Problematica, trace fossils, and tubes within the Ediacara Member (South Australia): redefining the ediacaran trace fossil record one tube at a time

2011 ◽  
Vol 85 (2) ◽  
pp. 256-265 ◽  
Author(s):  
Aaron Sappenfield ◽  
Mary L. Droser ◽  
James G. Gehling

Ediacaran trace fossils are becoming an increasingly less common component of the total Precambrian fossil record as structures previously interpreted as trace fossils are reinterpreted as body fossils by utilizing qualitative criteria. Two morphotypes, Form E and Form F of Glaessner (1969), interpreted as trace fossils from the Ediacara Member of the Rawnsley Quartzite in South Australia are shown here to be body fossils of a single, previously unidentified tubular constructional morphology formally described herein as Somatohelix sinuosus n. gen. n. sp. S. sinuosus is 2-7 mm wide and 3-14 cm long and is preserved as sinusoidal casts and molds on the base of beds. Well-preserved examples of this fossil preserve distinct body fossil traits such as folding, current alignment, and potential attachment to holdfasts. Nearly 200 specimens of this fossil have been documented from reconstructed bedding surfaces within the Ediacara Member. When viewed in isolated hand sample, many of these specimens resemble ichnofossils. However, the ability to view large quantities of reassembled and successive bedding surfaces within specific outcrops of the Ediacara Member provides a new perspective, revealing that isolated specimens of rectilinear grooves on bed bases are not trace fossils but are poorly preserved specimens of S. sinuosus. Variation in the quality and style of preservation of S. sinuosus on a single surface and the few distinct characteristics preserved within this relatively indistinct fossil also provides the necessary data required to define a taphonomic gradient for this fossil. Armed with this information, structures which have been problematic in the past can now be confidently identified as S. sinuosus based on morphological criteria. This suggests that the original organism that produced this fossil was a widespread and abundant component of the Ediacaran ecosystem.

1984 ◽  
Vol 121 (6) ◽  
pp. 635-643 ◽  
Author(s):  
R. J. F. Jenkins

AbstractThe transitional interval between the Adelaidean and Ediacaran systems in the central Flinders Ranges, South Australia, comprises mainly basinal sediments, with some tuff beds (Bunyeroo Formation) and a widespread thin dolomite bed which apparently evidences a brief regressive episode (base of Wonoka Formation). Body imprints of metazoans, trace fossils and probable faecal pellets are present at various levels in the Ediacaran succession. Comparable assemblages occurring in key successions in southern Africa, northern Russia, Siberia, Newfoundland and England promise a global biostratigraphy. One Ediacaran body fossil occurs in the Yangtze Gorges section, China. Analysis of abundant late Precambrian radiometric data for the present North Atlantic margins suggests that the Ediacaran may be dated between about 590 Ma and ~ 545–540 Ma.


2019 ◽  
Vol 374 (1788) ◽  
pp. 20190221 ◽  
Author(s):  
Michael Archer ◽  
Hayley Bates ◽  
Suzanne J. Hand ◽  
Trevor Evans ◽  
Linda Broome ◽  
...  

The fossil record provides important information about changes in species diversity, distribution, habitat and abundance through time. As we understand more about these changes, it becomes possible to envisage a wider range of options for translocations in a world where sustainability of habitats is under increasing threat. The Critically Endangered alpine/subalpine mountain pygmy-possum, Burramys parvus (Marsupialia, Burramyidae), is threatened by global heating. Using conventional strategies, there would be no viable pathway for stopping this iconic marsupial from becoming extinct. The fossil record, however, has inspired an innovative strategy for saving this species. This lineage has been represented over 25 Myr by a series of species always inhabiting lowland, wet forest palaeocommunities. These fossil deposits have been found in what is now the Tirari Desert, South Australia (24 Ma), savannah woodlands of the Riversleigh World Heritage Area, Queensland (approx. 24–15 Ma) and savannah grasslands of Hamilton, Victoria (approx. 4 Ma). This palaeoecological record has led to the proposal overviewed here to construct a lowland breeding facility with the goal of monitoring the outcome of introducing this possum back into the pre-Quaternary core habitat for the lineage. If this project succeeds, similar approaches could be considered for other climate-change-threatened Australian species such as the southern corroboree frog ( Pseudophryne corroboree ) and the western swamp tortoise ( Pseudemydura umbrina ). This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’


