Several Fern Seeds From St. Clair - Incl. Attached Aleth. Seed

[hitekmastr]

On our recent half day trip to the St. Clair fern pits (Aug 11), we focused mostly on finding fossil fern seeds. All of these seed fossils came from one half-day visit. The isolated fossils were found on pieces of shale we inspected from the many piles strewn around the excavated collecting pits. Those that show both halves came from fragmenting small to medium sized pieces from the cast-off pieces around the pits. This was a time-consuming exercise in patience and involved a certain amount of luck but as you can see, we accomplished our goal which was to collect some well-articulated seed fossils.

Most of these are Alethopteris seeds including the best find (1a/1b) that shows both halves of the seed and the seed stem. We're wondering about the "split top" seeds - are these Alethopteris seeds starting to open up, or something else?

At least two of these (Seeds 4 and 5) are shapes we can't find in the fossil reference literature.

1a and 1b. Alethopteris seed attached by stem. Our best find was this trigonocarpus (fern seed) showing the stem attached to an Alethopteris sprig. We haven't seen too many seed fossils this well defined including the seed stem and associated fern leaves all attached to the same stem. Update: "Trigonocarpus" is the general name given to fern seeds. Our seed is attached by a short stem to the mid-rib of an Alethopteris fern pinnule. We do not believe this is a coincidence (for example the seed lying on top of a leaf) because it is perpendicular to the frond stem and the attachment is pretty clear on both halves of the fossil. We were fortunate to collect both halves and this specimen is very well articulated. (Nancy actually discovered this by splitting open a fragment that was cast aside at one of the small pits dug by other fossil hunters - we have found a lot of our most exciting and rare fossils by segmenting pieces that are already lying on the ground around this site - of course, there are thousands of fragments so it takes a keen eye, it helps to know how the different structures relate to each other so if there is a cluster of a certain species you know what to look for and where, and always it helps to have some luck. We have emailed our photos to the paleontologists at UC-Berkeley who have an artist's rendition of this seed/attachment on their site (see my post below). They mention on their site that not many attached alethopteris seeds have been found. More photos of this are included in my post below.

Unidentified Seed 1a and 1b. This is an isolated fern seed not associated with a specific type of fern leaf. Both halves are shown. It has a distinctive groove in the top.

Seed 2. Another isolated fern seed.

Seed 3. Another similar fern seed.

Seed 4 is a different shape - a round seed with serrated edge.

Seed 5 is another different shape that we see frequently although it's usually not very well articulated. Is this a seed or something else? It's always this shape.

Seed 6a and 6b are both halves of the same seed and have the same shape (groove at the top) as Seed 1a/1b above.

Seed 7 is another isolated seed.

Thanks in advance for your opinions!

Edited September 1, 2012 by hitekmastr

[hitekmastr]

I have an old topic with seeds from St. Clair. Just put your cursor over the picture. The file name has an ID name of the seeds if that helps.

http://www.thefossil...-fossil-plants/

Terrific post! Very helpful. Great seeds and wings - a strong incentive to keep exploring...really like the story about fragmenting the piece after you got home to find the wing.

[Fossildude19]

I could be totally wrong here, but #4 looks more like a calamites in cross section possibly at the nodes.

Great finds!

Thanks for posting them.

I find myself routing for you to find that ellusive insect or amphibian.

Continued success to you.

Regards,

Edited August 14, 2012 by Fossildude19

[Herb]

Very nice!

[hitekmastr]

I could be totally wrong here, but #4 looks more like a calamites in cross section possibly at the nodes.

Great finds!

Thanks for posting them.

I find myself routing for you to find that ellusive insect of amphibian.

Continued success to you.

Regards,

I think you're right on about the calamites stem - that's really funny considering how many crinoid stems and disks we've seen - it should have been obvious. We're still processing the finds from our first 3 trips, using a closeup camera lens and magnifying glass - we find a lot when we're back home and everything is spread out on a tabletop. Right now we're thinking about what our next target might be when we get back the end of the month or early Sept. Considering your advice about insects and other creatures, trying to come up with a strategy that will increase the odds.

