Calamite

[blackmoth]

I guess this is calamite stem ( external imprint) fossil? Is it ture?

If yes I have some questions for experts here.

[paleoflor]

Calamites sp., indeed.

[blackmoth]

Thanks alot. BTW I guess I am wrong in saying it is a imprint. It is the out skin of the stem.

And here comes my first question. This one shown here has only the outser skin, no

pith. And the skin come together,some how like a book of skins with only thin

(1 mm or less range) clay inbetween the pages. And fossils like this are scattered everyhwere

in the site, ignored by the fossil hunters.

The leaves are also everywhere but the pitch is missing, which should form fossil more easily than other parts.

I could not conjure up a scenario for this to happen excpet that the plant would shed its stem skins.

But if it does shed the skin, one would imagine that the skin would break at the nodes and fall. However,

that does not seem to be the case.

Is it ever mentioned before by researchers?

Calamites sp., indeed.

[BobWill]

Often a calamites (the "s" is part of the name, not the plural form) fossil and even more commonly leaf fossils, are preserved by a process called carbonization. Also called compression, this process only leaves an extremely thin fossil best left attached to the matrix. Sometimes some pith is preserved beneath the bark but not always.

[paleoflor]

[...] It is the out skin of the stem. [...] This one shown here has only the outser skin, no pith. [...]

What do you mean exactly with the above? Your specimen shows clear ribbing, which is (save for in a few particular species of Calamites) generally not the case in a preservation of the epidermis (do you mean this with "outer skin"?). Fossils of the epidermis (a.k.a. Calamophyllites) typically have internodes with an otherwise smooth surface (perhaps lightly striated or wrinkled), leaving few diagnostic features. This is clearly not the outermost layer of the stem.

[...] This one shown here has only the outser skin, no pith. [...] The leaves are also everywhere but the pitch is missing, which should form fossil more easily than other parts. [...]

How do you use the word "pith" here? Calamites stems had a central cavity. Are you referring to (three-dimensional) casts of this cavity? Your specimens are rather typical, with the longitudinal ribs and nodes, and represent some internal part of the plant (i.e. not the outermost layer).

[...] Is it ever mentioned before by researchers?

There is plenty of literature on Calamites, explaining the general features and anatomy.

General palaeobotany, with a nice section on Calamites: Taylor et al. (2009) Paleobotany: the Biology and Evolution of Fossil Plants

Many descriptions and photographs: Kidston and Jongmans (1911-1913) A monograph of the Calamites of Western Europe

[blackmoth]

Thanks alot again. I guess my question is answered and I owe you and Bob a tuition.

I knew the calamites stem is hollowed, but thought that the xylem and phloem ( or what ever the stuff that prides the mechanical and nuitrition support) should

be of significant thickness ( even after fossilation) .

I was wrong. The seemingly razor thin fossil is the combination of compressed epiderms, phloem and xylem. Did I digest you and Bob's reply well?

What do you mean exactly with the above? Your specimen shows clear ribbing, which is (save for in a few particular species of Calamites) generally not the case in a preservation of the epidermis (do you mean this with "outer skin"?). Fossils of the epidermis (a.k.a. Calamophyllites) typically have internodes with an otherwise smooth surface (perhaps lightly striated or wrinkled), leaving few diagnostic features. This is clearly not the outermost layer of the stem.

How do you use the word "pith" here? Calamites stems had a central cavity. Are you referring to (three-dimensional) casts of this cavity? Your specimens are rather typical, with the longitudinal ribs and nodes, and represent some internal part of the plant (i.e. not the outermost layer).

There is plenty of literature on Calamites, explaining the general features and anatomy.

General palaeobotany, with a nice section on Calamites: Taylor et al. (2009) Paleobotany: the Biology and Evolution of Fossil Plants

Many descriptions and photographs: Kidston and Jongmans (1911-1913) A monograph of the Calamites of Western Europe

[BobWill]

Thank you, for the kind recognition but I owe my, often misremembered, factoids to the real experts like paleoflor who happily guide us along, tuition free, usually without recognition.

[Stocksdale]

Hi Paleoflor....

I'd like to ask a bit more help on the difference between Calamites and Calamophyllites if you don't mind. I understand that Calamites is the inner layer and Calamophyllites is the outer. The picture below you had in another post was very helpful.

