Two Unknowns from the Upper Camb. Abrigo fm.

[Arizona Chris]

HI all,

 

Were going through our cambrian material from the Upper Cambrian Abrigo formation from southern Arizona, and besides hordes of trilobite bits, we have found two similar calcified items in the limestones which we are not certain of.  I think they are either plates from an eocrinoid, or sclerites from some sort of bottom dwelling crawly thing.  Now we do very occasionally find stem ossicles here, very rare in the upper cambrian, but dont know if they are crinoid or other stemmed pelmatozoan. Here is the photos I just took, let me know your thoughts!

 

 

[Miocene_Mason]

Remind me of sand dollar pieces I find at the cliffs, but I’m sure The was a least I little bit of evolution between the Cambrian and the Miocene.

[ynot]

They look like crinoid or eocrinoid to Me, But I am not that well versed in cambrian fauna.

[MeargleSchmeargl]

I haven't a clue, honestly.

 

 

@piranha ...?

[Tidgy's Dad]

A cystoid plate. 

It actually loos like a Rhombiferan like Pirocystella

Or especially Echinoencrinites 

But these are Ordovician. 

 

[Miocene_Mason]

@Tidgy's Dad a little early for a cystoid, don’t you think?

[Tidgy's Dad]

1 minute ago, WhodamanHD said:

@Tidgy's Dad a little early for a cystoid, don’t you think?

Indeed, that's what i said, "But those are Ordovician", so yes, if Arizona Chris' specimen is for certain Upper Cambrian, it can't be them 

 

I was wondering if there were maybe Ordovician sediments there too 

[Miocene_Mason]

35 minutes ago, Tidgy's Dad said:

But those are Ordovician"

Missed that.

[Arizona Chris]

The do look just like cystoid plates.  I have never found such a thing before.  The Abrigio is almost totally undocumented as far as fauna.  Perhaps an :Eocystoid" if such existed.  There are some eocrinoids found in this formation, but no one has ever seen their calyx.  Maybe this is one?  Also we had Golgia.  Finding close up of thier plates is not easy...

[Tidgy's Dad]

Hmmmm.

You mean Gogia? 

This one's from the Burgess Shale. There are similarities, I think, but not the same and I thought they didn't survive the Middle Cambrian.   

[Arizona Chris]

Here is another clue I found JUST last night, a very unusual stem piece that for all the world looks like it belongs to the same animal.  Very much resembles the rhombiferan stem pic above!

 

[ynot]

3 minutes ago, Arizona Chris said:

Here is another clue I found JUST last night, a very unusual stem piece that for all the world looks like it belongs to the same animal.  Very much resembles the rhombiferan stem pic above!

I do not see what You are referring to. Can You point it out please?

[Arizona Chris]

Ok, the photo is a bit flat looking, a consequence of the stacking program.  This is a side view of a filled stem section.  You can see the exterior ribs and the center is filled with a sausage of sediment that sticks out on both ends of the central canal.

[abyssunder]

Figure 2. A, the hemicosmitoid Oocystis showing well developed radial ridges; B, the hemicosmitoid Corylocrinus showing pustular
ornamentation; C, the coronate,Mespilocystites; D, a fragmentary specimen of the diploporitan cf. Codiacystis; E, the diploporitan cf.
Tholocystis; F, the eocrinoid Bockia; G, the caryocystitoid Heliocrinites; H, the echinosphaeritid Echinosphaerites showing well
developed heumatorhombs; I, a single thecal plate of the glyptocystitoid rhombiferan Rhombifera.

All figures are whitened latex casts
of natural molds.

[ynot]

@abyssunder

Any information to go with the picture?

[piranha]

1 hour ago, ynot said:

Any information to go with the picture?

 

 

Sumrall, C.D. Deline, B., Colmenar, J., Sheffield, S.L., & Zamora, S. (2015)

New data on Late Ordovician echinoderms from Sardinia, Italy.

In: Zamora, S., & Rábano, I. (eds.)  Progress in Echinoderm Palaeobiology.

Cuadernos del Museo Geominero, 19:175-180   PDF LINK

[Arizona Chris]

Those are some nice crinoid plates, but none remotely resemble the pattern I have.  Im still leaning toward a cystoid type.  But you have suggested to me I would be benefited by also considering the patterns of some early crinoids.  Thank you for your suggestion. I will next spend some time in the Treatise and index fossils on echinoderms!

 

 

[abyssunder]

13 hours ago, ynot said:

Any information to go with the picture?

C. D. Sumrall et al . 2015. New data on Late Ordovician echinoderms from Sardinia, Italy. Progress in Echinoderm Palaeobiology: Cuadernos del museo Geominero, Volume 19:175-180

[abyssunder]

representative Cambrian echinoderms

 

excerpts from S. Zamora et al. 2013. Cambrian echinoderm diversity and palaeobiogeography. Geological Society London Memoirs 38:157-171

[Arizona Chris]

These are fantastic animals!  Not even science fiction has imagined such a wild diversity.  Still digging into the references, and Ill be doing an update when we find more material.  (were still photogaphing the Abrigo fossils)