Funny faces
deutsche Version

In view of the huge variety of fossil shapes it is not surprising that there are a few funny looking ones, which offer the opportunity to present little bits of palaeontological information in a funny way, which may serve as a diversion from the mere intake of facts.
Minky "big mouth": cross-section of partially decayed Nothia
Far left: Minky, Reading 2012

Left: Nothia, Rhynie 400 000 000 B.C.,
Inclined section of this less abundant plant in the Rhynie chert, hollow before silicification owing to partial decay of tissue, with twin central strands as a result of forking, one of the strands seen extending into the dark cavity.
Photograph: H. Sahm.     
fungus-infected plant in Rhynie chert
Far right:  Slightly inclined cross-section of the most common plant in the Lower Devonian Rhynie chert,
Aglaophyton, also known as Rhynia major. This specimen had lost part of its tissue while alive, as can be inferred from the response of the plant seen as the dark line below. What appears as the second "eye" is a spherical body produced by the dense agglomeration of fungus hyphae probably grown in the dead plant. sad face
(The typical aspect of symbiotic fungi growing in live
Aglaophyton is different. See Rhynie Chert News 32.)
Note also the cavities lined with quartz crystals.
 Right: Grieved by the financial crisis.

mock Tempskya white spots in coniferous woodFossil wood of
coniferous type,
patterned by selective silicification,
see Fossil Wood News 2.

Far left: "Mock Tempskya",
detail from a beautifully patterned fossil
coniferous-type wood specimen,
misinterpreted as the Cretaceous fern Tempskya on several Dutch websites,
width of the picture 6.5mm, see Google:
Tempskya determinatie Hans Kerp .

Tempskya is a small tree fern whose trunk consists of several very thin stems and lots of aerial roots, all fused into a composite stem. Hence, its cross-section shows lots of mm-size roundish sections with concentric build. The cross-sections in the above pictures may look concentric  but reveal a texture if looked at more closely.  The cell files seen more or less vaguely in the two images indicate the radial direction of coniferous wood. Misinterpretation of patterned coniferous-type wood by superficial inspection is a common pitfall.
peculiar cracks in coniferous wood
Right: Coniferous-type fossil wood (Oregon) with growth zones of distinctly differential aspect and mechanical properties before silicifcation.
The rhombic cross-sections can be understood as being brought about by a succession of steps involving shrinkage of soft wood, formation of narrow shrinkage cracks, influx and deposition of silica along the cracks so that the crack faces become lined* with stiff silica, vertical compression causing kinking of t
he crack linings* while the soft wood is still soft, further vertical compression pushing the kinked linings* into rhombic shapes, deposition of more silica in the cavities and throughout the wood.  .
More explanations are given in: Fossilien 20(2003), 330.
The polished specimen had been provided by R. 
Henzel, Celle.
*Amendment 2013:  Closer inspection did not produce evidence for the supposed kinking of the conspicuous silica lining. As it seems now, the lateral corners of the cavities were brought about by kinking of the stiff pith rays in soft wood.

5 Trichopherophyton cross-sections, 3 of them within an old envelope
Left: Cross-section of a multiple shoot of an early land plant of the zosterophyll family, either Trichopherophyton or Ventarura. In the scientific literature, similar
sections of these plants have been repeatedly interpreted als new rhizomes incidentally entering decaying ones and growing along inside. However, there is evidence that it is a peculiar growth mode, a veritable invention, apparently by some ancestor of these Lower Devonian plants, which enables the young shoots to make use of the old ones as support and protective sheaths. The like had been re-invented independently several times and is now realized, with leaves instead of shoots, with the onions, for example.


Croftalania venusta as cyanobacterial cover on flooded Horneophyton
Right: Fluffy tufts of the filamentous cyanobacterium Croftalania venusta grown on a flooded and partially decayed shoot of Horneophyton with divided central strand.
The filaments of about 3Ám thickness had grown
on substrates in the flooded habitat, as on dead land plants, upwards towards the light. Considering that the filaments grow independent of each other or in fluffy bunches, the occasionally observed stylish trimming of the "hair" poses a problem to be solved. Evidence has been presented suggesting that the crustacean Castracollis may have produced the clear-cut outline by grazing on the fluffy tufts [1].
Nothia cross-section with bright yellow "eyes"



Left: What looks like a wobbly monster with fiery eyes hiding beneath a shelter is a cross-section of a shoot of Nothia aphylla (see top), shrunken and deformed, with forked central strand. Among hundreds of Nothia sections, some look like faces but those with yellow eyes are quite rare. The surface of live Nothia is bumpy but the coarse shrivelling usually seen on fossil Nothia and often also on other plants in the Rhynie chert is due to extensive decay and  shrinkage of the tissue inside.



shrunken Nothiashrunken Nothiashrunken Nothiadecayed Nothiashrunken Nothia
shrunken Nothiashrunken Nothiashrunken Nothia
The preceding 8 pictures of shrunken Nothia have all been taken from one small sample of Rhynie chert.



  What is called "emoticons" nowadays has apparently been there for 400 million years.
Ventarura cross-section

"Fossil faces" may be funny to look at but the one seen here on the right gave rise to a creepy feeling when suddenly the "owl" began to slowly open one eye. It was an air bubble creeping up from a cavity while the cut half of the chert sample was being observed with a microscope and a drop of cedar oil was put on the polished Ventarura cross-section to conceal scratches left after polishing.
This picture had been shown at the EPPC 2014 [1] and at a related exhibition in the town hall of Padua, with the caption:
 "Be careful! Ventarura is watching you. This may serve as an encouragement to the palaeobotanists to work carefully as if they were watched."
Such
advice is appropriate, judging from the mistakes, errors, and misinterpretations encountered in the palaeobotany literature.

[1]
H.-J. Weiss:  Rhynie chert - Implications of new finds,
      European Palaeobotany and Palynology Conference 2014, Padua.


H.-J. Weiss     2012
, 2013, 2014                More funny faces will appear occasionally.

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