The DOI matches its Crossref record; 54 of the 56 references it cites were found in a registry or an index; none of the 70 sources its claims cite is checked for support yet.
Tubular compression fossils from the Ediacaran Nama group, Namibia
Open accessAbstract
Abundant tubular macrofossils occur in finely laminated siltstones and shales of the 548–542 Ma Schwarzrand Subgroup, Nama Group, Namibia. The Nama tubes occur in both the Vingerbreek and Feldschuhhorn members commonly in dense populations and always in fine-grained, lower shore-face lithologies deposited below fair-weather wave base. The tubes are preserved mostly as compressed casts and molds that range in width from 0.6 to 2.1 mm; apparently incomplete specimens reach lengths up to 10 cm. All specimens show sinuous bending and occasional brittle fracture, indicating an original construction of strong but flexible organic matter. Feldschuhhorn specimens preserve fine longitudinal pleats or folds that record pliant organic walls, but the older Vingerbreek populations do not. Similarly, some specimens in the Feldschuhhorn Member display branching, while Vingerbreek tubes do not. The abundant Feldschuhhorn tubes are assigned to the widespread Ediacaran problematicum Vendotaenia antiqua; however, the distinctive Vingerbreek population remains in open nomenclature. The most abundant fossils in Nama rocks, these tubes resemble populations in Ediacaran successions from Russia, China, Spain, and elsewhere. Beyond their local importance, then, such tubes may turn out to be the most abundant record of Ediacaran life.
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Written from the paper’s full text.
TL;DR
Abundant tubular compression fossils occur in the 548–542 Ma Schwarzrand Subgroup, Nama Group, Namibia, preserved as casts and molds in fine-grained lower shore-face deposits. The Feldschuhhorn population is assigned to *Vendotaenia antiqua*, while the older Vingerbreek population remains in open nomenclature; such tubes may be among the most abundant Ediacaran macrofossils.
Key findings
- Tubes range from 0.6 to 2.1 mm in width; incomplete specimens reach lengths up to 10 cm, and both Vingerbreek and Feldschuhhorn populations show a bimodal width distribution. Sinuous bending and occasional brittle fracture indicate strong but flexible organic matter.
- Feldschuhhorn specimens preserve fine longitudinal pleats or folds and rare branching (pseudomonopodial and dichotomous); Vingerbreek tubes lack folds and branching. The Feldschuhhorn tubes are assigned to *Vendotaenia antiqua*, while the Vingerbreek population is left in open nomenclature.
- Feldschuhhorn internal molds consist primarily of iron-rich phyllosilicates, including chlorite; SEM shows a honeycombed wall pattern consistent with pyrite crystals later weathered out. Vingerbreek tubes and matrix differ in composition, and some Vingerbreek specimens are preserved as raised ridges, a style unique to that member.
- The Nama tubes resemble Ediacaran populations from Russia, China, Spain, and elsewhere; the paper suggests they may be the most abundant record of Ediacaran life and a significant component of Ediacaran biomass.
Methods
- Fossils were collected from the Vingerbreek Member at Kliphoek farm and the Feldschuhhorn Member at Sonntagsbrunn farm, southern Witputs sub-basin; fossils occur through approximately 50 m and 70 m of section, respectively, in fine-grained, parallel-laminated rocks.
- Morphology was analyzed using light microscopy and SEM with EDAX; length and width of individual tubes were measured on approximately 75% of collected hand samples to generate size distributions. Specimens were deposited under accession numbers F608–F620.
- Geochronologic context comes from U/Pb zircon dates: 548.8 ±1 Ma (Hoogland Member), 545.1 ±1 Ma, and 543 ±1 Ma (Spitskop Member), which bracket the fossils.
Limitations
- The paper states that morphological simplicity and a general lack of distinguishing features make definitive taxonomic categorization difficult; the Vingerbreek population is left in open nomenclature. No definitively complete fossils were found, so original lengths were presumably longer, and terminal swellings were not confidently interpreted because they could be taphonomic artifacts.
- The paper states that Vingerbreek material can be difficult to distinguish from simple trace fossils, and some raised-ridge specimens might be interpreted as trace fossils if found in isolation. It also notes that a *Thioploca*-like interpretation breaks down on size and lack of branching, and that absent reproductive structures make it challenging to differentiate cylindrical fossils of macroscopic green, red, or brown algae.
- Evident from the text: the study is based on two localities/members in the southern Nama sub-basin, and most tube walls have low or no preserved organic content (hydrofluoric acid maceration of Vingerbreek samples failed to reveal preserved organic matter), limiting direct biological characterization.
