misconceptions

Plant cross-section in Rhynie chert with fungus-induced anomaly

Misconceptions

This part of Chert News is a selection of presently still prevailing or recently conceived examples of misinterpretations, erroneous views, unsubstantiated hypotheses, flawed logic, or simply poor judgement in matters somehow related to fossils, and in connection with fossils also to biology, geology, and physics.
It is a cause of concern that most of them have been encountered in the scientific literature, which means they have passed the usual manuscript review procedure unnoticed. There seem to be a lot of them as I did not specially look for them but stumbled upon them while dealing with and wondering about fossils.
Listing the misconceptions is meant to serve more than one purpose: First, they must be removed anyway sooner or later, second, they are to be analyzed and turned into a memorable means of learning how to avoid the like, and third, those who concocted them will hopefully be more careful now that they know they are watched by outsiders.
Like the other parts of Chert News, this part will be filled up in the course of time but, sadly, perhaps never be finished.

See also "The hearsay principle in science", which tries to explain why some of the misconceptions persist in the scientific literature.

Misconceptions related to the following subjects are discussed below:

The images are linked to text

   "Oribatid mite coprolites"
    Tracheid wall reinforcements
   Prototaxites as liverwort carpet rolls
   Cracks mistaken for biological structures
Growth anomaly mistaken for cracks
    Chert formation
    Flint formation
    Scolecopteris, the "maggot fern"
    "Fossil charcoal"
(more will follow)

Oribatid mite coprolites, mite coprolites, arthropod coprolites, coprolites of "unknown creatures" and "new detritivores"

Oribatid mites, or rather their coprolites, became increasingly popular among palaeontologists in the 1990s. They have been a subject of publications up to now (2015), although in the latter years well-founded doubts and contradictions had been formulated and made known to the scientists interested in coprolites of tiny creatures in fossil plants. The alleged coprolites are quite abundant in the Carboniferous, Permian, and Triassic but the related mites have remained elusive. The clots are often angular, and if so, their sizes and shapes agree with those of nearby cells, as if they were casts of the cell lumen, which suggests an origin quite different from that one hitherto assumed. Some of the clots are found inside intact cells where no mite could have deposited them. Clots in silicified wood show a tendency to come in files equalling the cell files of the "eaten" wood. Apparently, those who did not notice these facts and their implications were guided by wishful thinking and superficiality. As a consequence, probably most of the related publications are erroneous. Nevertheless, dubious Palaeozoic oribatid mite coprolites are taken for real in a recent monograph [1], p.425. Also in [1], Fig.11.192 is interesting in this connection as it possibly shows big real coprolites along with much smaller false ones in a Jurassic fossil. It will be thoroughly analyzed later.

Fossil evidence in connection with this subject is presented in "Oribatid mite coprolite sightings – a transient craze ? " and in Rhynie Chert News 28 . The contributions "Alleged coprolites of unknown creatures ..." and "Elusive creatures in fossil wood" are about false coprolites and frass galleries.
A recent paper meant to be about oribatid mite coprolites, if closely inspected for dubious details, provides a picture gallery of evidence belying its title, as pointed out in "Dubious oribatid mite coprolites once more: Comment on Z. Feng et al. (2010)".
Not only size and shape of the clots but their variability, too, indicates an immediate relation to the plant cells, as seen in "Antarctic shit". Contrary to clear evidence, angular clots of highly variable size in Australoxylon are called spherical and uniform.
The clots may even be the only remnants of tissues completely decayed and thus may preserve information on the sizes and shapes of the cell lumina.
Plain criteria are available for separating the real coprolites from clots erroneously described as such in the scientific literature, as pointed out in "Alleged arthropod coprolites re-interpreted". More evidence is discussed in "Palaeozoic wood rot mistaken for oribatid mite coprolites". See also Fossil Wood News 18, 20, 23, 24.

