Cellular and Subcellular Structure of Neoproterozoic Animal Embryos

  title={Cellular and Subcellular Structure of Neoproterozoic Animal Embryos},
  author={James W. Hagadorn and Shuhai Xiao and Philip C. J. Donoghue and Stefan Bengtson and Neil J. Gostling and Maria M. Pawlowska and Elizabeth C. Raff and Rudolf A. Raff and F. Rudolf Turner and Yin Chongyu and Chuanming Zhou and Xunlai Yuan and Matthew B McFeely and Marco Stampanoni and Kenneth H. Nealson},
  pages={291 - 294}
Stereoblastic embryos from the Doushantuo Formation of China exhibit occasional asynchronous cell division, with diminishing blastomere volume as cleavage proceeded. Asynchronous cell division is common in modern embryos, implying that sophisticated mechanisms for differential cell division timing and embryonic cell lineage differentiation evolved before 551 million years ago. Subcellular structures akin to organelles, coated yolk granules, or lipid vesicles occur in these embryos. Paired… 
Cell differentiation and germ–soma separation in Ediacaran animal embryo-like fossils
It is concluded that an affinity with cellularly differentiated multicellular eukaryotes, including stem-group animals or algae, is likely but more data is needed to constrain further the exact phylogenetic affinity of the Doushantuo fossils.
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.
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.
Embryo fossilization is a biological process mediated by microbial biofilms
It is shown how fossilization of soft tissues in sediments can be mediated by bacterial replacement and mineralization, providing a foundation for experimentally creating biofilms from defined microbial species to model fossilization as a biological process.
The Multiple Origins of Complex Multicellularity
Proliferation of gene families for transcription factors and cell signals accompany the key functional innovation of complex multicellular clades: differentiated cells and tissues for the bulk transport of oxygen, nutrients, and molecular signals that enable organisms to circumvent the physical limitations of diffusion.
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.
Ultrastructure and in-situ chemical characterization of intracellular granules of embryo-like fossils from the early Ediacaran Weng’an biota
Embryo-like fossils from the early Ediacaran Weng’an biota provide a window of exceptional fossil preservation onto the period of life history in which molecular clocks estimate the fundamental


Mitotic topologies and mechanics of Neoproterozoic algae and animal embryos
  • S. Xiao
  • Environmental Science, Biology
  • 2002
The presence/absence of rigid cell walls and different cytokinetic mechanisms, coupled with mechanics at mitotic offsets, contribute to the diverging mitotic topologies in Doushantuo algae and animal embryos.
Phosphatized Polar Lobe-Forming Embryos from the Precambrian of Southwest China
Fossil embryos similar to modern lobeforming embryos are recognized from the Precambrian Doushantuo Formation phosphates, Weng'an, Guizhou Province, China and imply that lobe formation is an evolutionarily ancient process of embryonic specification.
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.
Embryogenesis and metamorphosis in a haplosclerid demosponge: gastrulation and transdifferentiation of larval ciliated cells to choanocytes
The development of the flagellated choanocytes and other cells in the juvenile from the monociliated outer layer of this sponge's larva is interpreted as the dedifferentiation of fully differentiated larval cells-a process seen during the metamorphosis of other ciliated invertebrate larvae-not as inversion of the primary germ layers.
Experimental taphonomy shows the feasibility of fossil embryos.
Experimental taphonomy of marine embryos and larvae similar in size and inferred cleavage mode to presumptive fossil embryos is reported to provide a predictive basis for interpreting the fossil record to unravel the evolution of ontogeny in the origin of metazoans.
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.
Synchrotron X-ray tomographic microscopy of fossil embryos
SRXTM provides a method of non-invasive analysis that rivals the resolution achieved even by destructive methods, probing the very limits of fossilization and providing insight into embryology during the emergence of metazoan phyla.
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.
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 Eukaryotic Organisms: A Reassessment of the Evidence
It is found that the entire range of morphologic variation exhibited by a dozen taxa of coccoid algae from the Ellery Creek locality of the Bitter Springs formation could be duplicated in detail by partially degrading a unialgal culture of the chroococcalean species Chroococcus turgidus (KUtz.) Nageli.