My submission for the world's smallest trilobite contest and more stuff from Arkona 12/4/2017

[Greg.Wood]

It was only 9 days since my previous (and first) trip to HH, but I was itching to go back and decided to take advantage of the mild weather this Monday. I spent most of the day on the north side of the south pit picking tiny fossils out of the mud. There are an astonishing variety of critters to find if you don't mind lying face down in the dirt.

 

1. Tiny trilobites!

I was not expecting to find any trilobites until I spotted the guy on the left. Luckily I had a small ziplock bag or I would have lost these for sure. They are about 2.5 and 3.0 mm across the head.

 

2. Nautiloids

Fragments like these are most common after brachiopod and crinoid bits

 

3. Ammonites/goniatites

Also very common but one of my favorites, I will never find enough of these.

 

4. Brachiopods and bivalves

Fragments everywhere but a bit harder to find complete

 

5. Another brach

Nothing special, just nicely inflated and good detail on both sides

 

6. Another brach

A little more interesting. I only found one like this.

 

7. Gastropod

I found many fragments that suggest this shape but this one is by far the most compete.

 

8. Crinoid stem fragments

Very abundant but these ones caught my eye

 

9. Part of a crinoid calyx? (opposite sides of the same piece shown)

 

10. Cystoid plates

Could be wrong, I just learned about cystoids so I'm bound to imagine seeing them everywhere

[Kane]

Well done! When I was there a day earlier, the Arkona mud was "blooming," so many of the lovely little bits were obscured.  The Goniatites are always a delight to find, and you certainly hoovered up a good number of them! I find that the trilobites in the Arkona Fm tend to be fairly small. I think your #10 are crinoid holdfasts. Looks like you had a fantastic trip! 

[LiamL]

I like those tiny Ammonites the most.

[Shamalama]

24 minutes ago, Greg.Wood said:

It was only 9 days since my previous (and first) trip to HH, but I was itching to go back and decided to take advantage of the mild weather this Monday. I spent most of the day on the north side of the south pit picking tiny fossils out of the mud. There are an astonishing variety of critters to find if you don't mind lying face down in the dirt.

 

1. Tiny trilobites!

I was not expecting to find any trilobites until I spotted the guy on the left. Luckily I had a small ziplock bag or I would have lost these for sure. They are about 2.5 and 3.0 mm across the head.

 

2. Nautiloids

Fragments like these are most common after brachiopod and crinoid bits

 

3. Ammonites/goniatites

Also very common but one of my favorites, I will never find enough of these.

 

4. Brachiopods and bivalves

Fragments everywhere but a bit harder to find complete

 

5. Another brach

Nothing special, just nicely inflated and good detail on both sides

 

6. Another brach

A little more interesting. I only found one like this.

 

7. Gastropod

I found many fragments that suggest this shape but this one is by far the most compete.

 

8. Crinoid stem fragments

Very abundant but these ones caught my eye

 

9. Part of a crinoid calyx? (opposite sides of the same piece shown)

 

10. Cystoid plates

Could be wrong, I just learned about cystoids so I'm bound to imagine seeing them everywhere

#4 are all bivalves (Pelecypods) with the bottom row being Paracyclas sp., next up is Nuculites triqueter., and the top row I am unfamiliar with. I'm surprised you didn't find any comma shaped specimens of Phestia which crawling around.

#5 is probably a Rhipidomella sp. brachiopod

#6 is a Cyrtina sp. brachiopod

#7 I'm not sure of but that is a beauty to come out of the Arkona Fm.

#9 is the base of a crinoid caylx, possibly Arthrocanta sp.

#10 are Crinoid plates from a calyx. Frustratingly common.

16 minutes ago, LiamL said:

I like those tiny Ammonites the most.

The fossils in pic #3 are not Ammonites, they are Gonaitites. Ammonites don't appear until the Mesozoic.

[Kane]

4 minutes ago, Shamalama said:

 

#10 are Crinoid plates from a calyx. Frustratingly common.

The fossils in pic #3 are not Ammonites, they are Gonaitites. Ammonites don't appear until the Mesozoic.

Thanks, Dave. I got into the bad habit of just calling those holdfasts for some reason, but you're right that they are plates. Derp!

 

And, yes, the Goniatites are not ammonites, but subclass Ammonoidea 

[Tidgy's Dad]

A splendid assortment of beautiful tiny creatures! 

