Tiny Carboniferous Steps (Joggins, Nova Scotia)

[Oxytropidoceras]

Tiny Carboniferous Steps by Brian Switek

Wired News, September 6, 2012

http://www.wired.com...niferous-steps/

the paper is:

Stimson, M., S. G. Lucas, and G. Melanson, 2012,

The Smallest Known Tetrapod Footprints:

Batrachichnus salamandroides from the

Carboniferous of Joggins, Nova Scotia, Canada,

Ichnos: An International Journal for Plant and

Animal Traces, vol. 19, no. 3, pp. 127-140.

http://www.tandfonli...940.2012.685206

http://www.tandfonli...=gich20#preview

Best wishes,

Paul H.

[grokfish]

Very cool!

[trilobiteruss]

Wow those are small but nice!

[Auspex]

It would have been the size of a largish insect!

[AgrilusHunter]

Neat!

[Auspex]

Seriously! Look at the scale:

[AgrilusHunter]

There are extant plethodontids of comparable size. Link

[Ailsa]

Aww they are tiny I wish I could find something as amazing as that!

[mstimson29]

It's all about luck and knowing what your looking at when you find it Ailsa.

-Matt

Aww they are tiny I wish I could find something as amazing as that!

[mstimson29]

There are extant plethodontids of comparable size. Link

Indeed but your plethodontids have elongate torso. The manus (front) and Pes (back) feet pairs in the trackway indicate a much shorter torso.

[Auspex]

Indeed but your plethodontids have elongate torso. The manus (front) and Pes (back) feet pairs in the trackway indicate a much shorter torso.

Matt,

I can't say how pleased we are that you would respond to this thread, and share some of your insights!

[cvi huang]

http://www.scienceda...20911125108.htm

EDIT: Merged for continuity

Thank You! sorry Now I know for 'news' topics are here, and i was only repeat thing, in future first i will read after write

Edited September 13, 2012 by cvi huang

[AgrilusHunter]

Indeed but your plethodontids have elongate torso. The manus (front) and Pes (back) feet pairs in the trackway indicate a much shorter torso.

Hi Matt,

Good point. It is a pleasure to hear from the first author on the referenced work. I really enjoyed reading your manuscript and look forward to seeing more of your posts. Welcome to the forum!

[mstimson29]

Hi Matt,

Good point. It is a pleasure to hear from the first author on the referenced work. I really enjoyed reading your manuscript and look forward to seeing more of your posts. Welcome to the forum!

Hi AgrilusHunter, Auspex and all. I suppose the username is not so incogneto huh? Thank you for the warm welcome! The honor is mine seeing you folks posting and discussing our paper! I am very glad you enjoyed the manuscript! Its was a lot of fun to write.

Matt

[Fossildude19]

Hi AgrilusHunter, Auspex and all. I suppose the username is not so incogneto huh? Thank you for the warm welcome! The honor is mine seeing you folks posting and discussing our paper! I am very glad you enjoyed the manuscript! Its was a lot of fun to write.

Matt

Hello Mr. Stimson,

I was wondering if you would be willing to tell us more about this find, and maybe some behind the scenes info about your involvement with the writing of the papers?

I'm sure many of us here would enjoy hearing more about this if you are willing to share.

Regards,

Edited September 18, 2012 by Fossildude19

[pleecan]

It is wonderful to have famous people visit this humble forum. Congratulations to Matt and your research team on this wonderful find!

[mstimson29]

Haha famous? I am not sure I would go that far lol But thank you for the kind words.

Sure, I would be happy to elaborate more on the project. Any specific questions?

M

[Fossildude19]

Matt,

Thanks for taking the time to answer some questions. I appreciate that.

Congratulations on the paper - I found it an interesting read - thanks for that, as well.

Okay, I do have a few questions for you, as I am interested in the methodology used in the of writing the paper.

Hope this isn't too elementary, or inane.

1.) Was the specimen found loose as float, or quarried? Was the counterpart ever found? What is the most common method of finding the ichno fossils at this famous locality? - Is it mostly loose float finds, or quarried material, or a mixture of both?

2.) How many other ichnofossil specimens were compared to this find to try to arrive at a likely culprit for the trackmaker?

3.) How long did it take to compile your data, and write the paper?

4.) What were the closest sized ichno fossils that were compared, and what were the differences in size?