I may be showing some my igorance on this. But, I've wondered about many of the Calamites from Mazon Creek. Many look like the inner part with the clear longitudinal ribs. But because of the quick fossilization at Mazon Creek, I'd think that there woud be mostly the outer part.

Also, when I look at a picture of a modern horsetail. Their outer layer to me resembles the typical Calamites with the clear ridges. The nodes also don't look that different from the inner Calamites nodes.

So, are there subtleties that I'm missing. How does one know if a Calamites is an 'inner' or an 'outer'.

Edited January 31, 2015 by Stocksdale

[paleoflor]

Good, very good questions. I'm not sure on this either, and probably unable to answer these questions to your satisfaction.

[...] I'd like to ask a bit more help on the difference between Calamites and Calamophyllites if you don't mind. [...]

Perhaps I overemphasized the term Calamophyllites. While it was specifically used in the past, for example by Grand'Eury (1869) and Zeiller (1888), for fossil specimens showing the smooth, outermost surface of calamitalean stems, Calamophyllites has since long been synonymized with Calamites Suckow, 1784 (Kidston and Jongmans 1917). I only included the term to relate back to older literature describing the outermost surface, so that people could find and compare with these references. However, I wouldn't recommend further usage of Calamophyllites. In the thread from which you took the image, I accordingly said that the specimen could be assigned to "Calamites, subgenus Calamitina", i.e. no longer using Calamophyllites.

[...] I may be showing some my igorance on this. But, I've wondered about many of the Calamites from Mazon Creek. Many look like the inner part with the clear longitudinal ribs. But because of the quick fossilization at Mazon Creek, I'd think that there would be mostly the outer part.

How would you define "outer part", I guess that is an important part of the question. I have included several images from the plates of Kidston and Jongmans (1915), which hopefully illustrate my thoughts better than my words will.

The above two images show details of Plates 1 and 2, depicting a particularly nice specimen of Calamites undulatus, which was described by Kidston and Jongmans (1917) as showing "the outer surface and pith cast in organic union". The left image clearly shows a smooth domain, referred to as the impression of the smooth bark, and a ribbed domain, referred to as the remains of the pith cast. As you can see the "smooth" portion of the stem shows vague outlining of the ribs, giving this outermost layer a very thin appearance. The right image shows a different position of the same specimen, where leaf scars can be seen on the smooth bit (i.e. far left) of the first internode from the top. Note that these structures are much less visible on the ribbed portion of the same internode. My impression from these images is that the distance (thickness of tissue?) between the "outer surface" and "pith cast" (in organic union) is very small.

I am not at all familiar with the Mazon Creek flora and her taphonomy, but would it take much to decay away that very thin surface prior to fossilization, even if it is quick? No idea...

On the other hand, as Plate 3, Fig. 2 and Plate 9, Figs. 1-2 (all Calamites undulatus) show, the distance between "outer surface" and "pith cast" could be somewhat thicker as well.

This is even more true for different species of Calamites, for example members of the Calamites schützei group. The following scan shows two specimens featured on Plate 79, both examples Calamites schützeiformis (forma waldenburgensis). For this species, the diagnosis states: "pith cast frequently bordered by a wide band representing the impression of the wood", which is probably referring to the coal-like material surrounding the ribbed structure in Plate 79, Figs. 3-4. Here the distance between the "outer surface" and "pith cast" is considerably larger.

Do the Calamites specimens from Mazon Creek would belong to species with this type of "wood"? I don't know, but I would guess not.

Okay, there are Calamites species that show some form of ribbing-like texture on the (near) outer surface, for example Calamites goeppertii, which shows clefts on the outer surface. In that sense your comparison with modern horsetails makes sense, perhaps.

[...] So, are there subtleties that I'm missing. How does one know if a Calamites is an 'inner' or an 'outer'. [...]

