Three types of low topography impressions are described from the Late Vendian, which are inter preted as the feeding traces of representatives of the phylum Proarticulata Fedonkin, 1985, which became extinct in the Precambrian. The producers of two types of trace were found. Impressions are usually large and arranged in groups; therefore their correct interpretation only became possible following large scale excava tion work that was carried out for the first time in the Late Vendian deposits of the Arkhangelsk Region in 1996-2001. The single trace (or trace platform) represents a copy of the whole ventral side of the body made by sandstone or only the part of it. Usually trace platforms are arranged in chains and orientated in one dis tinct direction. In spite of some superficial similarity, the fossils are neither body remains nor traces of post mortem compression. The hypothesis of trace formation proposed suggests that the feeding strategy of Proar ticulata was different from any feeding behavior known in large Phanerozoic animals. All types of imprints are identified as belonging to the genus Epibaion Ivantsov, 2002. It is proposed that the Australian fossil Phyl lozoon Jenkins et Gehling, 1978 is also a feeding trace of Proarticulata.

1 morgana@ufba.br; 2 paleoicno@yahoo.com.br RESUMO As ocorrências de fósseis de organismos de corpo mole em rochas proterozóicas brasileiras são ainda incipientes. Na Formação Camarinha há registros de estruturas interpretadas até então como traços de repouso de organismos medusóides, procedentes do Município de Campo Largo, Estado do Paraná. O presente estudo tem como objetivo reinterpretar estes fósseis, que correspondem a estruturas discóides, elipsóides e com orientação preferencial; podem ocorrer marcas radiais e depressões centrais. Os fósseis estudados foram atribuídos ao gênero Beltanelliformis, corpos fossilizados de organismos de afinidade incerta, restritos ao período Ediacarano e relacionados à Biota de Ediacara, o que permite deduzir que ao menos o topo da Formação Camarinha, teria sido depositado neste intervalo temporal. Os fósseis apresentam preservação do tipo Nama, que corresponde a moldes simples em 3 dimensões. Palavras-chave: Beltanelliformis, Formação Camarinha, Ediacarano.

Lower and Middle Cambrian carbonate rocks of the Çal Tepe Formation, cropping out in the western Taurus Mountains, yielded a large number of microfossil remains. Small shelly fossils from a single level in the upper Lower Cambrian represent a high diversity biota that could be related to the «Cambrian explosion». Microfossil association from the lower Middle Cambrian sediments of the Çal Tepe Formation is taxonomically very reduced and a dominant taxon is Hadimopanella GEDIK. This sudden change could be attributed to a deepening of the basin during the early Middle Cambrian transgression.

Convincingly specific homologies between Ediacarans and members of recognized animal phyla have remained elusive, thus casting a shadow of doubt over the animal affinity interpretation of Ediacaran phylogeny. Spriggina floundersi, for example, has been described as a tomopterid annelid, an arthropod, and a frondose vendobiont. Reanalysis of Spriggina demonstrates the presence of genal spines (comparable to those of fallotaspidoid and paradoxidid trilobites), a cephalic region homologous to the effaced cephalons of agraulid and skehanid trilobites, and a dual cephalic region (also seen in Parvancorina) that compares to the parts of a trilobite cephalon anterior and posterior of the facial suture. Spriggina is thus a trilobitoid ecdysozoan, a conclusion in accord with Sven Jorgen Birket-Smith's inference of an arthropod affinity for Spriggina. This result is among the first confident phylogenetic linkages between an Ediacaran and a Cambrian animal, and thus helps to demonstrate that Paleozoic animals could indeed be descended from Ediacarans. If Spriggina is a direct ancestor of trilobites, then a case can be made that Spriggina itself (or a direct descendant) served as the predator taxon that initiated the Cambrian ecotone transformation (McMenamin, M. A. S., 2003, Origin and early evolution of predators: The ecotone model and early evidence for macropredation. In: P. Kelley, M. Kowalewski and T. Hansen, eds., Predator-Prey Interactions in the Fossil Record). Such heterotrophy, however, does not preclude the possibility of photosymbiosis or other types of mixotrophy in Ediacarans with high surface area such as Marywadea and Dickinsonia.

