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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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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
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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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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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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.
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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
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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
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- Also stated in: § Preserved Morphology. · boosted
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In the paper
“Vingerbreek specimens have more robust annulations”
§ 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
“but the older Vingerbreek populations 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
“Based on EDAX peak locations and values, internal molds of Feldschuhhorn fossils consist primarily of iron-rich phyllosilicates, including chlorite, with a minor feldspar component occasionally present”
§ 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
“Fossils in both assemblages are commonly preserved as partially compressed internal molds”
§ 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
“The ribbon-like compressed tubes show little evidence of width variation along individual axes.”
§ 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
“No clearly differentiated terminations were observed in hundreds of specimens from both localities.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
boosted- Asserted: passes — The authors put it forward as true.
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In the paper
“One exception to this pattern is seen in the tube fossils preserved as carbonaceous films in the Feldschuhhorn Member (Figure 3.6).These fossils show a broader size 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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In the paper
“Rare specimens from both horizons preserve faint transverse lineations”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
What the sources say
- Not checked yetcites Bradley, 1998
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In the paper
“The most abundant fossils in Nama rocks, these tubes”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
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In the paper
“A number of Feldschuhhorn samples show distinct longitudinal striations”
§ 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
“Vingerbreek tubes and matrix show rough similarity in infill and matrix composition with some significant differences”
§ 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
“Morphological detail is preserved primarily in compressed casts and molds of tube walls”
§ 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
“range in width from 0.6 to 2.1 mm”
- Also stated in: § Preserved Morphology. · plain
“Widths range from 0.6 mm to 2.1 mm”
§ 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
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 tubes are preserved mostly as compressed casts and molds”
§ 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
“Feldschuhhorn specimens preserve fine longitudinal pleats or folds”
§ 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
“we know of no well-documented occurrences of densely packed vendotaenid or other tube fossils in rocks older than approximately 555 million years.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
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In the paper
“As noted above, the Vingerbreek tube fossils differ in a number of salient characteristics from Feldschuhhorn V. antiqua populations.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plain- Asserted: passes — The authors put it forward as true.
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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
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In the paper
“Vingerbreek fossils found at the Kliphoek farm at 26 o 45' S 16 o 33' E occur sporadically through approximately 50 m of section in a similar environmental but slightly older stratigraphic context (Figure 2.2).”
§ 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
“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.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > CONCLUSIONS
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In the paper
“No comparable pattern is evident in Vingerbreek specimens.”
§ 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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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
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“However, a single locality in the Feldschuhhorn Member contains tubes preserved by thin carbonaceous films, detected using low voltage EDAX (Figures 3.6, 7.2, 8.4).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
plainSingle case- Asserted: passes — The authors put it forward as true.
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In the paper
“EDAX mapping of Mg shows covariation with Fe on a fine spatial scale, suggesting that Mg may be present in limited solid substitution within or absorption on Fe minerals.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“The morphological simplicity of the Nama tube fossils and a general lack of distinguishing 19 features make definitive taxonomic categorization difficult.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > CONCLUSIONS
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“In some cases, distinct lineations separate branches from the main tube wall (Figure 3.5).”
§ 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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In the paper
“Specimens show sinuous bends, indicating that living and recently dead specimens were flexible.”
§ 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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In the paper
“interpreted as taphonomic artifacts formed during compression of originally cylindrical bodies”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
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None of the sources cited for this claim have been checked yet.
In the paper
“both are expected where an influx of fine-grained siliciclastic sediment shields organicwalled organisms from oxygen”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
What the sources say
- Not checked yetcites Zhu et al., 2005
- Not checked yetcites Brock et al., 2006
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Moreover, Thioploca is not known to display branching.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
plain- Asserted: passes — The authors put it forward as true.
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- Rests on an assumption: Thioploca is not known to display branching.
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 interpret the Vingerbreek material as the direct remains of tubular organisms preserved through different pathways.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
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.
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 abundant Feldschuhhorn tubes are assigned to the widespread Ediacaran problematicum Vendotaenia antiqua”
- Also stated in: § Phylogenetic Affinities and Global Distribution. · plain
“Thus, we assign the Feldschuhhorn fossils to Vendotaenia antiqua Gnilovskaya 1971.”
§ 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: passes — The paper’s conclusions depend on it.
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- Also stated in: § Phylogenetic Affinities and Global Distribution. · plain
In the paper
“Such an interpretation, however, breaks down when one considers size: while Thioploca is large by bacterial standards, its sheaths have linear dimensions an order of magnitude lower than those of the Ediacaran fossils even when taking into consideration width expansion due to compression”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Schultz et al., 1999
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Such a conclusion supports the hypothesis that some structures reported as Ediacaran trace fossils are actually the casts and molds of tubular bodies”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
What the sources say
- Not checked yetcites Droser et al., 2005
hedgeddirect- 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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In the paper
“Chlorites in tube fillings may well have originated via diagenesis of smectite group clays, especially in the presence of other iron minerals”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
What the sources say
- Not checked yetcites Eberl et al., 1984 source
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.