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Claims the paper makes
46 Not checked yet · 44 Own interpretation · 37 No basis given · 33 Own result
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Abundant tubular macrofossils occur in finely laminated siltstones and shales of the 548-542 Ma Schwarzrand Subgroup, Nama Group, Namibia.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Many of the fossils in the Vingerbreek Member occur in beds interpreted as the interval of maximum flooding of the shelf.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > GEOLOGIC SETTING
plaincorrelational- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“always in fine-grained, lower shore-face lithologies deposited below fairweather wave base”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“these tubes resemble populations in Ediacaran successions from Russia, China, Spain, and elsewhere”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plaincorrelational- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Tubes typically have sharp terminations”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“SEM analysis of Feldschuhhorn specimens (Figure 6.4) shows a distinctive honeycombed pattern in the walls of the fossils not found in the surrounding matrix”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“while Vingerbreek tubes do not”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“the lack of evidence for cross-cutting relationships or bioturbation in these strata provides still further evidence in support of a body fossil interpretation”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“apparently incomplete specimens reach lengths up to 10 cm”
- Also stated in: § Preserved Morphology. · plain
“Tubes reach lengths of up to 10 cm”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plain- Asserted: passes — The authors put it forward as true.
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- Also stated in: § Preserved Morphology. · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“some specimens in the Feldschuhhorn Member display branching”
- Also stated in: § Preserved Morphology. · boosted
“Unambiguous branching, both pseudomonopodial and dichotomous, occurs in Feldschuhhorn material”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
boosted- Asserted: passes — The authors put it forward as true.
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- Also stated in: § Preserved Morphology. · boosted
- It may state two separate claims as one. 61
- Probably not a substantial claim. 26
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Many specimens show sharp terminations formed by breakage, a feature that would not be found in a trace fossil.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
hedged- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“As with the Vingerbreek Member, the Feldshuhhorn shales occupy a position of maximum flooding on the shelf.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > GEOLOGIC SETTING
plain- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Fossils occur in both the lower and upper parts of the Schwarzrand Subgroup, in the Vingerbreek Member of the Nudaus Formation, and in the Feldschuhhorn Member of the overlying Urisis Formation.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > GEOLOGIC SETTING
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
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In the paper
“The surrounding matrix of Feldschuhhorn specimens is similarly clay-rich; infill material differs from matrix predominantly in its elevated C and Fe abundances”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“the tubes tend to be of near-constant diameter on any single bedding plane -tube width varies between bedding planes, but rarely within them.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
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In the paper
“A few of the Feldschuhhorn specimens show terminal swellings”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plain- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In hand specimens, the majority of the fossils stand out clearly because of their strong color contrast to the surrounding matrix; individuals are generally either rust-red or black.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
boosteddirect- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Vingerbreek and Feldschuhhorn populations both show a bimodal width distribution”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
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In the paper
“All specimens show sinuous bending and occasional brittle fracture”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The Nama tubes occur in both the Vingerbreek and Feldschuhhorn members commonly in dense populations”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Specimens in previously examined Vingerbreek material include individuals with faint transverse annulations (Bradley, 1998), but their occurrence is neither as pronounced nor as widespread within the population as the annulations in Sabellidites.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Bradley, 1998
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Type populations of T. podolica differ from Vingerbreek populations most conspicuously in their smaller size (Table 1) and propensity to twist and bend sharply.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plaincorrelational- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“The Vingerbreek tubes differ from Sabellidites in that some populations of the latter form interwoven filaments (Ivantsov, 1990;Moczydlowska, 2003), of which no evidence is found in Nama fossils.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Ivantsov, 1990
- Not checked yetcites Moczydlowska, 2003
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“In the Nama Group, tubular macrofossils, conventional Ediacaran remains, and calcified macrofossils are interstratified, segregating along paleoenvironmental lines.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plaincorrelational- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“A handful of samples from the Vingerbreek are preserved as raised ridges, as opposed to compressions, a preservation style unique to this member (Figure 4.3, 8.3).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“However, most such organisms show variation in width along their lengths and display external morphological features not found in any of the Nama compression fossils.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Additional information
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“No evidence of evacuated pyrite crystals were observed under SEM, consistent with the tubes' darker and presumably unoxidized coloration.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plaincorrelational- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The Feldschuhhorn populations record occasionally branching tubes prone to decomposition by sulfate reducing bacteria, axial twisting during burial, and folding upon compression.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“fossils occur through 70 m of section, always in fine-grained, parallel-laminated rocks interbedded with fine-grained sandstones deposited during storms.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plaincorrelationalSingle case- Asserted: passes — The authors put it forward as true.
