Ediacaran scavenging as a prelude to predation

2018 ◽  
Vol 2 (2) ◽  
pp. 213-222 ◽  
Author(s):  
James G. Gehling ◽  
Mary L. Droser
Keyword(s):  
Microbial Mats ◽  
South Australia ◽  
Trace Fossil ◽  
Localized Source ◽  
Oxygen Levels ◽  
Stem Group ◽  
Ediacara Biota ◽  
Ecological Innovation ◽  
Large Predators ◽  
Ancient Ecosystems

Predation is one of the most fundamental ecological and evolutionary drivers in modern and ancient ecosystems. Here, we report the discovery of evidence of the oldest scavenging of shallowly buried bodies of iconic soft-bodied members of the Ediacara Biota by cryptic seafloor mat-burrowing animals that produced the furrow and levee trace fossil, Helminthoidichnites isp. These mat-burrowers were probably omnivorous, stem-group bilaterians that largely grazed on microbial mats but when following mats under thin sands, they actively scavenged buried Dickinsonia, Aspidella, Funisia and other elements of the Ediacara Biota. These traces of opportunistic scavengers of dead animals from the Ediacaran of South Australia represent a fundamental ecological innovation and a possible pathway to the evolution of macrophagous predation in the Cambrian. While the Ediacaran oceans may have had oxygen levels too low to support typical large predators, the Helminthoidichnites maker lived in and grazed on microbial mats, which may have provided a localized source of oxygen.

Scratch Traces of Large Ediacara Bilaterian Animals

2014 ◽  
Vol 88 (2) ◽  
pp. 284-298 ◽  
Author(s):  
James G. Gehling ◽  
Bruce N. Runnegar ◽  
Mary L. Droser
Keyword(s):  
Fossil Record ◽  
Microbial Mats ◽  
White Sea ◽  
South Australia ◽  
Trace Fossil ◽  
Cambrian Explosion ◽  
The White Sea ◽  
Feeding Patterns ◽  
Fossil Evidence ◽  
Ediacara Biota

Ediacara fan-shaped sets of paired scratchesKimberichnus teruzziifrom the Ediacara Member of the Rawnsley Quartzite, South Australia, and the White Sea region of Russia, represent the earliest known evidence in the fossil record of feeding traces associated with the responsible bilaterian organism. These feeding patterns exclude arthropod makers and point to the systematic feeding excavation of seafloor microbial mats by large bilaterians of molluscan grade. Since the scratch traces were made into microbial mats, animals could crawl over previous traces without disturbing them. The trace maker is identified asKimberella quadrata, whose death masks co-occur with the mat excavation traces in both Russia and South Australia. The co-occurrence of animals and their systematic feeding traces in the record of the Ediacara biota supports previous trace fossil evidence that bilaterians existed globally before the Cambrian explosion of life in the ocean.

Smothering of microbial mats by macrobiota: implications for the Ediacara biota

2009 ◽  
Vol 166 (6) ◽  
pp. 1117-1121 ◽  
Author(s):  
DUNCAN McILROY ◽  
MARTIN D. BRASIER ◽  
ANDREW S. LANG
Keyword(s):  
Microbial Mats ◽  
Ediacara Biota

scholarly journals Surfing in and on microbial mats: Oxygen-related behavior of a terminal Ediacaran bilaterian animal

Geology ◽  
2019 ◽  
Vol 47 (11) ◽  
pp. 1054-1058 ◽  
Author(s):  
Shuhai Xiao ◽  
Zhe Chen ◽  
Chuanming Zhou ◽  
Xunlai Yuan
Keyword(s):  
Microbial Mats ◽  
Trace Fossil ◽  
Redox Conditions ◽  
Animal Distribution ◽  
Close Relationship ◽  
Bilaterian Animal ◽  
Burrowing Behavior ◽  
Thin Section Analysis ◽  
Section Analysis ◽  
Redox Dynamics

Abstract Geochemical evidence suggests that terminal Ediacaran (ca. 551–539 Ma) oceans experienced expansive anoxia and dynamic redox conditions, which are expected to have impacted animal distribution and behaviors. However, fossil evidence for oxygen-related behaviors of terminal Ediacaran animals is poorly documented. Here, we report a terminal Ediacaran trace fossil that records redox-regulated behaviors. This trace fossil, Yichnus levis new ichnogenus and new ichnospecies, consists of short and uniserially aligned segments of horizontal burrows that are closely associated with microbial mats. Thin-section analysis shows that the trace-making animal moved repeatedly in and out of microbial mats, with mat-burrowing intervals interspersed by epibenthic intermissions. This animal is hypothesized to have been a bilaterian exploring an oxygen oasis in microbial mats. Such intermittent burrowing behavior reflects challenging and dynamic redox conditions in both the water column and microbial mats, highlighting the close relationship between terminal Ediacaran animals and redox dynamics.

scholarly journals BIOLOGICAL AND ECOLOGICAL INSIGHTS FROM THE PRESERVATIONAL VARIABILITY OF FUNISIA DOROTHEA, EDIACARA MEMBER, SOUTH AUSTRALIA

Palaios ◽  
2020 ◽  
Vol 35 (9) ◽  
pp. 359-376
Author(s):  
RACHEL L. SURPRENANT ◽  
JAMES G. GEHLING ◽  
MARY L. DROSER
Keyword(s):  
South Australia ◽  
Ecosystem Dynamics ◽  
Cambrian Explosion ◽  
Ediacara Biota ◽  
National Heritage ◽  
Evolution Of Life ◽  
Fossil Site ◽  
Life On Earth ◽  
Body Fossil

