What Species of Calamite is this?

[Rockin' Ric]

I am aware of the different species of Calmites but don't know all of them. Can anyone identify this one? I'm curious as to what the vertical seam separating the ribbing?

[Fossildude19]

Hey Ric! Another nice find!

 

I think you may have a Calamites approximatus, Schloth.

Have a look at #5  HERE

 

The description can be found HERE.

[Rockin' Ric]

Thanks Tim! I have found lots of Calmites but not many of these. This 3D stem was found last week at an active surface coal mine...I haven't posted the other finds yet? This helps in labeling these specimens for display. 

[paleoflor]

On 27/10/2017 at 1:48 AM, Rockin' Ric said:

This helps in labeling these specimens for display. 

Apologies in advance, for what follows below probably doesn't. Yet, I reckon it might be of interest.

 

As I had never heard of Calamites approximatus before, I went through some literature to learn about it. From what I can find, the species epithet appears to be in disuse and may no longer be valid. The species Calamites approximatus was erected by Von Schlotheim (1820, p. 399 = 230/251 of this PDF). Von Schlotheim did not figure any material, only mentioning six specimens coming from various localities in Germany. He did write that the species shows great resamblance to Calamites cannaeformis v. Schlotheim 1820, but with narrower ribs.

 

Von Schlotheim 1820, p. 399

Unfortunately, as is discussed at some length by Jongmans (1911, p. 60, 176-177 = 82/516, 198-199/516 of this PDF), both Calamites cannaeformis and Calamites approximatus are rather poorly described and characterized by Von Schlotheim.

 

Jongmans 1911, p. 60

 

Jongmans 1911, p. 176-177

 

Over the years, the vague descriptions of Von Schlotheim caused/allowed authors to assign specimens of quite different affinities to the two species. However, many of the specimens thus assigned to Calamites cannaeformis and Calamites approximatus were later considered to either belong to different species or to be too poorly preserved to be assigned to any species (see Jongmans 1911, 1915, Kidston and Jongmans, 1915-1917, Jongmans and Kukuk, 1913). The most complete review can probably be found in the monumental monograph on Calamites by Kidston and Jongmans (1915-1917). Unfortunately, this work is not freely available online (real pity, for this is an absolutely great reference). Luckily, however, during the preparations for the monograph, Jongmans published a "List of the species of Calamites with enumeration of the figures as far as they are doubtful or indeterminable or belong to other species", which can be found online. The specimen figured by Lesquereux 1879-1880, Plate 1, Fig. 5, is considered indeterminable (Jongmans 1915, p. 4 = 4/41 in this PDF).

[Scylla]

Excellent detective work! So what species is the above fossil?

[paleoflor]

18 hours ago, Scylla said:

So what species is the above fossil?

 

That's the main question, isn't it? Don't think I'd be able to answer it. My reasoning so far: The ribs clearly alternate at the nodes, which points to Calamites (rather than Asterocalamites, Protocalamites, Archaeocalamites, etc.). I cannot see any branch scars, roots scars, etc., which rules out species in the "subgenera" Cruciacalamites and Diplocalamites (often grouped together under Eucalamites in older works), as these should bear scars on (almost) every node. This leaves us with species grouped either in "subgenus" Stylocalamites (where branch scars rarely occur) or in "subgenus" Calamitina (where branch scars occur periodically, say on every x^th node). The specimen shows clearly constricted nodes, which helps us rule out most species of Stylocamites, such as the common C. cistii and C. suckowii, suggesting that we need to look at the latter "subgenus". Moreover, since the specimen shows four complete internodes/segments, only species from "subgenus" Calamitina with period x > 4 need to be considered (those with x < 4 can be ruled out, as we should have seen at least one node bearing branch scars). While this may sound great, it leaves us with a rather nasty situation, as many of the species in "subgenus" Calamitina have periods x > 4 and, moreover, these species are generally characterized by the diagnostic properties of the branch scars (placement, shape, periodicity, etc.). We thus need to consider how far we can get without using those properties... We can again exclude species with non-constricted nodes, such as C. undulatus and C. göppertii. Some other species can be excluded on the basis of size, rib termination shape and length-to-width ratio of the internodes. This has left me with C. schützei and part of "Weiss' C. varians group" used by Jongmans 1911 (note that this is outdated nomenclature). As the name suggests, the latter is a rather varied group... making it difficult to get to a more precise identification. Those interested could try to use Jongmans 1911 (PDF provided above) to get it sorted out further.

[doushantuo]

I like it that you unearthed the same documents i used to solve this problem

union chapel mine

[paleoflor]

On 27/10/2017 at 12:24 AM, Rockin' Ric said:

 I'm curious as to what the vertical seam separating the ribbing?

Could this be due to the stems splitting longitudinally prior to burrial and fossilization? The stems were hollow structures, which could perhaps split open upon flattening. I have seen similar structures in quite a range of different Calamites species, so I doubt it can be used as a diagnositic feature (also have not seen any literature sources where such a use is mentioned).

5 minutes ago, doushantuo said:

I like it that you unearthed the same documents i used to solve this problem

You solved this problem? I certainly didn't. How'd you ID the specimen?

[doushantuo]

My bad.I didn't "solve it",but tried to.

I'll let the gaffe stand,BTW,for the sake of clarity

Pith casts

More pith casts

[fiddlehead]

As these kind of problems go this is an easy one. In the Kinston & Jongmans, 1917 monograph (by for the most comprehensive on this subject) their Calamite schutzeiformis clearly conforms to what we have pictured here. They do not even describe Calamites approximatus as a separate species, it is only mentioned in the synonymy lists for C. schutzeiformis. As far as the Plate 1 Figure 6 in Lesquereux's 1879 figured plates, like Paleoflor mentions, they did not make a determination on it. But Kinston & Jongmans did agree that figure 16 in this plate from 1879 was C. schutzeiformis under Lesquereux's name Calamondendron sp. http://www.georgesbasement.com/LesquereuxAtlasP/Lesquereux-Plate75.htm Not that it matters, but Lesquereux agreed as much in his text, calling it likely a C. approximatus. What has also been missed is the fact, most, if not all of Schlotheim (1820) species names are now illegitimate according to International Code of Nomenclature ruling, do to vague descriptions and lack of any type specimens, i, e., Pecopteris arborescens Schlotheim 1820 is now changed to Pecopteris arborea. The short version is the name C. approximatus is now accommodated in the name C. schutzeiformis, and that is what you have. The odd vertical rib is found on many different species of Calamites and is a mystery to me, but it is not a diagnostic feature.  

 

Hope this makes things a little clearer.

Jack

[abyssunder]

What I've learned from this interesting topic is that the vertical rib (seam) is not a diagnostic for Calamites species, and it's good to know that. Good work everyone!

[Scylla]