Neoproterozoic BIFs occur in Tonian, Cryogenian, and Ediacaran successions, and are not restricted
to the middle Cryogenian (c. 715 Ma) glaciation. Many Neoproterozoic BIFs (North and South
America, southern Africa, and Australia) were deposited in glacially influenced settings, and are
traditionally assigned to the Rapitan type. Other occurrences in South America, Africa, and Asia,
however, bear no indications of glacial processes and can be assigned to the Algoma and Lake Superior
types.
Chemostratigraphy is a powerful tool for unraveling the depositional setting of Neoproterozoic
BIFs. Some of the most useful methods are REE distribution, especially the Eu and Ce normalized
concentrations, iron speciation, Nd and Cr isotopes (δ53Cr). Whereas Rapitan type BIFs exhibit no Eu
or Ce anomalies, Algoma type Neoproterozoic BIF show both. Positive δ53Cr values characterize glacially
influenced BIFs, and differentiates them from nonfractionated, mantle-like δ53Cr values of
Algoma type BIFs. The latter are also characterized by high Cr concentrations. The most positive δ53Cr
values occur in the open-shelf, Lake Superior type BIFs, especially those of Ediacaran age. Given the
consistent secular variations exhibited by δ53Cr, it is envisaged that it may be used for correlation and
geochronology once the available database grows sufficiently.
It is demonstrated clearly that glaciation was not the main mechanism responsible for deposition of
BIFs in the Neoproterozoic. Hydrothermal activity related to the rifting of Rodinia probably played the
key role in their reappearance after the Mesoproterozoic gap, and promoted a return to ferruginous
conditions after the demise of Mesoproterozoic euxinic oceans.

This book aims to address the deficiencies of contemporary evolution studies by evaluating Multi-Torus or Morphogenetic Torus Theory using the fossil record. The book begins with description of and discussion of one of most recently recognized members of the Ediacaran biota, a fossil that looks astonishingly like a fossilized morphogenetic torus. This is followed by evaluation a newly discovered giant trilobite with characteristics that appear to support toroidal morphogenesis theory. The book then looks at an application of the model to scleritome theory (i.e., the theory of shell evolution) and to the Cambrian origin of mollusks and brachiopods, and as a result will develop a new and powerful dual application of torus scleritome theory. Next follows focus on the early development of cephalopods and a new variant of the torus called hypertorus. Finally, the book considers a counterexample to toroidal morphogenesis in the growth of marine microbes known as foraminifera. Using a newly discovered foraminiferal microbiota (that turns out to be exactly contemporary with the new giant trilobite), the book explores the metacellular/chambering style of morphogenesis that stands in direct contrast to toroidal morphogenesis as a parallel morphogenetic system.

Three new genera of transversely articulated Metazoa are described from the Upper Vendian of the Arkhangelsk Region (Russia). Tamga gen. nov. and Lossinia gen. nov. are recognized to be closely related to the extinct Precambrian phylum Proarticulata; Ivovicia gen. nov. is considered as a true member of Proarticulata; all of the new genera are monotypic. Onega stepanovi Fedonkin is also reinterpreted as Proarticulata. The replacement generic name Archaeaspinus is introduced for the preoccupied Archaeaspis Ivantsov. Vendomia menneri Keller is assigned to Dickinsonia Sprigg.

The evolutionary emergence of animals is one of the most significant episodes in the history of life, but its timing remains poorly constrained. Molecular clocks estimate that animals originated and began diversifying over 100 million years before the first definitive metazoan fossil evidence in the Cambrian. However, closer inspection reveals that clock estimates and the fossil record are less divergent than is often claimed. Modern clock analyses do not predict the presence of the crown-representatives of most animal phyla in the Neoproterozoic. Furthermore, despite challenges provided by incomplete preservation, a paucity of phylo-genetically informative characters, and uncertain expectations of the anatomy of early animals, a number of Neoproterozoic fossils can reasonably be interpreted as metazoans. A considerable discrepancy remains, but much of this can be explained by the limited preservation potential of early metazoans and the difficulties associated with their identification in the fossil record. Critical assessment of both records may permit better resolution of the tempo and mode of early animal evolution.

