replaced with a new boundary (Glyptagnostus reticulatus an-gelini Z. / Glyptagnostus reticulatus reticulatus Z. ).