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In the paper
“The organic content of most tube walls is low or non-existent; hydrofluoric acid maceration of Vingerbreek samples failed to reveal preserved organic matter.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In short, Vingerbreek and Feldschuhhorn siltstones and shales both contain abundant macrofossils of originally tubular organisms, but they preserve different populations.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“The older Vingerbreek fossils do not branch, do not twist during deposition or fold during compression, and do not appear to have been equally accessible to sulfate-reducers (which could reflect environment as much as wall chemistry).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
hedged- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In both localities, tubular macrofossils are abundant, occurring in high concentrations of randomly oriented individuals that cover bedding surfaces.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Similar macrofossils in other localities are commonly preserved as carbonaceous compressions, but that is not the case for most of the specimens considered here.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In contrast, Vingerbreek material lacks obvious folds and does not show elevated levels of carbon.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Relative to matrix, tube infillings are enriched in Fe and, notably, Mg, but depleted in K, Al, and Si.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Additionally, the lack of annulations in dozens of specimens examined from each locality and the faint and superficial quality of those observed emphasizes the possibility that those seen in isolated specimens could be preservational artifacts.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Additional information
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Sandstone bedding surfaces rarely contain simple trace fossils; otherwise the tubes are the only macrofossils evident in outcrop.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Vendian Vendotaenia are preserved as carbonaceous films, especially in drill core samples, yet they provide close counterparts in terms of 12 morphology and size to the Feldschuhhorn specimens.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plaincorrelational- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
In the paper
“Vidal (1989), however, viewed these features as artifacts, reinterpreting V. antiqua as the preserved sheaths of sulfur-oxidizing bacteria such as Thioploca.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Vidal, 1989
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“Vendotaenia populations have not only been reported from numerous localities within Redkino and Kotlin (<555 and >543 Ma: Martin et al., 2000) strata of the Eastern European Platform, but indeed, are globally distributed in Ediacaran shales”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Hofmann, 1992
- Not checked yetcites Martin et al., 2000
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Modern Thioploca are filamentous and have thin organic sheaths marked by longitudinal striations”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Subsequent oxidation 9 would account for the rust-red coloration and presumptive change in oxidation state of templating iron.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“that may be original structures”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, we hypothesize that the original organisms had cylindrical bodies.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
hedged- Asserted: fails — The authors may not put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The authors may not put it forward as true.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The Nama tubes were buried by discrete pulses of sediment influx, each millimeter-scale lamina consigning the tubes beneath it to death and shielding their remains from oxidation.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
In the paper
“Vendotaenia antiqua has commonly been interpreted as an alga”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Gnilovskaya, 1983
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Early diagenetic pyrite formation is commonly associated with bacterial sulfate reduction in conjunction with locally high levels of reactive iron”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
What the sources say
- Not checked yetcites Raiswell and Canfield, 1998
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
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Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“Vendotaenia is described as having compressed tube-or ribbon-like thalli with rare branching and longitudinal fibrous textures; tube widths range from 0.25-3.5 mm”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Gnilovskaya, 1971
- Not checked yetcites Gnilovskaya, 1983
- Not checked yetcites Gnilovskaya, 1990
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the absence of additional character information, we leave V. antiqua among the problematica, but consider an algal interpretation reasonable.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Droser and others (2005) have proposed that many structures reported as Ediacaran trace fossils are actually the casts and molds of tubular bodies”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > INTRODUCTION
What the sources say
- Not checked yetcites Droser et al., 2005
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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Probably not a substantial claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“both features are consistent with Nama and other Vendotaenia fossils”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“but, in life, were presumably longer, as no definitively complete fossils were found”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Tubular and ribbon-like fossils found in the Nama formation and other localities may include large prokaryotes, but most probably represent algae or metazoa.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Work in progress suggests the presence of both vendotaenids and sabelliditids, with examples of the latter only occurring in the upper part of the series”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Vidal et al., 1994
- Not checked yetcites Contreras Sanchez et al., 2006
- Not checked yetcites Jensen et al., 2007