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 general similarities in depositional setting and bedding plane distribution between Vingerbreek and Feldschuhhorn tubes also argue in favor of a common interpretation for the two populations.”
§ 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: passes — The paper gives a reason why it holds.
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 high abundances and random orientation of tubes suggest that benthic populations were preserved more or 10 less in place.”
§ 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: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
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
“consistent with a greater degree of time averaging”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
hedgedcorrelationalSingle case- 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.
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 are most easily interpreted as breaks rather than tips”
§ 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: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
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 Feldschuhhorn specimens, we also interpret these as taphonomic artifacts formed diagenetically”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
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.
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
“Morphologically similar compression fossils occur in other Ediacaran and early Cambrian successions, including localities in Spain, the East European Platform, and China”
§ 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: passes — The paper gives a reason why it holds.
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
“consistent with the formation of pyrite crystals that were subsequently weathered out by oxidizing fluids”
§ 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.
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 organisms preserved as Nama tubes had a differentiated external wall or sheath that preserved better than any internal tissues”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Preserved Morphology.
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.
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
“it is sometimes difficult, if not impossible, to distinguish a tubular macrofossil from a simple trace fossil with confidence.”
§ 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: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“These dates bracket the fossils described here.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > GEOLOGIC SETTING
What the sources say
- Not checked yetcites Grotzinger et al., 1995
plaincorrelational- 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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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
“indicating an original construction of strong but flexible organic matter”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
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.
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 record pliant organic walls”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Abstract
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.
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 interpret the apparent time restriction of densely packed tube fossils to reflect the combined effects of evolutionary innovation and taphonomic processes.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
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.
In the paper
“the distinct, finely laminated bedding planes on which Nama tubes occur are a rarity in productive oxic Phanerozoic shelf areas”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Jensen et al., 2005a
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.
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In the paper
“Within the brown algae, for example, Chorda filum bears the most obvious morphological similarity to the unbranched Vingerbreek fossils”
§ 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
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.
In the paper
“Sabelliditids also commonly show distinct transverse laminations that impress upon the encompassing matrix”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Korkutis, 1981
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.
In the paper
“Broad comparisons can be drawn between the Vingerbreek tubes and structures found in a handful of extant metazoan groups, including pogonophoran worm tubes and scyphozoan polyp sheaths”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Babcock et al.,
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.
In the paper
“Within the red algae, intertidal Nemalion bears the strongest morphological resemblance to the Feldschuhhorn tubes (Xiao et al., 2002), with long, occasionally branched fronds.”
§ 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
boostedcorrelational- 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.
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 fossils preserved with apparent faint transverse annulations are consistent with growth along an open apical margin, a kind of growth found only in metazoans.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
hedgedcorrelational- 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.
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
“occur regionally in the Redkino succession wherever off-shore shales are preserved.”
§ 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.
None of the sources cited for this claim have been checked yet.
In the paper
“While the Nama localities preserve a wider range of morphologies and preservation modes than most previously studied areas, diverse tubular fossils recently reported from the latest Ediacaranbasal Cambrian of central Spain are similarly diverse.”
§ 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
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.
In the paper
“Closure of the taphonomic window for dense tube populations reflects the advent of significant bioturbation, especially in deep shore-face environments”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Orr et al., 2003
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.
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
“Comparison with macroalgal analogs appears fruitful when taking into consideration the presence of branching in Feldschuhhorn specimens.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
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.
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
“Consistent with such morphological diversity within the Nama, a global diversity of tubular macrofossils is preserved in other Ediacaran and Lower Cambrian shales.”
§ 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.
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 preserved reproductive structures or other morphological details, however, it would be challenging to differentiate cylindrical fossils of macroscopic green, red, or brown algae.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
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.
In the paper
“The Nama tubes also bear comparison to Sinocylindrica yunnanensis, smooth carbonaceous ribbons found in the Ediacaran Doushantuo Formation and Lower Cambrian Chengjiang Formation of China”
§ 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
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.
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 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.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > CONCLUSIONS
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.
- Rests on an assumption: The Nama tube fossils are representative of Ediacaran tubular macrofossils globally.
None of the sources cited for this claim have been checked yet.
In the paper
“Both algal and metazoan interpretations of the Nama tubes are consistent with current knowledge of the timing of animal and macroalgal evolution in Ediacaran Period (Narbonne, 2005;Xiao et al., 2004;Knoll et al., 2006).”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Additional information
What the sources say
- Not checked yetcites Narbonne, 2005
- Not checked yetcites Xiao et al., 2004
- Not checked yetcites Knoll et al., 2006
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.
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
“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.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Additional information
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.
- Rests on an assumption: The global distribution of tubular compression fossils reflects original widespread expansion of macroscopic organisms in Ediacaran oceans rather than taphonomic or sampling bias.