The Cambrian Explosion is arguably the most extreme example of a biological radiation preserved in the fossil record, and studies of Cambrian Lagerstätten have facilitated the exploration of many facets of this key evolutionary event. As predation was a major ecological driver behind the Explosion-particularly the radiation of biomineralising metazoans-the evidence for shell crushing (durophagy), drilling and puncturing predation in the Cambrian (and possibly the Ediacaran) is considered. Examples of durophagous predation on biomineralised taxa other than trilobites are apparently rare, reflecting predator preference, taphonomic and sampling biases, or simply lack of documentation. The oldest known example of durophagy is shell damage on the problematic taxon Mobergella holsti from the early Cambrian (possibly Terreneuvian) of Sweden. Using functional morphology to identify (or perhaps misidentify) durophagous predators is discussed, with emphasis on the toolkit used by Cambrian arthropods, specifically the radiodontan oral cone and the frontal and gnathobasic appendages of various taxa. Records of drill holes and possible puncture holes in Cambrian shells are mostly on brachiopods, but the lack of prey diversity may represent either a true biological signal or a result of various biases. The oldest drilled Cambrian shells occur in a variety of Terreneuvian-aged taxa, but specimens of the ubiquitous Ediacaran shelly fossil Cloudina also show putative drilling traces. Knowledge on Cambrian shell drillers is sorely lacking and there is little evidence or consensus concerning the taxonomic groups that made the holes, which often leads to the suggestion of an unknown 'soft bodied driller'. Useful methodologies for deciphering the identities and capabilities of shell drillers are outlined. Evidence for puncture holes in Cambrian shelly taxa is rare. Such holes are more jagged than drill holes and possibly made by a Cambrian 'puncher'. The Cambrian arthropod Yohoia may have used its frontal appendages in a jack-knifing manner, similar to Recent stomatopod crustaceans, to strike and puncture shells rapidly. Finally, Cambrian durophagous and shell-drilling predation is considered in the context of escalation-an evolutionary process that, amongst other scenarios, involves predators (and other 'enemies') as the predominant agents of natural selection. The rapid increase in diversity and abundance of biomineralised shells during the early Cambrian is often attributed to escalation: enemies placed selective pressure on prey, forcing phenotypic responses in prey and, by extension, in predator groups over time. Unfortunately, few case studies illustrate long-term patterns in shelly fossil morphologies that may reflect the influence of predation throughout the Cambrian. More studies on phenotypic change in hard-shelled lineages are needed to convincingly illustrate escalation and the responses of prey during the Cambrian.

Figure 2.1: Generalized regional stratigraphy, modified from Prave et al.(1991), with composite measured section indicating principal fossiliferous horizons. Locality 1: Spring Mountains. 2: southern Nopah Range. 3: Funeral Mountains.(sh= shale; vf–f–c= very fine–fine–coarse sandstone; cg= coarse–pebbly sandstone and conglomerate; sd= sandy dolostone; d= dolostone)

Life is an inordinately complex unsolved puzzle. Despite significant theoretical progress, experimental anomalies, paradoxes, and enigmas have revealed paradigmatic limitations. Thus, the advancement of scientific understanding requires new models that resolve fundamental problems. Here, I present a theoretical framework that economically fits evidence accumulated from examinations of life. This theory is based upon a straightforward and non-mathematical core model and proposes unique yet empirically consistent explanations for major phenomena including, but not limited to, quantum gravity, phase transitions of water, why living systems are predominantly CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur), homochirality of sugars and amino acids, homeoviscous adaptation, triplet code, and DNA mutations. The theoretical framework unifies the macrocosmic and microcosmic realms, validates predicted laws of nature, and solves the puzzle of the origin and evolution of cellular life in the universe. Life 2012, 2 2

There are only two kinds of organisms on the Earth: prokaryotes and eukaryotes. Although eukaryotes are considered to have evolved from prokaryotes, there were no previously known intermediate forms between them. The differences in their cellular structures are so vast that the problem of how eukaryotes could have evolved from prokaryotes is one of the greatest enigmas in biology. Here, we report a unique organism with cellular structures appearing to have intermediate features between prokaryotes and eukaryotes, which was discovered in the deep sea off the coast of Japan using electron microscopy and structome analysis. The organism was 10 µm long and 3 µm in diameter, having >100 times the volume of Escherichia coli. It had a large 'nucleoid', consisting of naked DNA fibers, with a single nucleoid membrane and endosymbionts that resemble bacteria, but no mitochondria. Because this organism appears to be a life form distinct from both prokaryotes and eukaryotes but similar to eukaryotes, we named this unique microorganism the 'Myojin parakaryote' with the scientific name of Parakaryon myojinensis ('next to (eu)karyote from Myojin') after the discovery location and its intermediate morphology. The existence of this organism is an indication of a potential evolutionary path between prokaryotes and eukaryotes.