ABSTRACT The Ediacara Biota represents a turning point in the evolution of life on Earth, signifying the transition from single celled organisms to complex, community-forming macrobiota. The exceptional fossil record of the soft-bodied Ediacara Biota provides critical insight into the nature of this transition and into ecosystem dynamics leading up to the so-called “Cambrian Explosion”. However, the preservation of non-biomineralizing organisms in a diversity of lithologies goes hand-in-hand with considerable taphonomic complexity that often shrouds true paleoecological and paleobiological signatures. We address the nature of this taphonomic complexity within the fossiliferous sandstones of the Ediacara Member in South Australia. Utilizing the most fossiliferous outcropping of the Ediacara Member, located at the Nilpena Station National Heritage Ediacara Fossil Site, we conduct a focused, taxon-level biostratinomic characterization of the tubular organism Funisia dorothea. Funisia is the most abundant body fossil in the Ediacara Member, making the characterization of its preservational variability essential to the accurate interpretation of regional paleobiology and paleoecology. We describe remarkable biostratinomic complexity in all Funisia populations at Nilpena, identifying four distinct preservational variants of internal and external molds and four additional successive biostratinomic grades corresponding to loss of external characters. Synthesis of these observations identify the most robust preservational forms of Funisia for use in paleobiological interpretation and highlight the important impact that Funisia's high abundance had on regional paleoecology and on population-scale preservation in the Ediacara Member.

The Shibantan Lagerstätte: insights into the Proterozoic–Phanerozoic transition

2020 ◽  
Vol 178 (1) ◽  
pp. jgs2020-135
Author(s):  
Shuhai Xiao ◽  
Zhe Chen ◽  
Ke Pang ◽  
Chuanming Zhou ◽  
Xunlai Yuan
Keyword(s):  
South China ◽  
Carbonate Rocks ◽  
Microbial Mats ◽  
Ecological Interactions ◽  
Benthic Organisms ◽  
Important Data ◽  
Ediacara Biota ◽  
Marine Carbonate ◽  
Fossil Assemblages ◽  
Marine Carbonate Rocks

The Shibantan Lagerstätte (551–543 Ma) in the Yangtse Gorges area in South China is one of the best-known examples of terminal Ediacaran fossil assemblages preserved in marine carbonate rocks. Taxonomically dominated by benthic organisms, the Shibantan Lagerstätte preserves various photoautotrophs, biomineralizing tubular fossils, Ediacara-type macrofossils (including rangeomorphs, arboreomorphs, erniettomorphs, palaeopascichnids, a possible dickinsoniomorph, the mobile bilaterian Yilingia and soft-bodied tubular fossils), abundant ichnofossils and a number of problematic and dubious fossils. Shibantan fossils provide intriguing insights into ecological interactions among mobile bilaterians, sessile benthic Ediacara-type organisms and microbial mats, thus offering important data to test various hypotheses accounting for the decline of the Ediacara biota and the concurrent expansion of bilaterian bioturbation and mobility across the Proterozoic–Phanerozoic transition.

scholarly journals Paterimitra pyramidalisfrom South Australia: scleritome, shell structure and evolution of a lower Cambrian stem group brachiopod

Palaeontology ◽  
2013 ◽  
Vol 57 (2) ◽  
pp. 417-446 ◽  
Author(s):  
Cecilia M. Larsson ◽  
Christian B. Skovsted ◽  
Glenn A. Brock ◽  
Uwe Balthasar ◽  
Timothy P. Topper ◽  
...  
Keyword(s):  
Shell Structure ◽  
Lower Cambrian ◽  
South Australia ◽  
Stem Group

scholarly journals The scleritome of Paterimitra : an Early Cambrian stem group brachiopod from South Australia

2009 ◽  
Vol 276 (1662) ◽  
pp. 1651-1656 ◽  
Author(s):  
Christian B Skovsted ◽  
Lars E Holmer ◽  
Cecilia M Larsson ◽  
Anette E.S Högström ◽  
Glenn A Brock ◽  
...  
Keyword(s):  
Anterior Margin ◽  
South Australia ◽  
Early Cambrian ◽  
Filter Feeding ◽  
Filter Feeder ◽  
Open Cone ◽  
Life Habit ◽  
Stem Group ◽  
Hard Substrates

Early Cambrian tommotiids are problematic fossil metazoans with external organophosphatic sclerites that have been considered to be basal members of the lophophorate stem group. Tommotiids are almost exclusively known from isolated or rarely fused individual sclerites, which made previous reconstructions of the actual organism highly conjectural. However, the recent discovery of the first articulated specimens of the tommotiid Eccentrotheca revealed a tubular sclerite arrangement (scleritome) that limited the possible life habit to sessile filter feeding and thus further supported a lophophorate affinity. Here, we report the first articulated specimens of a second tommotiid taxon, Paterimitra from the Early Cambrian of the Arrowie Basin, South Australia. Articulated specimens of Paterimitra are composed of two bilaterally symmetrical sclerite types and an unresolved number of small, asymmetrical and irregular crescent-shaped sclerites that attached to the anterior margin of the symmetrical sclerites. Together, the sclerites form an open cone in which the symmetrical sclerites are joined together and form a small posterior opening near the base of the scleritome, while the irregular crescent-shaped sclerites defined a broad anterior opening. The coniform scleritome of Paterimitra is interpreted to have attached to hard substrates via a pedicle that emerged through the small posterior opening (sometimes forming a tube) and was probably a sessile filter feeder. The scleritome of Paterimitra can be derived from the tubular scleritome of Eccentrotheca by modification of basal sclerites and reduction in tube height, and probably represents a more derived member of the brachiopod stem group with the paired symmetrical sclerites possibly homologous to brachiopod valves.

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