2016 ◽  
Vol 371 (1685) ◽  
pp. 20150287 ◽  
Author(s):  
Graham E. Budd ◽  
Illiam S. C. Jackson

Simulation studies of the early origins of the modern phyla in the fossil record, and the rapid diversification that led to them, show that these are inevitable outcomes of rapid and long-lasting radiations. Recent advances in Cambrian stratigraphy have revealed a more precise picture of the early bilaterian radiation taking place during the earliest Terreneuvian Series, although several ambiguities remain. The early period is dominated by various tubes and a moderately diverse trace fossil record, with the classical ‘Tommotian’ small shelly biota beginning to appear some millions of years after the base of the Cambrian at ca 541 Ma. The body fossil record of the earliest period contains a few representatives of known groups, but most of the record is of uncertain affinity. Early trace fossils can be assigned to ecdysozoans, but deuterostome and even spiralian trace and body fossils are less clearly represented. One way of explaining the relative lack of clear spiralian fossils until about 536 Ma is to assign the various lowest Cambrian tubes to various stem-group lophotrochozoans, with the implication that the groundplan of the lophotrochozoans included a U-shaped gut and a sessile habit. The implication of this view would be that the vagrant lifestyle of annelids, nemerteans and molluscs would be independently derived from such a sessile ancestor, with potentially important implications for the homology of their sensory and nervous systems.


2020 ◽  
Vol 117 (14) ◽  
pp. 7845-7850 ◽  
Author(s):  
Scott D. Evans ◽  
Ian V. Hughes ◽  
James G. Gehling ◽  
Mary L. Droser

Analysis of modern animals and Ediacaran trace fossils predicts that the oldest bilaterians were simple and small. Such organisms would be difficult to recognize in the fossil record, but should have been part of the Ediacara Biota, the earliest preserved macroscopic, complex animal communities. Here, we describeIkaria wariootiagen. et sp. nov. from the Ediacara Member, South Australia, a small, simple organism with anterior/posterior differentiation. We find that the size and morphology ofIkariamatch predictions for the progenitor of the trace fossilHelminthoidichnites—indicative of mobility and sediment displacement. In the Ediacara Member,Helminthoidichnitesoccurs stratigraphically below classic Ediacara body fossils. Together, these suggest thatIkariarepresents one of the oldest total group bilaterians identified from South Australia, with little deviation from the characters predicted for their last common ancestor. Further, these trace fossils persist into the Phanerozoic, providing a critical link between Ediacaran and Cambrian animals.


