knots of an enigmatic
discovery of an unexpected big detail somehow related to the
twice enigmatic Nematoplexus
 known for its unique spirals dates back to only about 3 years
Chert News 71).
The spiralling tubes of this rare fossil,
described in  under the heading Enigmatic
Organisms, are supposed to be produced
inside "branching knots" although tube branching
has never been seen there.
Most often, knots are found in areas with scattered spirals
(Figs.1,2). Less often, solitary
knots of various aspect are found in areas where regular spirals
absent (Figs.3-9) but usually not far away in the chert sample.
The solitary knots add to the mystery surrounding Nematoplexus.
to these knots are tubes
differing in shape and size from the "normal" spirals with their
remarkably constant curvature and twist, for reasons unknown. The much
bigger tubes and
related knots seen in the three images below right are quite
surprising for their features:
- tube diameters >20Ám, 30Ám at the base,
- tubes nearly straight or slightly curved,
- found only in samples with the usual Nematoplexus
spirals and parts thereof seen in pale bluish chalcedony;
big dark "branching knot", small one near the middle of the image. Note
that there is a spiral with three turns above the knot on the left and
another one right of the middle, with one tangent of the spiral
incidentally being perpendicular to the picture plane so that the
spiral looks like an inclined "3". Width of the picture 1.73mm.
Figs.2-9: "Branching knots" of
various aspect, with or without spiralling tubes nearby. Same scale as Fig.1, width
of the pictures 1.38mm.
With the circular cross-sections of the cut-off big tubes in
the last image clearly seen, the question suggests itself
what the onsets of
the tubes inside the knot do
Are they all interconnected or do
they grow from separate points ? Apparently there is no answer
to simple questions of this kind at present.
Individual non-spiralling tubes, often slightly bigger than those of
the nearby spirals, are
seen as stubs in Figs.1,2. These irregular tubes may show annular
or spiral wall patterns. Perhaps the non-spiralling tubes in the images
on the left belong to this type.
Dozens of tubes with patterned wall have been found loosely arranged in
translucent cluster resembling Nematothallus
Chert News 107),
only millimeters away from the typical Nematoplexus
but in no way connected to the latter.
As another extension of the Nematoplexus
enigma, the regularly wound spirals, too, are occasionally
seen with distinctly differing sizes, even at the very same spot
of the sample (Rhynie
Chert News 106,
there Fig.2). Also it appears that tubes with
diameters smaller than
those of the regular spirals can be weakly curved or nearly straight,
like the one seen crossing the last image here. Furthermore, very thin
slightly curved tubes (4Ám ?) apparently come out of the big black
One may wonder how the various details thought
to be parts of Nematoplexus
can possibly be mutually compatible so that they can be regarded as
aspects of one species. Otherwise they might represent different
species grown very near to each other in places attracting
nematophytes. One might even suspect that different nematophytes could
have more or less united to form a kind of symbiosis.
In view of the variety of structural features associated with Nematoplexus, it
be expected that this nematophyte will yield more surprises
with more finds turning up in Rhynie chert samples stored in
Samples from own collection:
Rh6/102 (0.03kg) found by
Weiss in 2003: Figs.1,5,7;
Rh9/86 (0.28kg) own find in 2003, Part
2: Figs.2,4,6,8 (left
column of images);
Rh15/79 (0.27kg) obtained from Barron
in 2014, Part 1: Fig.9, Part 2: Fig.3.
On the fragmentary remains of an organism referable to the
nematophytales, from the Rhynie chert, Nematoplexus rhyniensis.
Trans. Roy. Soc. Edinburgh 65(1961-62), 79-87, 2
(Scale error on Plate
I Fig.1: not x19 but x1.5)
 T.N. Taylor,
E.L.Taylor, M. Krings: Paleobotany, Elsevier 2009.