If not Silurian inarticulate brachiopod, what else could it be?

[SteveE]

Hi all, first post here.

 

Central PA,   Slab from roadside float from Mifflintown-Bloomsburg (undivided).   A thin layer contains a lot of small (1/16" dia), flattish fossils that I think might be inarticulate brachiopods.  I have a number of specimens from other parts of the exposed layers and these do not appear in any of the others.   One old paper on this formation mentioned "inarticulate brachiopods".   I'm new enough that I didn't know about the articulate and inarticulate division in this group, so I'm already learning stuff.  Awesome.    Googling some pics returned some images that kinda look like what I have.   But not quite.  What do you think?  If not inarticulate braichiopod, what else could they be?

 

 

 

 

[Tidgy's Dad]

Very nice.

Hello, and a very warm welcome to TFF from Morocco.

Ostracods, perhaps? 

[Al Tahan]

It’s doesnt appear to be an inarticulate brach here. I see there is almost a porous look in the center in one of your up close shots....maybe somthing like fish scale/plates? That’s a way far out guess. I can say for sure it’s not a brachiopod. 

[Pumpkinhead]

1 hour ago, Tidgy's Dad said:

Very nice.

Hello, and a very warm welcome to TFF from Morocco.

Ostracods, perhaps? 

 

+1 for ostracods

[SteveE]

Thanks for input, all.   Float from a much higher level in the formation did offer up some lassemblages of 1cm ostracods.  They're closer to spheres than flat like the little bitty things in this thread..... which I just noticed.... are adhered to the matrix with a material that flouresces yellow in UV.  Sorry about the blurry UV pic.... it takes three hands to hold the light, the Ipod and the hand lens I shoot through.

Edited March 23, 2019 by SteveE

[Fossildude19]

There was a post of very similar Ordovcian items from the Czech Republic that, unfortunately, never got resolved.   

 

 

 

Most inarticulate brachiopods have visible growth lines on them.   

 

[SteveE]

2 hours ago, Fossildude19 said:

There was a post of very similar Ordovcian items from the Czech Republic that, unfortunately, never got resolved. 

Most inarticulate brachiopods have visible growth lines on them.

 

Thanks for the link, that is a great mystery story and indeed sounds at least somewhat similar.    The slab has around 50 of these things.  None of them show any lines, neither radial nor concentric.  They all show some sort of opening in the outter layer, but the shape of these openings is pretty variable.   The variability makes me think the opening is not genetically determined, but a result of predation or environmental factors.   I'm really stretching my newbie knowledge but I gather from some scholary papers that the depositional environment was coastal marine with frequent transitions between terrestrial and submersed.  One of the ideas in the other thread was cysts or organisms that may have been exposed to drying conditions.   I'm just blathering here, but the variability in the openings could certainly be consistent with excessive shrinking during a dry spell.  I'll try to up my photo magnification game, shoot more pics, and do a more careful survey of the regional literature.  May be awhile but I'll try to followup here eventually.

[ondrej.zicha]

Hi, I've updated the original thread linked above with some new information.

 

Your fossils reminds me more of a problematic Silurian fossil Pachytheca, which is sometimes considered some stage of primitive moss or other early land plants or even fungi. However this genus probably works as a wastebin taxon for placing all kinds of small, featureless spherical fossils of unknown origin. Pachytheca occurs worldwide from Lower Silurian to Devonian. The determination can be confirmed only by studying a cross-section.

 

See for example here: https://steurh.home.xs4all.nl/engpach/epachy.html

[Auspex]

I am struck by the almost honeycomb-like under-structure:

This feature looks more organic than geologic to me, and may be a clue as to the specimens' identity.

[SteveE]

Well now this is embarrassing but I suppose I should fess up.....  These aren't fossils at all.   I still don't know what they are, but under magnification I tried to break one open and was rewarded with a gush of yellow goo.  Yikes!  They're alive!  Now I'm thinking some kind of arthopod egg or larva.   My apologies !!  My grade school aged daughter shares my hobby.  She says this is a "Foss-ilarm"

[ynot]

1 hour ago, SteveE said:

  She says this is a "Foss-ilarm"

[deutscheben]

Well I'll be! I collected some Pennsylvanian-aged fossils this weekend from an area with small brachiopods and gastropods and also found very similar grey scale-like "shells" on the same rock. After reading your post I went and poked them and they came off the rock revealing the same yellow substance. Yikes! Thank you so much for posting your update. 

[Auspex]

17 hours ago, SteveE said:

I tried to break one open and was rewarded with a gush of yellow goo

Thus was the Martian invasion thwarted...

"Foss-ilarm" should be a TFF meme!

[SteveE]

2 hours ago, Auspex said:

Thus was the Martian invasion thwarted...

 

I guess that makes it a family business!  My astrobiologist wife sometimes does planetary protection consults with NASA.  Only she gets PAID and I fight the aliens as a hobby......

 

PS Deutscheben,   glad I'm not the only one!  

 

[SteveE]

I'm still working on this.... at the moment, the leading contender is hunting spider egg-sacs.   It goes without saying that although I'm still working on an ID, my other half has evicted this particular project to the backyard.