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
“While they lack the charismatic features of the contemporaneous Ediacaran fauna, tubular fossils such as those from the Nama Group may well be the most common and abundant macrofossils in the Ediacaran Period.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Ecological Significance. -While they lack the charismatic features of the contemporaneous
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.
- Rests on an assumption: The Nama tube fossils are representative of Ediacaran tubular macrofossils globally.
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
“What we lose in the ichnofossil diversity of Ediacaran rocks, we make up in the abundance and taxonomic richness of body fossils.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > CONCLUSIONS
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.
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
“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
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.
- Rests on an assumption: The absence of annulations in examined specimens indicates a true absence of annulations in the organisms, not a preservational artifact.
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
“To the extent that Ediacaran tube organisms were multicellular eukaryotes, colonization of basinal substrates would only have been possible as oxygen partial pressures increased.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
hedgedconditional- 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.
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 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.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > CONCLUSIONS
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.
- Rests on an assumption: The Nama tube fossils are representative of Ediacaran tubular macrofossils globally.
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 features, however, indicate that the fossils were originally carbonaceous.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
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.
In the paper
“Whether algal or animal, documentation of widespread tubular macrofossils supports the hypothesis put forth by Droser et al. (2005) that many of the bedding plane features originally interpreted as simple trace fossils in Ediacaran successions in fact record body fossils of cylindrical or ribbon-like organisms.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > CONCLUSIONS
What the sources say
- Not checked yetcites Droser et al. (2005)
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.
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
“EDAX mapping of Mg shows covariation with Fe on a fine spatial scale, suggesting that Mg may be present in limited solid substitution within or absorption on Fe minerals.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
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.
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
“Specimens show sinuous bends, indicating that living and recently dead specimens were flexible.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Branching Longitudinal striations
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.
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 this respect, it is not the oxygen content of the surface ocean that is of concern as much as oxygen levels in and above the oxygen minimum zone.”
§ 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: passes — The paper gives a reason why it holds.
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, the global expansion of tube fossil populations in Ediacaran oceans is consistent with our understanding of Neoproterozoic environments and evolution.”
§ 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: unclear — It is unclear why the paper says it holds.
- Rests on an assumption: The oxygen gradient and nitrogen cycle reconstructions from cited works apply to the Ediacaran Nama Group settings.
In the paper
“The establishment of a strong oxygen gradient between seawater and subsurface sediments would also have facilitated the expansion of chemoautotrophic prokaryotes that exploit the oxic/anoxic interface (Canfield and Teske, 1995) until bioturbation modified that gradient.”
§ TUBULAR COMPRESSION FOSSILS FROM THE EDIACARAN NAMA GROUP, NAMIBIA > Phylogenetic Affinities and Global Distribution.
What the sources say
- Not checked yetcites Canfield and Teske, 1995
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. 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.
- 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.
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.
- 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.
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.
- 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 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
“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.
- 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 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
“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.
- 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.
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 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.
- 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.
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.
- 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 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.
- 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 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
“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.
- 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.
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.
- 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
“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.
- 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 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
“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.
- 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 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.
- 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
“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.
- 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 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.
- 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
“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.
- 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 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
“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.
- 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
“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.
- 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 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.
- 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 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
“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.
- 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 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.
- 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.
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
“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.
- 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.
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.
- 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
“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.
- 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
“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.
- 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.
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.
- 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 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
“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
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.
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.
- 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
“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.
- 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
“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.
- 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 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.
- 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.
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
Citations
Cites
The interaction of TIGIT with PVR and PVRL2 inhibits human NK cell cytotoxicity
Stanietsky, N., Simic, H., Arapovic, J., Toporik, A., Levy, O., Novik, A., Levine, Z., Beiman, M., Dassa, L., Achdout, H., et al. (2009) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0903474106 · Cited by 3,524
Proterozoic Ocean Chemistry and Evolution: A Bioinorganic Bridge?
Anbar, A. D., & Knoll, A. H. (2002) · Science · doi:10.1126/science.1069651 · Cited by 1,191
Self-citationTracing the stepwise oxygenation of the Proterozoic ocean
Scott, C., Lyons, T. W., Bekker, A., Shen, Y., Poulton, S. W., Chu, X., & Anbar, A. D. (2008) · Nature · doi:10.1038/nature06811 · Cited by 1,098
Late-Neoproterozoic Deep-Ocean Oxygenation and the Rise of Animal Life
Canfield, D. E., Poulton, S. W., & Narbonne, G. M. (2007) · Science · doi:10.1126/science.1135013 · Cited by 1,000 · cited 3×
“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 (Fike et al., 2006; Canfield et al., 2007, 2008; McFadden et al., 2008; Scott et al., 2008; Shen et al., 2008).”
BackgroundOxidation of the Ediacaran Ocean
Fike, D. A., Grotzinger, J. P., Pratt, L. M., & Summons, R. E. (2006) · Nature · doi:10.1038/nature05345 · Cited by 989
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Annual Review of Earth and Planetary Sciences
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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
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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.
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