5.) In the article cited, it states you think that a juvenile Dendrerpeton is the most likely candidate for the trackmaker.

It's clear from the paper that you are leaning towards a juvenile, regardless of species, as the trackmaker, but you also stated there were some other possible candidates. I understand we will never know for sure, however, what are your thoughts about this?

Can you get a little more in depth as to what you feel made the tracks, and why?

Again, I'm just genuinely interested in what goes on behind the scenes. I appreciate any comments you are willing to make on the subject.

Thanks again.

Regards,

[mstimson29]

Hi Tim,

Good questions, all. well I will answer them in order. my apologies for any grammar or spelling errors its rather late and I just arrived back in Halifax late tonight. So my latin spelling may not be ready for any spelling B;s tonight.

1.) Was the specimen found loose as float, or quarried? Was the counterpart ever found? What is the most common method of finding the ichnofossils at this famous locality? - Is it mostly loose float finds, or quarried material, or a mixture of both?

A) the specimen was found loose in float near the base of the cliff in a recent rock fall by my close friend and coauthor Gloria Melanson. When she picked up the fossil a paper thin layer of the counterpart shattered and collapsed to the beach. It was unrecoverable. The Joggins cliffs are on average 100ft tall and lay along the Bay of Fundy. The crashing tides and ice build up in the winter, liberate new fossil material daily. So, nature does the quarrying for us. It is very rare that a fossil is excavated from the cliffs.

2.) How many other ichnofossil specimens were compared to this find to try to arrive at a likely culprit for the trackmaker?

A) Many! Don Reid (the "keeper of the cliffs" and Gloria's father) and Gloria have looked at likely hundreds of specimens from the Joggins site over the years. A research team Including my coauthor and I among many other colleagues documented the entire trackway collection at Joggins in the past and these were by far the smallest yet seen at the site. The assignment to the ichnogenus Batrachichnus was easy. There are only so many ichnogenera it can fall under in the Carboniferous. Dr. Lucas and I searched all of the available literature on carboniferous trackways and realized the description of the prints fits the trackway we are looking at . The slipper fit. We also noticed that the ichnogenus Batrachichnus seemed to be the smallest in the literature at present. This ichnotaxon has been extensively studied by many other scientists who have amalgamated most of the other small trackway varieties into this single ichnospecies based on the fact they were morphological variations of the same trackways. An extensive review of the literature showed that Gloria's find was the runt of the litter. My good friend and colleague at Joggins has nicknamed them the worlds smallest and cutest fossil footprints.

The hardest part on the taxonomy assignment was distinguishing between Batrachichnus and Limnopus. Both are 2 of the most common trackways at Joggins, Most of the Batrachichnus specimens at Joggins are in the 5 mm range. Limnopus can range to multiple centemetres. Morphologically they are nearly identical minus the size. Previous authors have debated that they should be synonimized. The distinction is the smaller ones fall under B. salamandroides, Larger ones fall under Limnopus. As our specimen was small already, and Batrachichnus has priority if the 2 genera are later merged, our classification would be preserved based on the law of priority and was the best fit.

3.) How long did it take to compile your data, and write the paper?

Longer than it was supposed to haha. We originally planned to write up a short paper with very few conclusions except that these were the smallest trackways at Joggins, later in the world. With each new answer new questions emerged. I wanted to know how large the animal was that left the traces and who might the culpit have been. Why were the trackways preserved and what was the strange change in the footprints along the course of the trackway. As we went farther down the rabbit hole with each new question the paper got longer and longer and took more time. It took about a year to compile the data, write the paper, submit for peer review, wait for reviews, debate with the reviewers and finally see the end product in print.

4.) What were the closest sized ichno fossils that were compared, and what were the differences in size?

The closest to our trackway was one actually from Joggins described by Frederick Matthew around the turn of the `19th century. They measured roughly 5 mm each. some traces were recorded by Dr. Voigt as having 3 mm front feet but the back were much larger. Gloria;s specimen is at least half the size and smaller than most comparable traces. The most relevant data is provided in the table in the paper.

5.) In the article cited, it states you think that a juvenile Dendrerpeton is the most likely candidate for the trackmaker.

It's clear from the paper that you are leaning towards a juvenile, regardless of species, as the trackmaker, but you also stated there were some other possible candidates. I understand we will never know for sure, however, what are your thoughts about this?