Author(s):  
Julián Simón López-Villalta

Abstract During the Stage 3 of the Cambrian, several siliciclastic formations were deposited in a shallow platform that would become part of the Iberian Massif, containing abundant trace fossils and the conspicuous ichnospecies Astropolichnus hispanicus, endemic to southwestern Europe during the regional Ovetian stage. The fossil record of these formations has been explored mainly in northern Spain; in southern Spain, the Azorejo Formation (Azorejo Sandstone) is the only unit of this kind, but its paleobiological content has never been described in detail. In this work, the fossil record of the Azorejo Formation is documented from one of its least known outcrops: the Guadiana river section at Picón, Ciudad Real. In this section, the Azorejo Forma- tion contains a diverse trace fossil record for a neritic environment, comprising Agrichnium?, Astropolichnus hispanicus, Belorhaphe, Bergaueria cf. hemispherica, Cochlichnus, Conichnus conicus, Cruziana, Dimorphichnus, Diplichnites, Diplocraterion, Monocraterion, Monomorphichnus bilinearis, Monomorphichnus lineatus, Monomorphichnus lineatus var. giganticus, Palaeophycus, Palaeophycus cf. imbricatus, Planolites, Psammichnites, Rusophycus avalonensis?, Skolithos, Treptichnus pedum, and trace fossils similar to Nereites and Zoophycos. A structure interpreted as the body fossil of a radial organism is also described. Some of these fossils are firstly cited to the Azorejo Formation and the Lower Cambrian of the Iberian Massif. Resumen Durante la Edad 3 del Cámbrico, varias formaciones siliciclásticas fueron depositadas en una plataforma somera que habría de convertirse en parte del Macizo Ibérico, conteniendo abundantes pistas fósiles y la icnoespecie Astropolichnus hispanicus, endémica del sudoeste europeo durante el piso regional Ovetiense. El registro fósil de estas formaciones ha sido explorado principalmente en el norte de España; en el sur, la Formación Azorejo (Areniscas del Azorejo) es la única unidad de este tipo, pero su contenido paleobiológico nunca ha sido descrito en detalle. En este trabajo, el registro fósil de la Formación Azorejo es documentado para uno de sus afloramientos menos conocidos: la sección del río Guadiana en Picón, Ciudad Real. En él la Formación Azorejo contiene variadas pistas fósiles, incluyendo Agrichnium?, Astropolichnus hispanicus, Belorhaphe, Bergaueria cf. hemispherica, Cochlichnus, Conichnus conicus, Cruziana, Dimorphichnus, Diplichnites, Diplocraterion, Monocraterion, Monomorphichnus bilinearis, Monomorphichnus lineatus, Monomorphichnus lineatus var. giganticus, Palaeophycus, Palaeophycus cf. imbricatus, Planolites, Psammichnites, Rusophycus avalonensis?, Skolithos, Treptichnus pedum, una pista similar a Nereites y otra a Zoophycos. Se describe una estructura interpretada como el fósil corporal de un organismo radial. Algunos de estos fósiles se citan por primera vez para las Areniscas del Azorejo y el Cámbrico Inferior del Macizo Ibérico.


2017 ◽  
pp. 1-7 ◽  
Author(s):  
Natalie I. Schroeder ◽  
John R. Paterson ◽  
Glenn A. Brock

Abstract Rare specimens of eldonioids recovered from the lower Cambrian (Series 2, Stage 4) Emu Bay Shale (EBS) Konservat-Lagerstätte represent the first record of the group for the Cambrian of East Gondwana. The disc-shaped body of the EBS taxon bears fine concentric corrugations on the dorsal surface and, ventrally, a series of internal lobes that have primary and secondary bifurcations, as well as a coiled sac. It appears to be most similar to Rotadiscus and Pararotadiscus of the Cambrian Chengjiang and Kaili biotas of South China, respectively. While the structure of the internal lobes would indicate that this occurrence in the EBS represents a new taxon within the Rotadiscidae, lack of detail regarding the precise number of internal lobes and the condition of the circumoral tentacles warrants a more conservative approach in leaving the genus and species under open nomenclature. The EBS specimens also host trace fossils, including the remains of a burrow, which are generally lacking in the body-fossil-bearing layers of the Konservat-Lagerstätte interval. These traces appear to have been made by small organisms and are similar to traces associated with the discs of Pararotadiscus guizhouensis Zhao and Zhu, 1994 from the Kaili Biota. The available taphonomic, paleoenvironmental, and ichnological evidence indicates that the EBS eldonioids are most likely vagrants that were transported or settled into the ‘preservational trap’ and subsequently exposed on the substrate for a brief period before burial, thereby allowing organisms to exploit their carcasses for nutrients or other purposes.


2018 ◽  
Vol 92 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Natalie I. Schroeder ◽  
John R. Paterson ◽  
Glenn A. Brock

AbstractRare specimens of eldonioids recovered from the lower Cambrian (Series 2, Stage 4) Emu Bay Shale (EBS) Konservat-Lagerstätte represent the first record of the group for the Cambrian of East Gondwana. The disc-shaped body of the EBS taxon bears fine concentric corrugations on the dorsal surface and, ventrally, a series of internal lobes that have primary and secondary bifurcations, as well as a coiled sac. It appears to be most similar toRotadiscusandPararotadiscusof the Cambrian Chengjiang and Kaili biotas of South China, respectively. While the structure of the internal lobes would indicate that this occurrence in the EBS represents a new taxon within the Rotadiscidae, lack of detail regarding the precise number of internal lobes and the condition of the circumoral tentacles warrants a more conservative approach in leaving the genus and species under open nomenclature. The EBS specimens also host trace fossils, including the remains of a burrow, which are generally lacking in the body-fossil-bearing layers of the Konservat-Lagerstätte interval. These traces appear to have been made by small organisms and are similar to traces associated with the discs ofPararotadiscus guizhouensis(Zhao and Zhu, 1994) from the Kaili Biota. The available taphonomic, paleoenvironmental, and ichnological evidence indicates that the EBS eldonioids are most likely vagrants that were transported or settled into the ‘preservational trap’ and subsequently exposed on the substrate for a brief period before burial, thereby allowing organisms to exploit their carcasses for nutrients or other purposes.