So what is the "outer part" (or the "pith cast", for that matter)? I am not completely sure. For me, it has been the smooth surfaces, as described in the older literature, while the "pith cast" was the ribbed material, at least, until I read DiMichele and Falcon-Lang (2012). These authors nicely show that both these definitions are rather uncertain. Perhaps reading their paper will help you answer your questions. Herewith their abstract:

"Sediment-cast calamitalean axes in growth position are one of the most common fossils in the Pennsylvanian coal measures. In this paper, we challenge the long accepted position that these fossils represent “pith casts”. If correct, the hypothesis would require the sediment-cast pith to have been surrounded by a cylinder of secondary xylem during life, which later decayed away. However, sedimentary layers and structures developed around upright calamitaleans indicate that fluid flow was interacting directly with the preserved surface of the stem, not a hypothetical woody cylinder that lay external to it. Furthermore, stem diameter–density data for calamitalean stands already lies at the self-thinning threshold, and if actual stem diameters were significantly greater than preserved diameters, this threshold would be significantly exceeded. We also note that measured diameters for upright sediment-cast calamitaleans are more similar to stem diameter data for anatomically preserved calamitalean axes than for pith diameter data from the same axes. Our findings indicate upright calamitaleans are in fact stem casts and their preservation involved a two-stage process. First, stems were buried in flood-deposited sediments, creating a mold of the external surface of the plant. Second, following near-total decay of the axis, which may have occurred in a matter of weeks under tropical conditions, further sedimentation infilled the mold, forming a cast. As such, the preservation of upright calamitaleans was identical to that for arborescent lycopsids, which are commonly found in the same beds. That said, we stress that some transported sediment-cast calamitalean axes preserved in fluvial channel facies are certainly “pith casts” in the traditional sense, however, their morphologies differ from those specimens traditionally called “pith casts”. In this context, axes were buried in a single phase of sedimentation under energetic flow conditions, resulting in the pith becoming sediment-filled. However, intriguingly, a review of such genuine pith casts shows that only a tiny proportion preserves large woody cylinders surrounding the pith. This is not a taphonomic feature, but reflects our contention that the great majority of floodplain-based calamitaleans were reed-like plants with relatively small amounts of secondary xylem. Woody calamitaleans, including large tree forms, are documented almost exclusively from petrifactions, and thus from peat-forming environments (coal balls) and, more rarely, floodplain settings under exceptional conditions of preservation (volcanigenic deposits, for example). These may be difficult to recognize in adpression preservation due to the masking, by wood development, of node-internode features. The differing architectures may reflect adaptations to disturbed and undisturbed environments, respectively." --- Abstract from DiMichele and Falcon-Lang (2012)

Particularly note "the great majority of floodplain-based calamitaleans were reed-like plants with relatively small amounts of secondary xylem", which relates back to the observations by Kidston and Jongmans, with the very thin layer of material between the smooth surface and the ribs.

Does this help at all? Hope that I at least didn't make it worse...

[Stocksdale]

Great info. Those images you post are very helpful in understanding the two layers.

I'll have to read through the paper that you posted. The PDF of it is a free download at the Smithsonian website.

Here's their link https://repository.si.edu/handle/10088/19375

Edited February 1, 2015 by Stocksdale

[Plantguy]

Awesome stuff guys...Wishing I was near a coal mine anywhere!

Tim, thanks for the detailed info.

Regards, Chris

[Stocksdale]

Interesting paper.

Am I understanding it correctly that they are saying that many of the fossils that were previously thought of as the pith may be impressions of the stem (including vascular bundles/xylem). Also it sounds like there is another layer (extraxylary tissues) that is not usually preserved. So there may be three different levels that could be preserved: pith, stem and extraxylary.

Here's an image from that paper that I added some color to the areas. Red is pith. Green is stem. Yellow is extraxylary.

[paleoflor]

Interesting paper.

Am I understanding it correctly that they are saying that many of the fossils that were previously thought of as the pith may be impressions of the stem (including vascular bundles/xylem). Also it sounds like there is another layer (extraxylary tissues) that is not usually preserved. So there may be three different levels that could be preserved: pith, stem and extraxylary.

Screen Shot 2015-02-01 at 1.46.38 PM.jpg

Here's an image from that paper that I added some color to the areas. Red is pith. Green is stem. Yellow is extraxylary.

This is more or less what I gathered from the paper also. True pith casts and casts of the entire stem (including vascular bundles/xylem, excluding extraxylary tissue) are ribbed, while conservations of the outermost layer (including extraxylary tissue) are relatively smooth. The most difficult part is distinguishing the former two.

[Stocksdale]

By the way, Blackmoth, welcome to the forum!!

And your example of calamites is very nice. And whether it is the inner or middle layer may remain something of a debate

Where did your example come from?

[Stocksdale]

Here's a calamites stem that I jut bought through eBay. It appears to show two layers. Is that the pith and stem, or stem and extraxylary? Or just a product of the preservation.

