Based on more exquisitely preserved specimens of Markuelia hunanensis recently recovered from Middle and Upper Cambrian in western Hunan and in the light of Synchrotron radiation X-ray tomo-graphic microscopy, the developmental sequence from cleavage through organogenesis to the pre-hatching of Cambrian embryo Markuelia, especially the developmental sequence during the pre-hatching stage, i.e. from the earliest period when the scalids and tail spines only took shape to the latest period (just about hatching), is established. This developmental sequence provides a pattern of embryonic development during the pre-hatching stage, which has not been established in the living scalidophorans (priapulids, loriciferans and kinorhynchs). Thus, it not only enriches our knowledge on the embryonic development of the extant descendants of Markuelia, but also opens a new window to the evolution and development of the animal.
DONG XiPing1,2 1 School of Earth and Space Sciences, Peking University, Beijing 100871, China
在湖南西部中、晚寒武世地层发现了三维保存的精美的软躯体动物化石,即典型的奥斯坦型保存化石(fossils of Orsten-type preservation).描述了Hesslandonasp.(节肢动物门甲壳纲Phosphatocopida目)和Skarasp.(节肢动物门甲壳纲Skaracarida目).简要介绍了奥斯坦型保存化石的科学研究意义,并展望了今后的工作.