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Another morphological analog is provided by the green alga Enteromorpha, a cylindrical variant of the Chlorophyte Ulva (Figure 10), although such algae probably have a relatively low preservation potential.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“The walls of brown algae contain high amounts of the polysaccharide alginate (Chizhov et al., 1999), a viscous gum that could potentially allow for preservation under conditions of rapid burial.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Chizhov et al., 1999
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“However, the Laminariales, the phaeophyte order to which Chorda belongs, are thought to have diverged only in the Cenozoic, making direct comparison with Ediacaran fossils difficult”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Graham and Wilcox, 1999
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Other carbonaceous tubes from the Doushantuo formation, the Chengjiang Formation, and coeval material from Eastern European cores bear resemblance to the Nama tubes as well, especially longitudinally striated material from the Perevalok Formation of the Central Urals”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Grazhdankin et al., 2007
- Not checked yetcites Xiao et al., 2002
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Chorda occurs in shallow marine environments and consists of long, narrow, flexible fronds that attach to the sea floor by means of a holdfast, with unbranched fronds reaching two to three meters in length.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Graham and Wilcox 1999
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Several of these could be synonymous, but clearly, more than one type of organism contributed to the tubular compressions in Ediacaran rocks from European Russia.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Some specimens show signs of folding, but no evidence of branching”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Xiao et al., 2002
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“In the latter mode of preservation there is a strong similarity to simple trace fossils and it is possible that some of the trace fossils reported from these strata are instead three-dimensionally preserved tubular organisms”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Jensen et al., 2005b
- Not checked yetcites Jensen et al., 2006
- Not checked yetcites Jensen et al., 2007
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Tubes of S. yunnanensis are 0.2-0.35mm wide and inferred to be flexible.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Xiao et al., 2002
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Sabellidites and the Vingerbreek fossils are similar: both are long, thin, and unbranched compressed fossils of hypothesized originally cylindrical bodies.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Sokolov, 1972
- Not checked yetcites Korkutis, 1981
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“No perfect modern analogs exist, but various extant algae exhibit morphologies consistent with both groups of Nama tubes.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“The fossils reflect various modes of preservation, including carbonaceous films and phyllosilicate casts, as well as sediment-filled ridges and grooves”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Contreras Sanchez et al., 2007
- Not checked yetcites Jensen et al., 2007
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“Macroscopic carbonaceous tubes occur in pre-Ediacaran successions (Hofmann, 1992), but rarely in the abundance 13 observed in Ediacaran rocks.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Hofmann, 1992
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Tubular fossils occur in great abundance in dark mudstones and fine sandstones and are the only macrofossils present.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Contreras Sanchez et al., 2007
- Not checked yetcites Jensen et al., 2007
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“On the East European Platform, for example, Gnilovskaya (1988) recognized nine vendotaenid genera, differentiated by size, branching pattern and/or surface texture.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Gnilovskaya, 1988
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“S. yunnanensis has been compared to both cyanobacterial sheaths and laminarian brown algae such as Chorda”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Hou et al., 2004
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Moreover, the Cambro-Ordovician expansion of diverse macroalgae and invertebrate benthos across platform and shelf environments concomitantly reduced the seafloor space available for colonization by tube organisms.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Increasing geochemical 18 evidence suggests that subsurface water masses were commonly anoxic until 580-560 million years ago, with episodic recurrence of oxygen deprivation even later”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Fike et al., 2006
- Not checked yetcites Canfield et al., 2007
- Not checked yetcites McFadden et al., 2008
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Both macroscopic and demonstrably multicellular eukaryotes first appeared well before the Ediacaran Period (Hofmann, 1992;Butterfield, 2000), but the delayed expansion of diverse, macroscopic algae and macroscopic animals (Xiao et al., 2004;Narbonne, 2005) occurred only in concert with rising oxygen tensions in the Ediacaran atmosphere and oceans”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Hofmann, 1992
- Not checked yetcites Butterfield, 2000
- Not checked yetcites Xiao et al., 2004
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“At the same time, Late Neoproterozoic oxygenation dramatically changed the nitrogen cycle, enabling nitrate abundances to build up throughout the oceans.”
- Also stated in: § Phylogenetic Affinities and Global Distribution. · plain
“time, Late Neoproterozoic oxygenation dramatically changed the nitrogen cycle, enabling nitrate abundances to build up throughout the oceans.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Anbar and Knoll, 2002
- Not checked yetcites Knoll et al., 2007
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Also stated in: § Phylogenetic Affinities and Global Distribution. · plain
None of the sources cited for this claim have been checked yet.