[Terry Dactyll]

Hi...Very nice finds.... I'm pretty sure the seed (1a/1b) and Alethopteris are not attached... If you look closely at appears attached by a leaf identical to the one above it and I cant see a seperate stem...Its an association piece where the fern and seed have been fossilised together... The Trigonocarpus types are difined by changes in size and also subtle shape differences which could also be the same seed at different stages of development in many cases...The seeds with a grove at the top I would say are Cordaitanthus lindleyi.... and the rounded one (seed 5) looks like Samaropsis gutbieri...Maybe one of the other carb plant collectors can double check...

[hitekmastr]

Hi...Very nice finds.... I'm pretty sure the seed (1a/1b) and Alethopteris are not attached... If you look closely at appears attached by a leaf identical to the one above it and I cant see a seperate stem...Its an association piece where the fern and seed have been fossilised together... The Trigonocarpus types are difined by changes in size and also subtle shape differences which could also be the same seed at different stages of development in many cases...The seeds with a groove at the top I would say are Cordaitanthus lindleyi.... and the rounded one (seed 5) looks like Samaropsis gutbieri...Maybe one of the other carb plant collectors can double check...

This is VERY helpful - have to agree that the Alethopteris seed looks like it's overlaying one of the leaves instead of attached by a stem-- the "stem" lines up perfectly to be one of the leaves on the sprig, but also lines up perfectly with the seed so it could be a separate seed that is so closely associated it looks like a stem. I looked closer at the sample and tried to find some veins on the "stem/leaf" but the specimen is not articulated enough.

The several Trigonocarpus/alethopteris showing seeds in different stages is very cool.

I had been wondering if the grooved seeds were Cordaianthus/Cardiocarpus or alethopteris seeds opening up but - if they are true grooved seeds they add something new to our species from St. Clair.

The round seed looks like Samaropsis from other images on the Web - we'll keep an eye out for a better articulated fossil on a future trip to help confirm.

Thanks for your opinions!

[hitekmastr]

Hi...Very nice finds.... I'm pretty sure the seed (1a/1b) and Alethopteris are not attached... If you look closely at appears attached by a leaf identical to the one above it and I cant see a seperate stem...Its an association piece where the fern and seed have been fossilised together... The Trigonocarpus types are difined by changes in size and also subtle shape differences which could also be the same seed at different stages of development in many cases...The seeds with a grove at the top I would say are Cordaitanthus lindleyi.... and the rounded one (seed 5) looks like Samaropsis gutbieri...Maybe one of the other carb plant collectors can double check...

The UC Berkeley plant fossil pages show an illustration that shows the same orientation of the seed to an Alethopteris stem and notes that few examples of this attachment have been found. We believe this seed is attached as the Berkeley illustration shows - and as the Berkeley caption states, this is still being debated since these seed attachments are very rare. We believe ours is another bit of evidence to suggest that this is how the seeds were attached.

This illustration is from Berkeley's website - http://www.ucmp.berk...yc/MedCyc2.html Caption:Pachytesta (Trigonocarpus) ovule attached to Alethopteris foliage. The connection and orientation of the ovule is interpretive as few examples of ovules in physical connection with foliage have been found to date.

Edited September 1, 2012 by hitekmastr

[Trevor]

Awesome finds, but dont know much about seeds.

[Auspex]

The UC Berkeley plant fossil pages show an illustration that shows the same orientation of the seed to an Alethopteris stem and notes that few examples of this attachment have been found. We believe this seed is attached as the Berkeley illustration shows - and as the Berkeley caption states, this is still being debated since these seed attachments are very rare. We believe ours is another bit of evidence to suggest that this is how the seeds were attached.

Good research; you present a compelling case!

[gobbler716]

I recently found one near the Cahaba River in Alabama, seed pod and all.