Adam's Cambrian

[Huntonia]

This looks identical to a bug I prepped that I labelled as an E. kingii meraspid, I'm fairly confident that's what you're looking at but I could be wrong. It's a beauty in any case!

[Tidgy's Dad]

7 hours ago, Huntonia said:

This looks identical to a bug I prepped that I labelled as an E. kingii meraspid, I'm fairly confident that's what you're looking at but I could be wrong. It's a beauty in any case!

Lovely specimen. 

I think that you are quite likely right, Debra, who sent me this piece, also mentioned that. 

How big is that bug? 

And I absolutely agree that both yours and mine are beautiful whatever they may be! 

Edited June 7, 2021 by Tidgy's Dad

[Huntonia]

2 hours ago, Tidgy's Dad said:

How big is that bug? 

And I absolutely agree that both yours and mine are beautiful whatever they may be! 

Mine's 0.9cm long

[Tidgy's Dad]

5 hours ago, Huntonia said:

Mine's 0.9cm long

Thanks. 

Yes, more or less the same size as mine, then. 

[Tidgy's Dad]

I was hopeful at first that this specimen was something unusual, maybe an Altiocculus harrisi, but once I'd tidied it up a bit, it seems to me that it has the wrong number of segments in the thorax and the cranidium is wrong. I think it's actually just an Elrathia kingii with the sides of the pleurae broken off making in look long and thin. 

Never mind. Better luck next time. 

Positive and negative : 

An eye or two : 

 

Edited June 20, 2021 by Tidgy's Dad

[Tidgy's Dad]

This Wheeler Shale stuff is quite interesting to look at. 

Look at this piece. 

Packed full of Wheeler Wierdies. 

You can see a smattering of the cyanobacterium Morania fragmenta, and of course larger trilobits which are probably the ubiquitous Elrathia kingii : 

Sometimes they drive my Spidey-Pareidolia-Sense  crazy and I have to force myself to stay focused :

 

[Tidgy's Dad]

Then there are huge quantities of bits which I think are all agnostids, or pieces of agnostid. 

1 to 3 mm.

[Tidgy's Dad]

Blobby cyanobacteria or algae?

More cynaobacteria / algae and a sort of spine? 

These ones seem to be cyanobacteria radiating out in rings from a central point :

 

[Tidgy's Dad]

Bit of priapulid worm? 

[Tidgy's Dad]

In one or two of the specimens above you can see long spiky things. Here is a good example of another (scale in mm :

Could this be a sponge spike? I know that the Protomonaxonid sponges of the Choiidae family had long spines formed from specialized spicules that were thought to be defensive, but more recently I have read that the sponge body may have been balanced on these like stilts to keep it above the sea bed and thus away from predators with someone suggesting water currents were channeled up the spines to openings in the sponge for feeding purposes.     

 

Another spiky thing :

[Tidgy's Dad]

Finally in the same piece, there are a couple of these pieces that look quite like Margaretia dorus in some respects, but are rather small. 

This first one is under a centimetre long and the openings are far smaller than I would expect. 

A very young one, perhaps? 

And an even smaller fragment of something :

 

[Tidgy's Dad]

I'm going for 'sponge' with this one. 

I think it was disintegrating during preservation so has left bits or spicules in the matrix surrounding it as it decomposed.

9 mm long for the main body.

Edited June 26, 2021 by Tidgy's Dad

[Tidgy's Dad]

Another couple of 'worms'  / burrows / other trace fossils? 

Were these two linked somehow or two different creatures sharing the same environment? 

Or just mineralogical? 

 

Edited July 2, 2021 by Tidgy's Dad

[Tidgy's Dad]

All sorts of interesting looking bits in this piece. The rock is 2.6 cm long from tip to tip. 

Where a trilobite exoskeleton has broken away and left a mold? 

 

Bit of cranidium? 

And an agnostid bit?

One of these looks rather like a free cheek / genal spine.

No idea what these are............

 

 

Edited July 2, 2021 by Tidgy's Dad

[Tidgy's Dad]

I rather like this bit. 