Ongoing discoveries of new rangeomorph fossils from the Ediacaran of Avalonia allow us to put forward a unified and approachable scheme for the description and phylogenetic analysis of frondose genera and their species. This scheme focuses upon the branching morphology of rangeomorph units. Our system has the advantage of being applicable at all visible scales of subdivision and is suitable for the study of isolated fragmentary specimens. The system is also free from hypothesis about biological affinity and avoids tectonically influenced features such as shape metrics. Using a set of twelve character states within this unified scheme, we here present emended diagnoses for Beothukis, Avalofractus, Bradgatia, Hapsidophyllas, Fractofusus, Trepassia and Charnia, together with a more extensive taxonomic treatment of the latter genus. For those forms that fall within the morphological spectrum between Trepassia and Beothukis, we introduce Vinlandia gen. nov. It is hoped that this scheme will provide a robust framework for future studies of rangeomorph ontogeny and evolution.

The term ‘Ediacara Biota’ (or many variants thereof) is commonly used to refer to certain megascopic fossils of Precambrian and early Palaeozoic age – but what does the term actually mean? What differentiates a non-Ediacaran ‘Ediacaran’ and an Ediacaran ‘Ediacaran’ from an Ediacaran non-‘Ediacaran’? Historically, the term has been used in either a geographic, stratigraphic, taphonomic, or biologic sense. More recent research and new discoveries, however, mean that the term cannot actually be defined on any of these bases, or any combination thereof. Indeed, the term is now used and understood in a manner which is internally inconsistent, and unintentionally implies that these fossils are somehow distinct from other fossil assemblages, which is simply not the case. Continued use of the term is a historical relic, which has led in part to incorrect assumptions that the ‘Ediacara Biota’ can be treated as a single coherent group, has obscured our understanding of the biological change over the Precambrian–Cambrian boundary, and has confused research on the early evolution of the Metazoa. In the future, the term ‘Ediacaran’ should be restricted to purely stratigraphic usage, regardless of affinity, geography, or taphonomy; sufficient terminology also exists where reference to specimens on a geographic, taphonomic, or biologic basis is required. It is therefore time to abandon the term ‘Ediacara Biota’ and to instead treat equally all of the fossils of the Ediacaran System.

Distinguishing Ediacaran trace fossils from tubular body fossils can be a challenge, and several Ediacaran fossils previously interpreted as animal traces have been shown to be tubular body fossils. Nonetheless, true Ediacaran trace fossils are present, but they are relatively few and morphologically simple, dominated
by horizontal trails and shallow burrows. Such simple morphologies have been taken as evidence for a modest behavioral complexity and limited geobiological impact of animal bioturbators before the Cambrian explosion. Here we report three types of trace fossils—horizontal tunnels, surface tracks/trails,
and vertical traces—from the latest Ediacaran Dengying Formation (551–541 Ma) in the Yangtze Gorges area of South China. Cross-cutting tunnels and the presence of scratch marks indicate that these traces are unlikely tubular body fossils; instead, these three types of traces likely represent animal activities related to under-mat feeding, epibenthic locomotion, and temporary dwelling, respectively. We show that these three types of traces were constructed by the same bilaterian animals that had moderately complex interactions with microbial mats to exploit nutrients and O2 resources. These animals heralded
a new age in ecosystem engineering, animal–sediment interaction, and biogeochemical cycling.

In September of 1869, while studying sponges off the Norwegian island of Gisoe, Ernst Haeckel (1834-1919) discovered a tiny, flagellated ball-shaped organism swimming about in his samples. Appearing first to be the planula larva of an invertebrate marine animal further observation revealed it to be a colony of flagellated cells with a complex life cycle transitioning between multicellular and single-cell stages and several distinct forms of protozoa. Haeckel named it Magosphaera planula (the "magician's ball") and it eventually assumed a central role in his theories of animal evolution, appearing as the modern exemplar of the blastaea stage in his gastraea theory of metazoan evolution. Throughout the latter half of the nineteenth century and into the twentieth it was an object of considerable scientific interest, and yet it was only ever observed by Haeckel himself and then only the once. Eventually it faded altogether from scientific discussion. This paper traces the rise and fall of Magosphaera as an important epistemic object in the theories of Haeckel and other biologists, and an attempt is made to identify what exactly the organism (or organisms!) was that Haeckel observed in the fall of 1869.

