中国科学院南京地质古生物研究所机构知识库

Although knowledge of exceptional Cambrian fossil Lagerstatten has increased dramatically, relatively little information has been uncovered about the early ontogeny of ancient Metazoa. Here we describe new phosphatized eggs and embryos, partly indicating germ band formation, and the earliest known larvae of early bilaterians. Developmental sequences are reconstructed for Pseudooides- and tetramerous-type embryos. Together with these developmental sequences, patterns of germ band formation, irregular "radial" cleavage types, and unciliated larva with serial divisions and a posterior segment indicate affinities with protostomes, most probably within an ancestral arthropodan lineage.