In the paper
“There is no reason to believe that taphonomy governed this opening, as macroscopic compressions are commonly preserved in Proterozoic shales”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Hofmann, 1992
- Not checked yetcites Butterfield, 2003
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“This circumstance would also have favored the expansion of eukaryotic photoautotrophs across continental shelves and platforms (Anbar and Knoll, 2002;Knoll et al., 2007).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Anbar and Knoll, 2002
- Not checked yetcites Knoll et al., 2007
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The Vingerbreek locality does include specimens preserved as raised ridges (Figure 4.3), which, if found in isolation, might well be interpreted as simple trace fossils.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
hedgedconditionalSingle case- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Feldschuhhorn tubes show several morphological features that immediately distinguish them from trace fossils, including the presence of folds and elevated levels of carbon (Figures 3.5, 7.2).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The morphological features used to distinguish body fossils from trace fossils (folds, elevated carbon) are reliable indicators of body fossil affinity.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Moreover, under SEM, multiple specimens from the Feldschuhhorn Member show distinct longitudinal striations interpreted as pleats or folds, again indicating a pliant wall composition (Figure 6.3).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“In the Vendian succession of the East European Platform, compressed tubes occur predominantly in the Kotlin horizon, above the regional record of conventional Ediacaran fossils (Gnilovskaya et al., 1988).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Additional information
What the sources say
- Not checked yetcites Gnilovskaya et al., 1988
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We favor an algal interpretation for the Feldschuhhorn population of V. antiqua based on their morphology, while the Vingerbreek tubes remain more enigmatic.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Additional information
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“In modern marine systems, primary production rates in macroalgal communities range from 1.75 to 14.6 kg/m 2 /yr (Graham and Wilcox, 1999), rates equal to or greater than those in the most productive terrestrial plant communities.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Ecological Significance. -While they lack the charismatic features of the contemporaneous
What the sources say
- Not checked yetcites Graham and Wilcox, 1999
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“These are interpreted as either seamless branching flattened in two dimensions-i.e., where the main body of the tube is folded over the branching tube-or as a stem -like junction.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The authors state this as an assumption.
Width is a proxy for age in Nama tube populations.
“Assuming width is a proxy for age”
The paper relies on this without support.
Thioploca is not known to display branching.
“Moreover, Thioploca is not known to display branching.”
The paper relies on this without support.
High-density populations of macroscopic tubes such as those preserved in Nama shales have not been reported from pre-Ediacaran successions and are not much in evidence after the Cambrian Period.
“-While carbonaceous macrofossils are known throughout the Proterozoic record, high-density populations of macroscopic tubes such as those preserved in Nama shales have not been reported from pre-Ediacaran successions; nor are they much in evidence after the Cambrian Period.”
The paper relies on this without support.
The global distribution of tubular compression fossils reflects original widespread expansion of macroscopic organisms in Ediacaran oceans rather than taphonomic or sampling bias.
“Regardless of taxonomic affinity, the global distribution and sudden appearance of such tubes signal a widespread expansion of macroscopic organisms in basinal environments of Ediacaran oceans.”
The paper relies on this without support.
Modern macroalgal primary production rates are applicable to Ediacaran tubular macroorganisms.
“In modern marine systems, primary production rates in macroalgal communities range from 1.75 to 14.6 kg/m 2 /yr (Graham and Wilcox, 1999), rates equal to or greater than those in the most productive terrestrial plant communities.”
The paper relies on this without support.
The morphological features used to distinguish body fossils from trace fossils (folds, elevated carbon) are reliable indicators of body fossil affinity.
“Feldschuhhorn tubes show several morphological features that immediately distinguish them from trace fossils, including the presence of folds and elevated levels of carbon (Figures 3.5, 7.2).”
The paper relies on this without support.
The absence of annulations in examined specimens indicates a true absence of annulations in the organisms, not a preservational artifact.
“Additionally, the lack of annulations in dozens of specimens examined from each locality and the faint and superficial quality of those observed emphasizes the possibility that those seen in isolated specimens could be preservational artifacts.”
The paper relies on this without support.
The Nama tube fossils are representative of Ediacaran tubular macrofossils globally.
“The consistent presence of tubular compression fossils in tens of meters of section in the Nama Group and in numerous other globally distributed localities indicates that these organisms were a significant component of Ediacaran biomass and may prove to be the most abundant macrofossils in the Ediacaran system as a whole.”
The paper relies on this without support.
The oxygen gradient and nitrogen cycle reconstructions from cited works apply to the Ediacaran Nama Group settings.
“Thus, the global expansion of tube fossil populations in Ediacaran oceans is consistent with our understanding of Neoproterozoic environments and evolution.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“Although the exact mineralogy remains uncertain, a phyllosilicate seems likely (Callow & Brasier, 2009; see also Cohen et al., 2009).”