2021 ◽  
pp. 1-18
Author(s):  
Martin G. Lockley ◽  
Charles W. Helm ◽  
Hayley C. Cawthra ◽  
Jan C. De Vynck ◽  
Michael R. Perrin

Abstract More than 250 Pleistocene vertebrate trace fossil sites have been identified on the Cape south coast of South Africa in aeolianites and cemented foreshore deposits. These discoveries, representing the epifaunal tracks of animals that moved over these sand substrates, complement traditional body fossil studies, and contribute to palaeo-environmental reconstruction. Not described in detail until now, but also important faunal components, are the infaunal traces of animals that moved within these sandy substrates. Six golden mole burrow trace sites (Family Chrysochloridae) have been identified on the Cape south coast. In addition, three sites, including one on the Cape southeast coast, have been identified that show evidence of sand-swimming, probably by a golden mole with a means of locomotion similar to that of the extant Eremitalpa genus. Such traces have not been described in detail in the global ichnology record, and merit the erection of a new ichnogenus Natatorichnus, with two ichnospecies, N. subarenosa ichnosp. nov and N. sulcatus ichnosp. nov. Care is required in the identification of such traces, and the orientation of the trace fossil surface needs to be determined, to avoid confusion with hatchling turtle tracks. Substantial regional Pleistocene dune environments are inferred from these sand-swimming traces.


2000 ◽  
Vol 6 ◽  
pp. 171-182 ◽  
Author(s):  
Ben A. LePage ◽  
Hermann W. Pfefferkorn

When one hears the term “ground cover,” one immediately thinks of “grasses.” This perception is so deep-seated that paleobotanists even have been overheard to proclaim that “there was no ground cover before grasses.” Today grasses are so predominant in many environments that this perception is perpetuated easily. On the other hand, it is difficult to imagine the absence or lack of ground cover prior to the mid-Tertiary. We tested the hypothesis that different forms of ground cover existed in the past against examples from the Recent and the fossil record (Table 1). The Recent data were obtained from a large number of sources including those in the ecological, horticultural, and microbiological literature. Other data were derived from our knowledge of Precambrian life, sedimentology and paleosols, and the plant fossil record, especially in situ floras and fossil “monocultures.” Some of the data are original observations, but many others are from the literature. A detailed account of these results will be presented elsewhere (Pfefferkorn and LePage, in preparation).


PalZ ◽  
2021 ◽  
Author(s):  
Carolin Haug ◽  
Joachim T. Haug

AbstractWhip spiders (Amblypygi), as their name suggests, resemble spiders (Araneae) in some aspects, but differ from them by their heart-shaped (prosomal) dorsal shield, their prominent grasping pedipalps, and their subsequent elongate pair of feeler appendages. The oldest possible occurrences of whip spiders, represented by cuticle fragments, date back to the Devonian (c. 385 mya), but (almost) complete fossils are known from the Carboniferous (c. 300 mya) onwards. The fossils include specimens preserved on slabs or in nodules (Carboniferous, Cretaceous) as well as specimens preserved in amber (Cretaceous, Eocene, Miocene). We review here all fossil whip spider specimens, figure most of them as interpretative drawings or with high-quality photographs including 3D imaging (stereo images) to make the three-dimensional relief of the specimens visible. Furthermore, we amend the list by two new specimens (resulting in 37 in total). The fossil specimens as well as modern whip spiders were measured to analyse possible changes in morphology over time. In general, the shield appears to have become relatively broader and the pedipalps and walking appendages have become more elongate over geological time. The morphological details are discussed in an evolutionary framework and in comparison with results from earlier studies.


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