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Lepidophylloides - Scale Tree Leaves - Feathery Or Long?


hitekmastr

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After my original post I learned that the feathery fossils are probably leaves of a scale tree - maybe emergent leaves. They are often described as "similar to conifers" and are feathery as you can see. Are they Lepidodendron leaves or Siggilaria or Calamites?

There are also listings in the literature of "LONG" grass-like leaf appendages coming straight out from the above ground (or above water) trunks of the Lepidodendron tree. How do we tell if the side appendages are long leaves or rootlets?

One type of leaf appendage is often described as coming straight out from the trunk, looking more like grass, and this is confusing. In the fossils we have found, there appear to be rootlets coming out from the underground (or underwater) trunk stems, but in some fossils it looks like the long appendages are coming out from the above-water trunk because they are long and leaf shaped and do not look like rootlets. Interested in references clarifying the leaf types.

The images of small feathery leaves came from cracking open already-thin shale pieces from the St. Clair fossil pits (Llewellyn Formation, Carboniferous/Pennsylvanian, St. Clair, 300-308 mya). The images of the core trunk stems with appendages were excavated from the shale floor of the fossil pit.

An example of the larger specimens showing the appendages coming out from the sides is included - some people believe these are rootlets but they may also be leaves coming out from the trunk....ideas? These files are listed as Lepidodendron but actually if it's a root it is called Stigmaria (which includes roots of Lepidodendron and Siggilaria - if the shoots coming out the sides are LEAVES then they are designated Lepidophylloides).

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Edited by hitekmastr
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Neat piece! Since the whorls are annular, vs on a helical bias, it may not be Lepidodendron. Something related to Calamites, maybe?

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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Annularia, just starting to sprout? :unsure:

Nice piece!

Regards,

    Tim    -  VETERAN SHALE SPLITTER

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Nice specimen!

I'm thinking some species of "Sphenophyllum"?

"Absence of evidence is not evidence of absence"_ Carl Sagen

No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go.

" I think, therefore I collect fossils." _ Me

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes

"can't we all just get along?" Jack Nicholson from Mars Attacks

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Perhaps the squirrels ate the seeds out of a cone? :)

Hmm...you mean those very rare Paleo squirrels...we've been looking for them, too. B)

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hitekmastr.... Thats the difficulty with paleobotany.... Very often your only seeing maybe 2 pieces of a 50 piece jigsaw at any one time which represents only a small portion of the complete tree...Couple that with how trees can develop differently based purely on the variations of enviromental conditions they were growing in (as we see today)... we can soon begin to see how these subtle differences can become confusing and lead us to conclude that many different variations of the same plant were growing at the same time....Then add differences in preservation altering fine detail and decortication prior to fossilisation and during extraction... Were soon looking at many hundreds of variations of the same thing....

To answer your question I think collecting the specimens yourself is going to be beneficial to aid your ID's because you will get a feel for whats what... I remember most Stigmaria I seen with associated rootlets appeared to come from a preserved layer slightly different to the mudstone shales containing the leaf material ...and this layer was very often refered to as ' seat earth '... The fossil soil that the trees grew in...The texture was different as well as the colour and the fossil material was usually limited to roots & rootlets and tree stump bases and crushed fallen trees... No delecate fern fronds were preserved amongst this material...If the same principles apply to the area your collecting then when you begin to recognise this layer you should be able to to start to differentiate between rootlets and foliage...

What helped me understand this was a recent opencast coalmine I collected where they slice through the layers to extract the coal and subsequently you get to see these boundaries revealed like layers in a cake... Heres a couple of photo's illustrating hopefully what I mean... The first photo shows 2 consequtive deposited and fossilised layers of seat earth with the associated fossil tree stump remains visible directly above them... The seat earth contains the stigmaria roots so you get to see them in context in relation to the remains of a growing tree...

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Heres another example I searched out showing a Sigillaria tree stump base and illustrating the more compacted fossil soil ' seat earth ' underneath it...

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Hope this helps....

Cheers Steve... And Welcome if your a New Member... :)

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hitekmastr,

Looking at your pictures, the top two are stigmaria rootlets, the bottom three are Annularia with the leaflet whorls folded close to the stem.