The ideas underlying these comments have been compiled once more on a separate page, "Wood rot or coprolites ?"

[1] T.N. Taylor, E.L. Taylor, M. Krings: Paleobotany, Elsevier 2009.

On the purpose of tracheid wall reinforcements

"In extant vascular plants, water-conducting cells have differentially thickened cell walls (provided by lignin) which mechanically reinforce the cell wall from collaps as a consequence of negative internal pressure created when fluid moves rapidly through a tube." [1]
Sounds reasonable ? (except for the cell walls reinforcing the cell wall.) If you agree, you, too, are inflicted with a widespread misconception which forms as a result of poor teaching: pressure coupled to velocity. Consider this: A fluid can be made to move through a tube at any pressure and velocity. The two parameters can be set independently, which can be easily imagined.
If so, where does the misconception come from ? It comes from a special case considered in hydrodynamics teaching: a tube whose diameter varies along its length. In such tube, the pressure is lower where the tube is narrower and the flow is correspondingly faster. This fact tends to become separated from its preconditions, and hence to be remembered as "rapid flow means low pressure". Its application to plants is utterly absurd: One can easily imagine that the water flow in plants is extremely slow, all the more so in the first land plants with heights of a few centimeters to which the above quotation is meant to apply. Those who can imagine a water flow inside plants rapid enough to produce dynamic pressure effects are liable to producing more absurd ideas.

By the way, treatises on water transport in plants should always be looked at critically. Judging from a few examples, the percentage of erroneous ones may be considerable.
There are more signs of sloppiness in the monograph [1]: Figs. 3.13 and 3.14 are the worst drawings of Aglaophyton and Rhynia in the recent literature. Furthermore, the diameter of Rhynia stems is given as 2-3cm instead of 1-2mm !

[1] K.J. Willis, J.C. McElwain: The Evolution of Plants, Oxford University Press 2002, p54.

Prototaxites as liverwort carpet rolls

The huge enigmatic fossil Prototaxites superficially resembling petrified tree trunks but lacking wood inside has given rise to various interpretation attempts, as compiled in [1]. The latest and seemingly most inventive one appeared in early 2010 [2]. It has been rejected in an oral presentation [3] and by comments based on other arguments appearing shortly later in print [4,5]. However, Graham et al. [6] stick to their hypothesis so that it is worth while presenting the case here.
A concise version of the argumentation in [3] is separated here into two parts, based on the Silurian /Lower Devonian fossils Nematothallus (see Rhynie Chert News 38) and Cosmochlaina (see Rhynie Chert News 41), with a common conclusion: In view of lacking evidence for Silurian liverworts, the most recent interpretation of Prototaxites as rolled-up liverwort carpets turns out to be unsubstantiated.
The incredible Prototaxites /liverwort connection is part of a closely related misconception which has entered into [7], chapter on bryophytes: There it is proclaimed that "One interesting hypothesis suggests that several of the enigmatic ... nematophytes may represent remains of ancient liverworts ... . ... At least some of the tubular aggregations assigned to nematophytes have been reinterpreted as ... liverwort rhizoids, ... ." That hypothesis is also refuted in Rhynie Chert News 41.

[1] http://www.xs4all.nl/~steurh/

[2] L.E. Graham, M.E. Cook, D.R. Hanson, K.B. Pigg, J.M. Graham: Structural, physiological, and stable
    carbon isotope evidence that the enigmatic Paleozoic fossil Prototaxites formed from rolled liverwort mats.
    Am. J. Bot. 97(2010), 268-275.
[3] H.-J. Weiss : Nematothallus: How the filaments produced a cellular cuticle.
8th European Palaeobotany - Palynology Conference, July 2010, p 253.
[4] T.N. Taylor, E.L. Taylor, A-L. Decombeix, A. Schwendemann, R. Serbet, I. Escapa, M. Krings :
    The enigmatic Devonian fossil Prototaxites is not a rolled-up liverwort mat: Comment ...
    Am. J. Bot. 97(2010), 1074-1078.
[5] G.K.Boyce, C.L. Hotton : Prototaxites was not a taphonomic artifact.
    Am. J. Bot. 97(2010), 1073.
[6] L.E. Graham, M.E. Cook, D.R. Hanson, K.B. Pigg, J.M. Graham:
    Rolled liverwort mats explain major Prototaxites features: Response to commentaries.
    Am. J. Bot. 97(2010), 1079-1086.
[7] T.N. Taylor, E.L. Taylor, M. Krings: Paleobotany, Elsevier 2009.

