A placozoan affinity for Dickinsonia and the evolution of late Proterozoic metazoan feeding modes

  title={A placozoan affinity for Dickinsonia and the evolution of late Proterozoic metazoan feeding modes},
  author={Erik A. Sperling and Jakob Vinther},
  journal={Evolution \& Development},
Dickinsonia is one of the most recognizable forms in the Ediacaran fauna, but its phylogenetic position has been contentious, and it has been placed in almost every kingdom of life. [] Key Result The affinity with placozoans is evidenced primarily by the unique feeding mode of Dickinsonia, which is demonstrated by a series of feeding traces. These traces indicate that Dickinsonia moved over the Ediacaran matgrounds, and digested the mat using its entire lower sole. The ability of Dickinsonia to move negates…

Highly regulated growth and development of the Ediacara macrofossil Dickinsonia costata

It is shown that development in Dickinsonia costata was surprisingly highly regulated to maintain an ovoid shape via terminal addition and the predictable expansion of modules, suggesting that it does not belong within known animal groups, but that it utilized some of the developmental gene networks of bilaterians.

Ediacaran developmental biology

  • F. DunnA. LiuP. Donoghue
  • Environmental Science, Geography
    Biological reviews of the Cambridge Philosophical Society
  • 2018
It is concluded, based on the available evidence, that the affinities of the rangeomorphs and the dickinsoniomorphs lie within Metazoa.

Ediacaran pre-placozoan diploblasts in the Avalonian biota: the role of chemosynthesis in the evolution of early animal life

It is argued for the presence of a simple, diploblastic body plan in these early animals and the means by which they probably derived nutrients from chemosynthetic bacteria thriving at the sediment–water interface are discussed.

Developmental processes in Ediacara macrofossils

This analysis demonstrates that the genetic pathways for multicellularity, axial polarity, musculature, and a nervous system were likely present in some of these early animals, supporting the hypothesis that these evolved independently in disparate bilaterian clades.

Rheotaxis in the Ediacaran epibenthic organism Parvancorina from South Australia

Taphonomic and morphological evidence suggests that the preferred orientations of Parvancorina individuals are not the result of passive current alignment, but represent a rheotactic response at some stage during their life cycle.


Describing the anomalous preservation of a distinct, prolific, and previously undescribed Ediacaran biogenic sedimentary structure, informally known as “mop,” from the Ediacara Member of the Rawnsley Quartzite in South Australia suggests a shared origin with the holdfast form genus Aspidella and convergence with Pseudorhizostomites.

Dickinsonia costata — the first evidence of neoteny in Ediacaran organisms

The statistical analysis of Dickinsonia imprints from a number of fossil assemblages in the southeastern White Sea shows an existence of two distinct groups that could represent different stages of ontogeny of a single species — D. tenuis and D. costata.

Ancestral state reconstruction of ontogeny supports a bilaterian affinity for Dickinsonia

This study formalizes the connection between ontogeny in Dickinsonia—which grows by the addition of metameric units onto one end of its primary axis—with terminal addition, defined as growth and patterning from a posterior, subtermial growth zone, and concludes that terminal addition is a synapomorphy of bilaterian animals.

The developmental biology of Charnia and the eumetazoan affinity of the Ediacaran rangeomorphs

The development of Charnia masoni is characterized and the affinity of rangeomorphs is established, among the oldest and most enigmatic components of the Ediacaran macrobiota, and homology and rationalize morphogenesis between disparate rangeomorph taxa are found.

Rangeomorphs, Thectardis (Porifera?) and dissolved organic carbon in the Ediacaran oceans

The recognition of sponges in the Mistaken Point biota provides some of the earliest body fossil evidence for this group, which must have ranged through the Ediacaran based on biomarkers, molecular clocks, and their position on the metazoan tree of life, in spite of their sparse macroscopic fossil record.



A Fresh Look at Dickinsonia: Removing It from Vendobionta

This research is not only removing Dickinsonia from Vendobionta, but also bringing the fossil record of ctenophores forward to 20 million years before the Cambrian “explosion”.

Poriferan paraphyly and its implications for Precambrian palaeobiology

It is demonstrated, in accordance with previous molecular studies, that sponges are paraphyletic, and that calcisponge are more closely related to eumetazoans than they are to demosponges.

Field biology of placozoans (Trichoplax): distribution, diversity, biotic interactions.

Greater expanded distributions for known haplotypes and fresh specimens that include a new haplotype are reported, and the evidence that many more almost certainly await discovery is reviewed, to stimulate a broader search for placozoans and a fuller exploration of their distribution, diversity, and all other aspects of their enigmatic lives.

Osmotrophy in modular Ediacara organisms

The results support the viability of osmotrophic feeding in rangeomorphs and erniettomorphs, help explain their taphonomic peculiarities, and point to the possible importance of earliest macroorganisms for cycling dissolved organic carbon that may have been present in abundance during Ediacaran times.

Early origin of the bilaterian developmental toolkit

  • D. Erwin
  • Biology
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2009
It is suggested that placozoans and cnidarians represent a depauperate residue of a once more diverse assemblage of early animals, some of which may be represented in the Ediacaran fauna (c. 585–542 Myr ago).

The phylogenetic position of the comb jellies (Ctenophora) and the importance of taxonomic sampling

The reconstructed topology is considered to represent the current best hypothesis of the interrelationships of these old lineages and morphological features supporting alternative hypotheses are discussed in the light of this result.

The Trichoplax genome and the nature of placozoans

Despite the apparent cellular and organismal simplicity of Trichoplax, its genome encodes a rich array of transcription factor and signalling pathway genes that are typically associated with diverse cell types and developmental processes in eumetazoans, motivating further searches for cryptic cellular complexity and/or as yet unobserved life history stages.

On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota.

Ediacaran biota: The dawn of animal life in the shadow of giant protists

Abstract Functional, constructional, and preservational criteria led to a reinterpretation of seemingly complex trace fossils and the majority of assumed metazoan body fossils from Vendian

Sponge paraphyly and the origin of Metazoa

The polymerase chain reaction is used to amplify almost the entire nucleic acid sequence of the 18S rDNA from several hexactinellid, demosponge and calcareous sponge species to suggest that sponges are paraphyletic, the Calcarea being more related to monophyletic Eumetazoa than to the siliceous spongees.