I don't think it's just a bit of slickenside or something geological.

I'm thinking sponge spikes from one of the protomonaxonids such as Choia or Lenica. 

Photos from web for comparison :

Image from Relationships of the Cambrian Protomonaxida by Botting et al. 

Images 2 and 3 are Choia, though these are from the Hetang biota.

Edited July 2, 2021 by Tidgy's Dad

[Tidgy's Dad]

Surely this has to be something interesting?

Bit of an arthropod appendage? 

Some of it still seems to have shiny black exoskeleton attached, or is that just mineralogical? 

[Tidgy's Dad]

I do so love these tiny trilobits.  This one's about 2 mm long. 

But this little rock also has some interesting objects on the other side. 

Worms? Burrows? I dunno.

 

[Tidgy's Dad]

This is one of my favourites. 

It is the pale mineral staining near the bottom left of the rock to which I am referring.

The rest of this side of the rock doesn't seem to contain anything else identifiable though the reverse of the piece, which is 1.8 cm thick, has a large but poorly preserved trilobite, probably Elrathia kingii. It's 1.7 cm long. 

 

Also on the reverse to the stain are a couple of small bits of what I suspect to be agnostids; here's an example or two, the one centre left is about 0.5 mm :

The stain itself doesn't look very interesting, no detail of anything to speak of :

So what caused it?

Debra boshed the rock to split it open and find out 

The piece on the bottom right shows what was immediately under the pale stain 

The piece on the left is the positive of the other.

It would appear that some creature has died and during decomposition or fossilization has created the stain. Similar stains occur in many specimens from the Mazon Creek for example, as well as in the British Chalk, where sponges leave similar orange stains and impressions.

Detailed examination of the negative would appear to show some structure and possible pores in places. The 'goblet' shape and the size are suggestive of the sponge Crumillospongia, but my specimen would appear to have something a lot like a stem visible to the bottom left. If it is a stalk, and not just a bit of disintegrating body, then I don't think it could be Crumillospongia that type of sponge has more of a slightly pointed base rather than a stem.

 

Detail :

Here is the positive piece :

It does seem to be a stalk. I still think sponge, but echinoderm could be possible? 

The main body has broken free on the underlying matrix, so here we see the negative to the right, the main body positive top left and the other side of the stain bottom left. The actual specimen has been squashed and is only 3 mm thick  :

The reverse side :

Fascinating. I love this stuff. 

 

 

[Tidgy's Dad]

This one has already had a thread showing specimens found in the Wheeler Shale by Debra. 

Honeycomb pattern patches - New Photos - Fossil ID - The Fossil Forum

She has kindly sent this positive and negative to me. Each of the actual fossil fragments is 1.7 mm at the longest / widest.

One side, I just can't really get good photos of at all.

The other side is a bit better :

The photos above and below are about the best and do seem to show radiating curves of pits.

Here are Debra's original photos :

So, I've just had a bit of a play about, given the specimen a gentle rub and tried photographing it under slightly different light levels and angles. here are the best of the new batch :

 The specimen appears to show raised lumps or tubercles. 

And after another bit of toothbrushing it appears to be possibly pentagonal or more likely hexagonal if complete with a kind of hub in the centre : 

 

 

 

 

 

 

 

[Tidgy's Dad]

Several pieces of my Wheeler Shale matrix show lines of blobs that sometimes bifurcate. Maybe Yuknessia simplex? 

This was thought to be a green algae for about a century but then LoDuca et al. showed evidence that it's actually an early pterobranch and thus related to graptolites. 

Another rock : 

And a third piece :

And from another piece of shale :

Same rock, but something different :

Another piece of Wheeler :

 

[Tidgy's Dad]

Like Yuknessia simplex, Magaretia dorus was long considered to be a seaweed / green algae, but is now considered to be the housing tube for the 'Acorn Worm' Oesia disjuncta, though this is still debated. This would make Margaretia also an early hemichordate but from the other Class; the Enteropneusta. 

They seem to show in the Wheeler Formation as wide, dark 'sticks' and it seems only some of them still have the oval 'stem' openings preserved as in this specimen from the collection of Debra : 

 

Lovely.