Cracks mistaken for biological structures

A few cases of fossil cracks misinterpreted as cell walls, or crack patterns as epidermis patterns, have been found incidentally. Probably there are more of such. One of them, see Rhynie Chert News 8, may serve as a means to illustrate a deplorable practice in parts of palaeobotany. Shrinkage cracks in chalcedony had been offered in [1,2] as evidence for unusual cell division in the epidermis. D. Edwards and H. Kerp got informed about the error in 2005 but did not acknowledge the information. In 2008, H. Kerp presented another photograph on the same subject, with lower magnification so that the cracks were not visible, without retracting his former misinterpretation of the cracks. This picture is now seen in Palaeobotany [3] as Fig.8.50, also without a proper comment indicating that it is to replace the misinterpreted picture in [1,2].
What is deplorable here is that professional palaeobotany proved unable to correct itself. The error in [1,2] has never been addressed or retracted so that it remains a source of desinformation to students kept in the belief that they can trust what they read in reputable scientific journals.
Another example, without improper behaviour of those involved but with far-reaching consequences, is the interpretation of the net-like structured cuticle Cosmochlaina as the replica of an epidermis. See Rhynie Chert News 41.
Black petrified wood with conspicuous crack patterns or as small fragments in chert is liable to be mistaken for fossil charcoal [4]. See Fossil Wood News 9
Shrinkage cracks on the surface of a petrified tree trunk have been mistaken for arthropod burrows [4]: See Fossil Wood News 16
A brief comparison of various polygonal structures is to caution against misinterpretations.

[1] W. Remy, H. Hass : New information on gametophytes and sporophytes of Aglaophyton major and inferences ...
Rev. Palaeobot. Palynol. 90(1996), 175-193.
[2] D. Edwards, H. Kerp, H. Hass: Stomata in early land plants,
J. Exp. Botany 49(1998) Special Issue, 255-278.
[3] T.N. Taylor, E.L. Taylor, M. Krings: Paleobotany, Elsevier 2009.
[4] R. Rößler: Der versteinerte Wald von Chemnitz. Museum f. Naturkunde Chemnitz 2001.

Growth anomaly mistaken for cracks

Damage to the tissue of Lower Devonian plants is a common sight in the Rhynie chert. Most often it cannot be assigned to a known cause but in some cases one cause can be excluded, as in the case pictured here and at the top of this page. The radially arranged fissures or wide gaps had been described as shrinkage cracks due to decay but there are features indicating that they were formed in the live plant.
See Rhynie Chert News 4, 21, 54, 117,

Chert formation

Several textbooks on geology and petrography provide poor information on chert formation, although it is well known that cherts may yield fossils whose quality compares with that of amber fossils.

Therefore it is deplorable that a publication of the Naturkunde-Museum Chemnitz describes chert formation in a way that does not apply to the cherts of highest scientific interest: "Cherts ... are phenomena which formed only after deposition of the surrounding rocks. Silica gel cements or partially displaces the rock ..." [1]. (For original text see German version.) The authors should have known better: All chert samples presented at the yearly Chert Workshop at the Naturkunde-Museum Chemnitz, also those described at www.kieseltorf.de and www.chertnews.de, formed in other ways, by silicification of peat, mud, or water.
An impressive example for the silicification of plain water is seen in Rhynie Chert News 23 . See also "chert formation".