[Ludwigia]

Nice little haul! The great thing about these tiny ones is that you don't have to strain yourself to get them back to the car and also that they don't take up all that much space once you get them home 

[DoyouthinkhesaurusRex]

Very cool! Nice haul, indeed

[Miocene_Mason]

Love the trilos and the Gontiatites! 

[Bobby Rico]

Fantastic I never thought trilobites can be so small . Beautiful collection. Thank you

[Jeffrey P]

That's an amazing haul of beautiful pyrite preserved specimens there. The goniatites, nautiloids, bivalves, and the gastropod are my favorites. Congratulations and thanks for posting.

[Archie]

Awesome finds! Love the goniates!

[Fossil-Hound]

Very nice little trilobites.

[oldtimer]

Very nice haul.  I like the Brach in #5.  It's what we find around my area.  Very nice specimen.  I also like the crinoid parts in 8 and 9. Thanks for sharing.

[Greg.Wood]

22 hours ago, Shamalama said:

#4 are all bivalves (Pelecypods) with the bottom row being Paracyclas sp., next up is Nuculites triqueter., and the top row I am unfamiliar with. I'm surprised you didn't find any comma shaped specimens of Phestia which crawling around.

I may have mistaken the comma shape for broken fragments at a glance, I'll have to pick some up next time. What do you think of the small one in the bottom row? It has longitudinal ridges rather than lateral like the first 4. Not much detail in this picture so it may be hard to tell.

[Shamalama]

1 hour ago, Greg.Wood said:

I may have mistaken the comma shape for broken fragments at a glance, I'll have to pick some up next time. What do you think of the small one in the bottom row? It has longitudinal ridges rather than lateral like the first 4. Not much detail in this picture so it may be hard to tell.

Oops.... missed that little guy. He looks like a brach but it's hard to tell. can you get a pic of him alone and maybe a little closer? Opposite side as well if possible.

[Greg.Wood]

3 hours ago, Shamalama said:

Oops.... missed that little guy. He looks like a brach but it's hard to tell. can you get a pic of him alone and maybe a little closer? Opposite side as well if possible.

Did some messing around with the microscope. Need to figure out the lighting a bit better but it worked pretty well:

[Shamalama]

Thanks @Greg.Wood Ok, that is a tiny oddball you have there. Let's walk through some ID basics. 

 

It's hard to tell without seeing it in person but the fossil appears to be symmetrical. It also appears that one valve pokes our a little father from the hinge line than the other. 

 

It's also a black color, likely the result of shell replacement with phosphatic material or possibly Pyrite which is oxidized to Goethite on the surface, which is common for mollusk fossils in the Arkona formation. 

 

I see thick ribs that extend from the back hinge line to the margin of the shell and in a couple of the pictures you can see evidence for annual growth rings.

 

I do not see a sulcus structure which is often found in many brachiopods and is a matching groove/ridge structure typically centered on the shell.

 

At this point I am leaning towards a Pelecypod but what type is stumping me at the moment. Let me consult some literature and in the meantime let me know if any of my conjecture is incorrect.

 

[crinus]

I believe that #6 is a brachiopod, aka Cyrtina.

 

Just noticed that someone else caught that also.

[Max-fossils]

Very cool finds!

 

I like the bivalves in #4. I love the brachiopod in #6 too, what a wicked shape!

 

And that little bivalve in the last pictures is absolutely stunning. Love how well it is preserved and that black color. For ID, reminds me of Cardita sp or Venericardia sp shells. Then again those species were likely not there at that time. So the initial thought was from the Carditidae family, but then (seeing that one of your tags is Devonian, I take into account that all the fossils you found are indeed Devonian) I realized the age wasn't right. Maybe look in the Carditoida order. I know that it's a broad spectrum but maybe it helps. 

 

Let me know what you find ID-wise 

 

Thanks for sharing by the way!

 

Max

[Nimravis]

I will give you a run for the smallest trilobite, meet Aphelaspis brachyphasis from the Cambrian Conasauga Formation of Georgia.

 

[Monica]

Beautiful finds, @Greg.Wood!!!  I really like the detail on your crinoid stem (#8) - the zigzag suture pattern is so clear!!!  Congratulations on finding all of your cute little critters!

 

Monica