Can you get a little more in depth as to what you feel made the tracks, and why?

Good question. There are 2 sides to this answer. Firstly, we name trackways different from the animal that made them. this is important as many salamander like creatures can leave the same trace fossil if they have similar feet . OR depending on the behavior, sediment type, water saturation in the sediment, one animal can leave many types of footprints along a single path. SO, looking only at the trackways and ignoring the animal that left them for a moment, we previously thought that the larger (5mm scale) Batrachichnus specimens were juvenile of the larger Limnopus trackways. We now know there was something smaller. Some larger Batrachichnus are still likely juvenile forms of the larger Limnopus footprints. HOWEVER, equivalent sized (larger) Batrachichnus are likely also adult forms of the smaller Batrachichnus . Distinguishing the "medium" sized traces which fall into the middle ground between our fossil and the larger Limnopus traces is likely impossible. However being as this specimen is so diminutive, it would appear to be unmistakably a juvenile.

Part 2 of this answer is what made the footprints.

Joggins is a very unique place for study the carboniferous world. We not only have the trackways of primitive reptiles and amphibians, but also the bones. AND rather than the large skeletons which are normally preserved elsewhere in the world, the hollowed out fossil tree stumps entomb the smaller animals inside the trees. So we have a very good bone record to sort through.

We reviewed all of the literature on the skeletons at Joggins and did some detective work. If we look at the the broad groups that lived in Joggins ( that we know of) we have a the reptiles ( represented by Hyonomus lyelli (anapsid) and protoclepssydrops (synapsid)). Reptiles have 5 , long and stringy toes in a pattern we call lacertoid. The slipper does not fit as the front feet of this animal has 4 short and stubby toes like an amphibian. The anthracosaurs ( reptile like animals) also fall into this with 5 toes and are thus excluded from the lineup. The amphibians are left. they are broken into 2 major groups, the Temnospondyls and and the Microsaurs. Batrachichnus and its larger cousin Limnopus are among the most common trackways at Joggins. The Temnospondyls are by far ( mainly Dendrerpeton) are the most common animal preserved in the trees. A coincidence? I think not! Previous work world wide has attributed Batrachichnus and LImnopus to temnospondyls based on their 4 blunt toes in the front and 5 longer toes in the back ( among other features). The microsaurs also have a very similar foot shape and could easily wear the same pair of shoes. The microsaurs are preserved as fragmentary remains but we did have an articulated 3d skeleton of a Dendrerpeton. Where as the body forms are not all that different in both groups, we decided to use the articulated skeleton as a model to calculate the size of the animal.

Was it made by a Dendrerpeton? Maybe, it could have easily been one of its cousins. But regardless the model should fit.

After looking at the bones we realized we have no bones that match the size of the trackways. A little fellow called Sparodus ( likely a juvenile Leiocephalikon) came close but its bones were still the size of the entire calculated torso of the animal. Where are the bones? Either they are so small we have simply not found them, they became dinner and we should be looking in coprolites, OR the juvenile grew up and lived a long happy life and we find them fossilized as adults. ( my preference)

Hope this helps Happy to answer any further questions.

Long answers, sorry.

Matt

[AgrilusHunter]

What a fabulous thread. Certainly one of the best I've read on the forum since I've been a member. Thank you.

Edited September 20, 2012 by AgrilusHunter

[Auspex]

This is absolutely fascinating! Thank you so much for taking the time to 'pull back the curtain' and lend us some insights into both these ancient creatures, and the art of interpreting them. Well done all around!

[Fossildude19]

Matt,

Thanks so much for answering my questions.

I really appreciate that. I enjoyed your answers,and did not mind the length of them in the least - no need to apologize.

I found your replies fascinating.

Thank you, once again. And please keep us informed of whatever you are working on with these or other fossils from Joggins.

I for one would be interested in anything new you have to add.

Regards,

[mstimson29]

http://www.cbc.ca/quirks/

for anyone interested.

M

[AgrilusHunter]

And you said you weren't famous. Great job all around, I really enjoyed listening to the interview.

Edited September 24, 2012 by AgrilusHunter

[mstimson29]

http://www.cbc.ca/quirks/

for anyone who is interested. We were interviewed on CBC Radio Quirks and Quarks.

M