Image: Evidence for water turning into chert

[1] R. Rößler, T. Zierold, F. Spindler, F. Rudolph : Strandsteine ...
Veröff. Mus. Naturkunde Chemnitz 30(2007), 5-24.

Flint formation

"There are always small pores between the individual grains of sand or chalk. Watery solutions are moving about these cavities." [1] (For original text see German version.) This seemingly plausible statement is to explain the transport of dissolved SiO2 which finally becomes flint. Here we have the once favourite idea of substance transport by "circulating solutions", which is certainly right if there is really a cause driving a flow. Within the thick deposits of chalk mud on the bottom of the sea floor, however, no such cause is evident.
It is well known that substances can move without any flow, by diffusion. This works even in compacted sediments without any liquid-filled cavities, along the grain boundaries. This fundamentally different mode of transport, which easily explains various phenomena, is found hard to understand by some, and therefore not included into their considerations so that they have to invent additional assumptions like liquid flow. In the present case, a written comment provided to the authors [1] in due time before print had been ignored.

[1] R. Rößler, T. Zierold, F. Spindler, F. Rudolph : Strandsteine ...
Veröff. Mus. Naturkunde Chemnitz 30(2007), 5-24.

Scolecopteris, the "maggot fern"

The remarkable and amusing maggot fern story begins in the second half of 18th century and has been fraught with misinterpretations and incompatibilities ever since. A very concise introduction leading over to problematic recent finds is given here.

Scolecopteris sporangia arranged into synangia

An awkward desire to see symmetry at work even where there is none has led to repeated statements about "radial" and "bilateral" symmetry of sporangia arrangement, combined with attempts to find causes for the often observed absence of symmetry. The whole symmetry discussion concerning Scolecopteris sporangia arrangement is rather vain, as pointed out in "Conspicuous in the chert - synangia of Scolecopteris". (See also "The hearsay principle in science".)
As a characteristic feature of marattialean ferns, fossil and extant, the sporangia are fused into entities called synangia attached to the pinnule with a short stalk or pedicel, which may be so short that it is hardly visible. Led by the wish to see the characteristic stalk, the conducting strand laid bare by the decay of tissue had been and sometimes still is mistaken for a stalk.
Recent publications on the maggot fern from Döhlen Basin are inconsistent with respect to the venation pattern of the pinnules which suggests the presence of more than one species, contrary to claims that there is only one. Indications of the presence of more species in Döhlen Basin come also from several other observations, including hairy sporangia. This is not surprising in view of the fact that 26 Euramerican Scolecopteris species had been distinguished by 1996 [1], and their number will very likely increase.

[1] M.A. Millay: A review of permineralized Euramerican Carboniferous tree ferns. Rev. Palaeobot. Palyn. 95(1997), 191-209.

Fossil charcoal

array of degraded wood blocks, no charcoal

Fossil charcoal has become a favourite interpretation of silicified wood with black and brittle aspect, especially if the fragments are embedded in white or red chalcedony [1]. Permian tree trunk sections with such features make beautiful exhibits at the Naturkunde-Museum Chemnitz, where a piece of extant tree trunk with charred surface has been put up for comparison.
Closer inspection revealed that most probably there is no charcoal involved. Related arguments were not disproved but repeatedly ignored.
For fossil charcoal publications and contrary argumentation see Fossil Wood News 9, 17.

Addendum 2015: After about ten years of stubborn ignorance in view of plain evidence, and after having promoted the silicified charcoal hypothesis despite of repeated warnings for an even longer time, the involved authors seem to have grasped the essentials now and present them as if they had thought up the true explanation by themselves.

[1] R. Rössler: Der versteinerte Wald von Chemnitz. Museum für Naturkunde Chemnitz, 2001, 179.

more will follow

Site map
Chert News

other
Errors and Mistakes

German / deutsch