From Remarkable preservation of microbial mats in Neoproterozoic siliciclastic settings: Implications for Ediacaran taphonomic models (2009) · cites this paper as Cohen et al., 2009
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Rivas, A., Myrow, P. M., Smith, E. F., Nelson, L. L., Briggs, D. E. G., & Tarhan, L. G. (2024) · Palaios · doi:10.2110/palo.2024.007 · Cited by 5
Una biota transicional Ediacárica–Cámbrica en el anticlinal de Abenójar (Macizo Ibérico, España)
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Ediacaran-type vendotaenid macroalgae in an Ordovician Lagerstätte
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Chen, K., Yang, A., Bouougri, E. H., Zhao, F., Hu, C., Pan, B., Yang, C., Chen, B., He, T., Sun, X., et al. (2025) · Precambrian Research · doi:10.1016/j.precamres.2025.107882 · Cited by 3
Flabellophyton: The Benthic Macroalgal Fossils in Marwar Supergroup, India
Parihar, V. S., Chouhan, H. R., Kumar, P., & Harsh, A. (2024) · Journal of the Geological Society of India · doi:10.17491/jgsi/2024/173888 · Cited by 3
Middle Ura Association of Organic-Walled Microfossils: the Lower Vendian of the Patom Basin, Siberia
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Lonsdale, M. C., Moore, K. R., Webb, L. C., Schildbach, M., Livi, K. J. T., & Smith, E. F. (2025) · Palaios · doi:10.2110/palo.2024.027 · Cited by 3
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Self-citationPrecambrian ribbon structures of the Grand Canyon, Arizona
Hagadorn, J. W., & Dehler, C. M. (2026) · Precambrian Research · doi:10.1016/j.precamres.2026.108058 · Cited by 1
From Molecular Biology to Geology: A Surprising Trajectory
Abelson, J. N. (2009) · Journal of Biological Chemistry · doi:10.1074/jbc.x109.076836 · Cited by 1
Self-citationMiddle Ura Association of Organic-Walled Microfossils: The Lower Vendian of the Patom Basin, Siberia
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Etemad‐Saeed, N., Anderson, R. P., Tosca, N. J., Bergmann, K., & Knoll, A. H. (2024) · Palaeogeography Palaeoclimatology Palaeoecology · doi:10.1016/j.palaeo.2024.112084
Self-citation
Metadata
- Authors
- Cohen, P. A., Bradley, A., Knoll, A. H., Grotzinger, J. P., Jensen, S., Abelson, J., Hand, K., Love, G., Metz, J., McLoughlin, N., Meister, P., Shepard, R., Tice, M., & Wilson, J. P.
- Affiliations
- Harvard University (US)
- California Institute of Technology (US)
- Universidad de Extremadura (ES)
- University of California, Riverside (US)
- University of Bergen (NO)
- Max Planck Institute for Marine Microbiology (DE)
- University of California, Davis (US)
- Texas A&M University (US)
- ORCID
- Venue
- Journal of Paleontology
- Publisher
- Cambridge University Press (CUP)
- Published
- 2009-01
- Volume
- 83
- Issue
- 1
- Pages
- 110-122
- ISSN
- 0022-3360 (ISSN-L)
- 1937-2337
- OpenAlex
- W2105328483
- Cited by
- 71
- References
- 56
- Citations by year
- 2026: 4 · 2025: 3 · 2024: 5 · 2023: 3 · 2022: 4 · 2021: 7 · 2020: 8 · 2019: 1 · 2018: 7 · 2017: 4 · 2016: 4 · 2015: 2 · 2014: 5 · 2012: 6
- FWCI
- 2.02
- Type
- journal article
- Language
- en
- Open access
- green
- nrs.harvard.edu
- Locations
- Journal of Paleontology (publishedVersion)
- Digital Access to Scholarship at Harvard (DASH) (Harvard University) (submittedVersion, cc-by)
- CaltechAUTHORS (California Institute of Technology) (submittedVersion)
- BioOne Complete (BioOne) (submittedVersion)
- Max Planck Digital Library (submittedVersion)
- MPG.PuRe (Max Planck Society) (submittedVersion)
- Funders
- National Science Foundation (ECS- 03-35765, 0335765)
- Agouron Institute
- Topics
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Evolutionary Biology
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Evolution and Paleontology Studies
- Keywords
- Ediacaran, Nama Group, soft-bodied fossils, early animal evolution, Namibia
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-10-08, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-10-08 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
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