Phosphatized Polar Lobe-Forming Embryos from the Precambrian of Southwest China

@article{Chen2006PhosphatizedPL,
  title={Phosphatized Polar Lobe-Forming Embryos from the Precambrian of Southwest China},
  author={Jun‐yuan Chen and David J. Bottjer and Eric H. Davidson and Stephen Q. Dornbos and Xiang Gao and Yong-Hua Yang and CHIA-WEI Li and Gang Li and Xiu-Qiang Wang and Dingchang Xian and Hung‐Jen Wu and Yeukuang Hwu and Paul Tafforeau},
  journal={Science},
  year={2006},
  volume={312},
  pages={1644 - 1646}
}
In developing embryos of some extant spiralian animals, polar lobe formation is one of the symmetry-breaking mechanisms for segregation of maternal cytoplasmic substances to certain blastomeres and not others. Polar lobe formation leads to unique early cleavage morphologies that include trilobed, J-shaped, and five-lobed structures. Fossil embryos similar to modern lobeforming embryos are recognized from the Precambrian Doushantuo Formation phosphates, Weng'an, Guizhou Province, China. These… 

Cellular and Subcellular Structure of Neoproterozoic Animal Embryos

Stereoblastic embryos from the Doushantuo Formation of China exhibit occasional asynchronous cell division, with diminishing blastomere volume as cleavage proceeded, implying that sophisticated mechanisms for differential cell division timing and embryonic cell lineage differentiation evolved before 551 million years ago.

Complex embryos displaying bilaterian characters from Precambrian Doushantuo phosphate deposits, Weng'an, Guizhou, China

These embryos provide further evidence for the presence of bilaterian animals in the Doushantuo biota and indicate that the last common ancestor of the bilaterians lived much earlier than is usually thought.

Fossilized Nuclei and Germination Structures Identify Ediacaran “Animal Embryos” as Encysting Protists

It is demonstrated using synchrotron-based x-ray tomographic microscopy that the fossils have features incompatible with multicellular metazoan embryos, which represent an evolutionary grade in which palintomic cleavage served the function of producing propagules for dispersion.

Sipuncula: an emerging model of spiralian development and evolution.

With the unsegmented Sipuncula now repositioned within the segmented Annelida, sipunculan worms have become timely and appropriate models for investigating the potential for flexibility in spiralian development, including segmentation.

The origin of intracellular structures in Ediacaran metazoan embryos

These findings suggest that, while the Doushantuo intracellular structures may occupy the same topological position as strongly degraded nuclei and vesicles, they do not represent organelles with intact enclosing membranes, critically undermining recent hypotheses about the nature of nuclear division.

Fossil embryos deep in the fossil record

Embryos have been found in ‘old’ rocks on four continents, especially in Siberia, Nevada, Australia and China. They have been discovered in sedimentary rocks of even Late Neoproterozoic age, assuming

Cambrian Fossil Embryos from Western Hunan, South China

The exquisitely preserved fossil embryos of Markuelia recovered from the limestones of the Middle Cambrian Haoqiao Formation and Upper Cambrian Bitiao formation in western Hunan, South China are

Diverse and complex developmental mechanisms of early Ediacaran embryo-like fossils from the Weng'an Biota, southwest China

Contrary to the prevailing view, the results together with recent studies suggest that the diversity and complexity of developmental mechanisms documented by the EELFs are much higher than is often claimed.
...

References

SHOWING 1-10 OF 24 REFERENCES

Precambrian animal diversity: putative phosphatized embryos from the Doushantuo Formation of China.

Putative fossil embryos and larvae from the Precambrian phosphorite rocks of the Doushantuo Formation in Southwest China have been examined in thin section and identified what appear to be modern cnidarian developmental stages, including both anthozoan planula larvae and hydrozoan embryos.

Three-dimensional preservation of algae and animal embryos in a Neoproterozoic phosphorite

Embryos preserved in early cleavage stages indicate that the divergence of lineages leading to bilaterians may have occurred well before their macroscopic traces or body fossils appear in the geological record.

Determinative development in the polyclad turbellarian, Hoploplana inquilina

The results demonstrate that the polyclad embryo is determined early in development, though significant cell interactions occur during cleavage, and suggest that determinative development and quartet spiral cleavage are always associated and probabilistically associated.

PHOSPHATIZED ANIMAL EMBRYOS FROM THE NEOPROTEROZOIC DOUSHANTUO FORMATION AT WENG'AN, GUIZHOU, SOUTH CHINA

Phosphorites of the uppermost Neoproterozoic Doushantuo Formation exposed at Weng'an, South China, contain globular microfossils characterized by distinctively sculpted outer coverings and precise patterns of cell division, which support their reinterpretation as the eggs and embryos of early animals.

Origins of Mosaic Development?: Zygote Surface Differentiation During Meiosis in the Polyclad Flatworm Hoploplana

Summary Changes in egg shape and surface morphology during maturation may be related to the localization of cytoplasmic determinants in the embryos of organisms with spiral cleavage. The eggs of the

Precambrian animal life: probable developmental and adult cnidarian forms from Southwest China.

The new observations reported in this paper indicate the existence of a diverse and already differentiated cnidarian fauna, long before the Cambrian evolutionary event.

Precambrian sponges with cellular structures

The fauna indicates that animals lived 40 to 50 million years before the Cambrian Explosion, and the presence of possible amphiblastula larva suggests that the calcareous sponges may have an extended history in the Late Precambrian.

Small Bilaterian Fossils from 40 to 55 Million Years Before the Cambrian

Ten phosphatized specimens of a small animal displaying clear bilaterian features have been recovered from the Doushantuo Formation, China, and provide the first evidence confirming the phylogenetic inference that Bilateria arose well before the Cambrian.

MICROFILAMENTS IN THE POLAR LOBE CONSTRICTION OF FERTILIZED EGGS OF ILYANASSA OBSOLETA

This paper presents a new probabilistic analysis of the response of the immune system to the presence of Representative Tournaisian coronavirus, a type of tick which can be fatal to animals and humans.

Eumetazoan fossils in terminal proterozoic phosphorites?

  • S. XiaoX. YuanA. Knoll
  • Geography, Environmental Science
    Proceedings of the National Academy of Sciences of the United States of America
  • 2000
Evidence for Doushantuo eumetazoans is provided by millimeter-scale tubes that display tabulation and apical budding characteristic of some Cnidaria, especially the extinct tabulates.