[paleoflor]

Calamites sp., indeed.

Given that the furrows between ribs seem to be bordered on each side by a prominent line (so-called "double furrows"), and that the ribs are tapered to a sub-acute point at the internode and alternate over consecutive nodes, you could try to compare your specimen with examples of Calamites cistii. Perhaps an identification to species level is possible for your specimen.

[blackmoth]

Thanks Stocksdale. It is picked at the same site as the (supposedly) Neuroptersi ovata I posted before.

It is a wellknown late carboniferious/early permian site for education purposes. Unfortunately I did not see

anybody during my two visits there,

. Otherwise I could have learned more about the place.

By the way, Blackmoth, welcome to the forum!!

And your example of calamites is very nice. And whether it is the inner or middle layer may remain something of a debate

Where did your example come from?

Edited February 2, 2015 by blackmoth

[Stocksdale]

Very nice. And exciting to see examples from such far off places (for me)!!

Edited February 3, 2015 by Stocksdale

[blackmoth]

my questions on these calamites are far from over. Based on the books and sources I could find so far, the followings are extablished knowledges:

1) in my pic the ribs go straight cross the nodes, this is a primitive feature prevalent in archae-calamites and common in meso-calamites, but rare in calamites. The latest time for meso-calamites is ealry carboniferious.

2) However, in the place where my calamites is found, the calamites is very common, and amost every piece has the ribs going across the nodes.

The site's age is later-carboniferious-early-permian. The whole north China is missing layers between later Ordovian to mid-carboniferious deposition.

3) another genus called para-calamites all have ribs going across the nodes. But they are not supposed to be found in north-China.

I could not find anybody here in Beijing to answer my question.

By the way, is the stuff in this pic a section of a small piece of calamites?

[blackmoth]

Given that the furrows between ribs seem to be bordered on each side by a prominent line (so-called "double furrows"), and that the ribs are tapered to a sub-acute point at the internode and alternate over consecutive nodes, you could try to compare your specimen with examples of Calamites cistii. Perhaps an identification to species level is possible for your specimen.

are you referring to my original pic? what part is the furrow (the yellow or blue)? and what is the rib?

Edited April 11, 2015 by blackmoth

[blackmoth]

this is another pice of calamites I picked on the same spot as the piece in my first post.

It seems to me this is a different species as the distance between the neibouring nodes is so small,

while the ribs are quite far between .

Aside from the above, it also looks very smooth, quite different from the 1st one. Does that mean it is of a different surface ( inner or outside)?

Edited April 11, 2015 by blackmoth

[paleoflor]

Definitely another species. Reminds me of a picture of Calamites steinhaueri. Need to look this up. Great specimen!

[paleoflor]

are you referring to my original pic? what part is the furrow (the yellow or blue)? and what is the rib?

I was, but I do not see any yellow or blue in your original photograph... The ribs are the bulging structures, the furrows are in between (not sure how to clarify this further).

[paleoflor]

my questions on these calamites are far from over. Based on the books and sources I could find so far, the followings are extablished knowledges:

1) in my pic the ribs go straight cross the nodes, this is a primitive feature prevalent in archae-calamites and common in meso-calamites, but rare in calamites. The latest time for meso-calamites is ealry carboniferious.

2) However, in the place where my calamites is found, the calamites is very common, and amost every piece has the ribs going across the nodes.

The site's age is later-carboniferious-early-permian. The whole north China is missing layers between later Ordovian to mid-carboniferious deposition.

3) another genus called para-calamites all have ribs going across the nodes. But they are not supposed to be found in north-China.

I could not find anybody here in Beijing to answer my question.

By the way, is the stuff in this pic a section of a small piece of calamites?

I've always found the distinction between Calamites and Asterocalamites a difficult one. If several ribs alternate, I assign the specimen to Calamites, even if there is also a significant number of ribs that appears to go straight through. Not sure how correct this is, though.

Looks like calamitalean foliage, yes.

Edited April 13, 2015 by paleoflor

[blackmoth]

Definitely another species. Reminds me of a picture of Calamites steinhaueri. Need to look this up. Great specimen!

people here said it is a typical Calamites suckowii. The big round leave bases on one side of the nodes line is not clear

in the pic ( because there is no color difference), but could be seen when you hold the piece in hand.