When you find the Squirrels that ate the cones, let me know. We can rewrite the history of Mammals! :)

Thanks for the clarifications...of course, everyone keeps looking for the odd out of place track or bone that throws the fossil record out of whack, but it seldom happens. Maybe we'll find some unknown furry leaves sometime and we can call them mammaloceras...

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hitekmastr.... Thats the difficulty with paleobotany.... Very often your only seeing maybe 2 pieces of a 50 piece jigsaw at any one time which represents only a small portion of the complete tree...Couple that with how trees can develop differently based purely on the variations of enviromental conditions they were growing in (as we see today)... we can soon begin to see how these subtle differences can become confusing and lead us to conclude that many different variations of the same plant were growing at the same time....Then add differences in preservation altering fine detail and decortication prior to fossilisation and during extraction... Were soon looking at many hundreds of variations of the same thing....

To answer your question I think collecting the specimens yourself is going to be beneficial to aid your ID's because you will get a feel for whats what... I remember most Stigmaria I seen with associated rootlets appeared to come from a preserved layer slightly different to the mudstone shales containing the leaf material ...and this layer was very often refered to as ' seat earth '... The fossil soil that the trees grew in...The texture was different as well as the colour and the fossil material was usually limited to roots & rootlets and tree stump bases and crushed fallen trees... No delecate fern fronds were preserved amongst this material...If the same principles apply to the area your collecting then when you begin to recognise this layer you should be able to to start to differentiate between rootlets and foliage...

What helped me understand this was a recent opencast coalmine I collected where they slice through the layers to extract the coal and subsequently you get to see these boundaries revealed like layers in a cake... Heres a couple of photo's illustrating hopefully what I mean... The first photo shows 2 consequtive deposited and fossilised layers of seat earth with the associated fossil tree stump remains visible directly above them... The seat earth contains the stigmaria roots so you get to see them in context in relation to the remains of a growing tree...

post-1630-0-38826600-1347177017_thumb.jpg

Heres another example I searched out showing a Sigillaria tree stump base and illustrating the more compacted fossil soil ' seat earth ' underneath it...

post-1630-0-25113500-1347177154_thumb.jpg

Hope this helps....

WOW - this is EXACTLY what we were wondering about - your description of "seat earth" puts the roots and rootlet fossils we collected in sharp focus. Thanks for your thoughtful explanation! As you so perceptively observed, we're discovering (slowly) that it's important to think about the original ecology of the place we're studying, as well as the layout of the "site" which is how the original specimens ended up being preserved, esp. in relationship to each other. This is in contrast to our original approach which was to randomly stumble on whatever we happen to find at a site.

As we become more experienced fossil hunters, we find ourselves thinking about where the various types of fossils are appearing in the different layers and locations (and geological formations). St. Clair is a great site for this because there are accumulations of trunks, roots and leaves in clusters, in specific locations as you say and it's a very well defined, well-boundaried shale pit with new clusters of fossils revealed literally every week by erosion, fossil pit makers, etc. Just today, Nancy and I were talking about getting some fossil posters for our "fossil room" that show for example Carboniferous forest and the Ordovician/Devonian seas with the flora and fauna, to help visualize the ecology.

Your point about variation is spot on - it's surprising that so much in paleobotany appears to be unresolved - not to mention the confusion caused by assigning different genera based on structure or morphology (leaves, bark, roots of the same/similar species having different genera). Maybe amateur (and professional) paleontology enthusiasts will help to clarify some of this. We feel that spending several Saturdays at St. Clair has helped us to appreciate paleobotany, the missing links in the Carboniferous fossil record especially, and will also inform our site visits when we look for Devonian and Ordovician invertebrates. As "collectors" (we never set out to become "collectors" by the way) - we are looking for unusual specimens, diversity (samples of many species), and also larger and well articulated pieces that make nice displays. It's also a great hobby and provides an appreciation for the lessons of pre-history which we all tend to overlook, today.