La biota ediacárica representa uno de los mayores hitos en la historia evolutiva del planeta, pues contiene algunas de las primeras formas de vida animal pluricelular macroscópica bien conocida en el registro fósil y que presenta gran diversidad morfológica e interacciones ecológicas complejas, además de poseer integrantes microscópicos de gran relevancia evolutiva como los posibles primeros animales triploblásticos. Su posición estratigráfica corresponde con el final del Neoproterozoico, tiempo de aparición en el registro fósil de algunos de los primeros animales eumetazoos. La mayoría de los planes corporales de los organismos macroscópicos del Ediacárico no tienen equivalentes modernos e incluyen simetrías triradiales, octoradiales y fractales. La biota ediacárica vio su final al evolucionar los primeros organismos macrodepredadores con exoesqueletos que luego dominarían los ecosistemas del Fanerozoico.

A new macrofossil genus and species from the Late Vendian of the Urals is described. Fossils are
found on a bedding plane between the sandstone and mudstone and are represented mainly by casts on the
sandstone surface. The casts are negative and flatbottomed, covered with numerous, closely spaced uniform
indentations and rimmed by a small, low, narrow, flat flange. This fossil can be reconstructed as a disk con
sisting of two layers. The top layer was less resistant and probably unstructured. The bottom layer was denser
and was structured (either with a tuberculate surface or consisted of loosely packed spherical elements).
Kuckaraukia multituberculata gen. et sp. nov. could be interpreted as a unitary organism or as a colony of
motionless benthic organisms.

New localities with Precambrian fossils have been found in Charnwood Forest. New specimens include Hadrynichorde aff. catalinensis, which is a species potentially new to Britain. Also revealed are juvenile forms of organisms not recorded previously, and fossil forms that have no clear associations with currently recognised species.

The late Ediacaran soft-bodied macroorganism Dickinsonia (age range approx. 560–550 Ma) has often been interpreted as an early animal, and is increasingly invoked in debate on the evolutionary assembly of eumetazoan body plans. However, conclusive positive evidence in support of such a phylogenetic affinity has not been forthcoming. Here we subject a collection of Dickinsonia specimens interpreted to represent multiple ontogenetic stages to a novel, quantitative method for studying growth and development in organisms with an iterative body plan. Our study demonstrates that Dickinsonia grew via pre-terminal 'deltoidal' insertion and inflation of constructional units, followed by a later inflation-dominated phase of growth. This growth model is contrary to the widely held assumption that Dickinsonia grew via terminal addition of units at the end of the organism bearing the smallest units. When considered alongside morphological and behavioural attributes, our developmental data phylogenetically constrain Dickinsonia to the Metazoa, specifically the Eumetazoa plus Placo-zoa total group. Our findings have implications for the use of Dickinsonia in developmental debates surrounding the metazoan acquisition of axis specification and metamerism.

The morphology and stratigraphic distribution of Harlaniella podolica Sokolov, 1972 and H. ingriana Ivantsov, sp. nov. were investigated using the collection of impressions sampled recently in Upper Vendian sections of Russia (southeastern White Sea region) and Ukraine (Podoliya). These fossils, which were previ ously considered as representing coprolites or grazing or locomotion traces, are interpreted as internal casts and impressions of fragments of tubes of initially organic composition. Streptichnus narbonnei Jensen et Run negar, 2005 from Vendian-Cambrian boundary strata of Namibia are also attributed to this group. It is assumed that the tubes are similar to remains of the algal genera Vendotaenia Gnilovskaya, 1971 from Vendian deposits of the East European Platform and Liulingjitaenia Chen et Xiao, 1992 from Sinian sections of China.

The near-simultaneous appearance of most modern animal
body plans (phyla) ~530 million years ago during the
Cambrian explosion is strong evidence for a brief interval
of rapid phenotypic and genetic innovation, yet the exact
speed and nature of this grand adaptive radiation remain
debated [1–12]. Crucially, rates of morphological evolution
in the past (i.e., in ancestral lineages) can be inferred from
phenotypic differences among living organisms—just as
molecular evolutionary rates in ancestral lineages can be
inferred from genetic divergences [13]. We here employed
Bayesian [14] and maximum likelihood [15] phylogenetic
clock methods on an extensive anatomical [16] and genomic
[17] data set for arthropods, the most diverse phylum in the
Cambrian and today. Assuming an Ediacaran origin for
arthropods, phenotypic evolution was ~4 times faster, and
molecular evolution ~5.5 times faster, during the Cambrian
explosion compared to all subsequent parts of the Phanerozoic.
These rapid evolutionary rates are robust to assumptions
about the precise age of arthropods. Surprisingly,
these fast early rates do not change substantially even if
the radiation of arthropods is compressed entirely into the
Cambrian (~542 mega-annum [Ma]) or telescoped into the
Cryogenian (~650 Ma). The fastest inferred rates are still
consistent with evolution by natural selection and with
data from living organisms, potentially resolving ‘‘Darwin’s
dilemma.’’ However, evolution during the Cambrian explosion
was unusual (compared to the subsequent Phanerozoic)
in that fast rates were present across many lineages.