Many of the possible M. dorus seem to be just internal molds and don't exhibit the openings clearly if at all.

Here are the specimens of possible M. dorus that Debra sent in my latest wonderful package.

The one top left :

Top right specimen and the right hand side of it : 

The central section is broken off ; 

The left hand of the specimen : 

The bottom left specimen from the original photo :

This thing on the same rock is interesting. Organic or mineralogical? 

 

The specimen from the bottom centre of the original photo :

And other oddments from this rock :

 

And the final piece of shale, bottom right in the original photograph.

That's it for the Cambrian for now. 

Thanks so much for all these fantastic specimens, Debra @Paleome Love 'em all. 

I've really had fun with these but it's a return to the Ordovician for me for now....................

 

 

 

[piranha]

On 7/7/2021 at 7:52 AM, Tidgy's Dad said:

Like Yuknessia simplex, Magaretia dorus was long considered to be a seaweed / green algae, but is now considered to be the housing tube for the 'Acorn Worm' Oesia disjuncta, though this is still debated. This would make Margaretia also an early hemichordate but from the other Class; the Enteropneusta.

 

Very interesting....as a result Margaretia is now a junior synonym of Oesia disjuncta.

Somehow I managed to miss this significant news....thanks for posting it Old Bean!

 

Nanglu, K., Caron, J.B., Morris, S.C., Cameron, C.B. 2016

Cambrian Suspension-Feeding Tubicolous Hemichordates.

BMC Biology, 14(56):1-9  PDF LINK

[Tidgy's Dad]

5 hours ago, piranha said:

 

Very interesting....as a result Margaretia is now a junior synonym of Oesia disjuncta.

Somehow I managed to miss this significant news....thanks for posting it Old Bean!

 

Nanglu, K., Caron, J.B., Morris, S.C., Cameron, C.B. 2016

Cambrian Suspension-Feeding Tubicolous Hemichordates.

BMC Biology, 14(56):1-9  PDF LINK

Indeed. 

There are not a lot of algae left in the Wheeler, they're pretty much all now cyanobacteria or hemichordates, it seems. 

Most delighted to have been of use for once, my fine fellow.  

[Tidgy's Dad]

A couple of fossils from China, now, sent to me from Spain by @Paleorunner, due to the kindness of @Kane as the latter won an auction lot offered by the former and only wanted the trilobites on offer so arranged for the other three fossils to be sent to me!  

Thanks, guys. 

These two are from the Chengjiang Biota, Yuanshan Formation of Jining District, Kunming Prefecture, Yunnan Province, China. 

First is the early lingulid Diandongia pista, my earliest brachiopod at about 520 million years old.

The actual brachiopod is 1.5 cm wide.

 

 

 

Edited September 28, 2021 by Tidgy's Dad

[Tidgy's Dad]

The second one is the (possible) priapulid worm Cricocosmia jinningensis. The genus has its own family, the Cricocosmiidae which, along with several similar families of Early Cambrian worms, are included in an order which is sometimes referred to as the Cricocosmida but more often as Palaeoscolecida incertae sedis. The Palaeoscolecida are a class of 'worms' included in the clade Scalidophora and are considered a stem group to this clade and maybe early priapulids or a stem group to this phylum. It gets a bit confusing as the class Archaeopriapulida could also be stem Scalidophora and certainly seem ancestral to be stem group priapulids. 

Anyway, I think it's wonderful even though the anterior end (head) is missing.

  

These are not body segments in the same way the unrelated annelids are segmented, but sclerite rings, seemingly a sort of body armour. 

 

This would seem to be the posterior end, showing a short area with an 'unsegmented' look and possessing two hooks which were presumably used to anchor the animal into its burrow if something tried to pull it out!  There is also visible a slightly darker stripe running along the length of the body which is the animal's gut. I love soft tissue preservation !  

Central section : 

The anterior end is missing :

Thanks again to @Kane and @Paleorunner for these two extraordinarily fascinating specimens! 

 

 

 

Edited September 30, 2021 by Tidgy's Dad