I also use fossils in my profession (directing a university research program). Last week, I gave a presentation on "radical innovation" to a group of analysts in Washington and I used some fossil photos and extinction events to make the point that global climate change is creating the conditions for a massive extinction event (which is already underway and well documented) - I mentioned that the extinction events that wiped out 22,000 species of trilobites and virtually all fern trees were accompanied by major changes in oxygen and CO2 levels. I noted that CO2 levels have risen from 380 ppm to 400 ppm in less than a decade and when it reaches 550 ppm we will have difficulty breathing when we go outside. So there are lessons for the present and future from studying fossils and in particular, extinction events.

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Thanks for the link... I will have a look at the other specimens...Glad I could help...Enjoy your journey into paleobotony... I'm looking forward to picking it up again myself, sometime soon....

Cheers Steve... And Welcome if your a New Member... :)

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PS... I think this image may help you picture the 'localised' accumulation of certain fossils your finding and put things into context... its not easy to visualise the lay of the land from 300 million years ago and certainly with the geological changes and erosion that have took place it might be wrong to consider a level forested area your collecting from....Youve seen the cross section through the beds I photographed showing the fossil insitu tree stumps growing on the seat earth then now imagine walking across the top left hand side of this temporary exposure photographed below... Starting in the bottom right corner you are on the oldest (loweset) beds exposed and as you walk along the top edge of the hole towards the red digger on the top level... you can see the beds change quite quickly due to the angle of the mudstone layers... reasonably level when depositied but moved and lifted over many millenia by geological forces...and so will the fossils contained within the beds change also getting younger as you go along... that few hundred yards could represent a million years or so quite easily....

post-1630-0-45465600-1347269688_thumb.jpg

Cheers Steve... And Welcome if your a New Member... :)

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PS... I think this image may help you picture the 'localised' accumulation of certain fossils your finding and put things into context... its not easy to visualise the lay of the land from 300 million years ago and certainly with the geological changes and erosion that have took place it might be wrong to consider a level forested area your collecting from....Youve seen the cross section through the beds I photographed showing the fossil insitu tree stumps growing on the seat earth then now imagine walking across the top left hand side of this temporary exposure photographed below... Starting in the bottom right corner you are on the oldest (loweset) beds exposed and as you walk along the top edge of the hole towards the red digger on the top level... you can see the beds change quite quickly due to the angle of the mudstone layers... reasonably level when depositied but moved and lifted over many millenia by geological forces...and so will the fossils contained within the beds change also getting younger as you go along... that few hundred yards could represent a million years or so quite easily....

post-1630-0-45465600-1347269688_thumb.jpg

That's a really fascinating site! I'm kind of envious of colleagues who have access to coal mining operations where some of the best large-scale stuff is located. Tough to look at an entire tree when you're working with hammer and chisel, or exploring an abandoned quarry. I heard from someone recently that in the 1930s during the mining era, St. Clair produced a dragonfly with a 3 foot wingspan. In terms of the stratification and how the site may be contoured, at St. Clair, most of the orange and yellow leaf fossils are at the bottom part of the pit, and the white fossils are at the top. Since most sources say the leaves were pyrolized orange first, then "aluminized" to white, the white fossils should be older. Finding the orange fossils at the bottom and the white fossils at the top (of the slope, not the layers) is counterintuitive because you would assume the white fossils would be at the lower/bottom of the site, but the opposite is true.

You mention another consideration that I've been thinking about - it's easy to say that a Devonian or Carboniferous site may "only" cover 10 million years or so but even if it's a million, or a hundred thousand, that leaves a lot of room for extinctions and mutations and all kinds of minor variations - having said that, it's sort of amazing that there were so few variations in the fossil trees and leaves globally. My wife keeps commenting how incredible it is that the modern fern leaves at St. Clair - there are at least four or five different MODERN species and leaf patterns there - retain the morphology of the 307 mya ferns.

I'm falling into the group that believes that evolutionary changes occur rather quickly rather than gradually, driven by reasonably "sudden" external factors such as oxygen/CO2 levels, volcanoes blocking the sun for a few years, temperature/ice ages, and so on. Many of the creatures that are extinct now that we study in the fossil record did exist for tens or hundreds of millions of years, then either evolved kind of fast into something else to adapt, or went extinct altogether.

There are so many interesting things to think and wonder about, to analyze and discover, in this field...and they relate very much to what is happening today in what some people are calling the "6th extinction event."

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