Sole markings from the Upper Cambrian Booley Bay Formation at Booley Bay, Co. Wexford, Ireland, previously described as the Ediacaran-type fossil Ediacaria booleyi appear to possess a number of morphological characteristics which are not consistent with assignment to the genus Ediacaria, nor any other known Ediacaran taxon. An inorganic origin for the structures has been proposed by several workers; we tentatively consider them to be at least in part organic, and are currently working to evaluate this hypothesis critically. If organic, the organisms must have had a density similar to that of the sediment in which they were emplaced, and to survive the transport process, they must have had a rigid integument. Neither of these properties appears to be consistent with an interpretation as an Ediacaran-type organism. We suggest here that the Booley Bay specimens should be removed from the genus Ediacaria. If Ediacaria booleyi is not related to known Ediacaran organisms, this would remove a key aspect of the argument against a mass extinction at the Precambrian/Cambrian boundary.

ABSTRACT In the Death Valley region of the Mojave Desert, the Neoproterozoic-Cambrian boundary lies in the lower member of the Wood Canyon Formation (lmWCF). Below the boundary, the lower few meters of the lmWCF contain an assemblage of Ediacaran fossils, including the saclike genus Ernietta, the frondlike Swartpuntia, and the tubular fossils Archaeichnium, Cloudina, Corumbella, and Onuphionella. Associated trace fossils include bed-parallel burrows such as Planolites and Helminthoidichnites.

"A new ichnogenus and ichnospecies, Lamonte trevallis, is formally described from the Shibantan Member limestone
of the upper Ediacaran Dengying Formation, Yangtze Gorges area, South China. It is characterized by horizontal
tunnels connected with short vertical burrows and surface trails. The horizontal burrows are elliptical or
bilobed in transverse cross-section, preserved in full relief, and filled with carbonate intraclasts, micrites, as well
as calcite and silica cements. They occur exclusively in silty, crinkled, and microlaminated layers that are
interpreted asamalgamated cyanobacterial microbial mats; no burrows have been found in intraclastic layers adjacent
to the microlaminated layers. The vertical traces are filledwith the same material as the burrows, but they
typically project through the crinkled microlaminae and are exposed on the bedding surface. The surface tracks
are always preserved in negative epirelief or positive hyporelief and consist of two parallel series of either sharp
scratch marks or small knobs. The burrow infill has δ18Ocarb and δ13Ccarb values distinct from, but intermediate
between, microlaminated and intraclastic layers, consistentwith petrographic observation that burrowinfill consists
of a mixture of early carbonate cements, intraclasts, and micrites. Bedding plane bioturbation intensity
(20–40%)—measured as percentage of bedding plane area covered by L. trevallis traces—is comparable to similar
measurements in pre-trilobite Cambrian carbonates. The exclusive occurrence of L. trevallis within microbial
mats may have both taphonomic and ecological significance. These mats may have provided firm substrates
and localized geochemical conditions that contributed to the structural integrity of the burrows, and they may
have also facilitated early diagenetic cementation of burrow infill, thus facilitating burrow preservation. The
close association of these burrows with microbial mats implies that the trace producers actively mined
cyanobacterial mats to exploit oxygen or nutrient resources. The trace makers of L. trevallis were better able to
utilize the resources around them than many other Ediacaran trace makers and provide an ichnological record
of a flourishing benthic ecology in late Ediacaran oceans at the dawn of the agronomic revolution."

Discoidal fossils, despite being the oldest, youngest, and most common elements of the Ediacaran biota, have not received their fair share of attention. Taxonomy of discoidal fossils is currently dubious, and some forms have not been properly re-examined since the initial incorrect descriptions as medusae.