Ordovician sponge?

[Paciphacops]

I just pulled this out of a box of old fossils, but I'm not exactly sure where I originally found it. I think it is from the Carter's limestone, middle Ordovician, in the Nashville, TN  area. It has a similar shape and size (~2 cm dia) to Hindia, but I have not seen anything else with this distinctive pattern of parallel criss-crossing ridges. Any ideas?

 

Thanks 

 

[Al Dente]

It reminds me of Ischadites, a type of algae.

[Tidgy's Dad]

I think it's Receptaculites sp. a probable chlorophyte algae. 

[Miocene_Mason]

8 minutes ago, Tidgy's Dad said:

I think it's Receptaculites sp. a probable chlorophyte algae. 

Fisherites if Ordovician, receptaculites is restricted to the Devonian I think (that’s what @piranha said I while ago I think, can you confirm?)

[Tidgy's Dad]

You may be right. I would have been safer saying a receptaculitid, I think. 

Yes, here's the link. 

 

[Tidgy's Dad]

And another paper, which mentions several species and other genera.

https://www.app.pan.pl/archive/published/app38/app38-233.pdf

[fifbrindacier]

I also think it's an algae, to compare with, see my goniolina hexagona from the Kimmeridgian of France (it is in a gasteropod shell) :

[Paciphacops]

The patterns do look similar to Receptaculites or Fisherites, but not sure about the shape, which appears to be spherical, with a flat side. I'm not entirely sure it is Ordovician, my second guess is Devonian Ross Formation. 

[Tidgy's Dad]

If you are uncertain of the provenance, either location or age it could be any of the above genera. Better just list it as a receptaculitid. 

[fifbrindacier]

Maybe someone who know the brachiopods could recognize them and so help us to narrow the edge of that piece.

I also don't think it's a receptaculites, i'm sure it is another algae.

Here are other pics of Goniolinae :

 

This honey-like pattern is'nt rare in the flora or fauna word, see also those pics of paleodictyon, traces of a very old animal that still exists :

Fossils :

 

Moderns :

[Paciphacops]

I think I found it! It appears to be Solenoides sp., from the Birdsong Shale member of the Ross formation and apparently very rare. It is shown in "Lower Devonian Fossils of West Tennessee" by Kieran Davis. 

 

http://www.memphisgeology.org/images/Devonian Fossils of West Tennessee.pdf

 

I need to keep digging through more of my old fossils!

 

[fifbrindacier]

31 minutes ago, Hal said:

I need to keep digging through more of my old fossils!

 

So, a very rare sponge , and a so well preserved one, incredible !

You surely should digging through more of your old fossils (maybe you'll have another little sponge for me ?).

[Tidgy's Dad]

2 hours ago, Hal said:

I think I found it! It appears to be Solenoides sp., from the Birdsong Shale member of the Ross formation and apparently very rare. It is shown in "Lower Devonian Fossils of West Tennessee" by Kieran Davis. 

 

http://www.memphisgeology.org/images/Devonian Fossils of West Tennessee.pdf

 

I need to keep digging through more of my old fossils!

 

You could be right. 

Nice find.

And a nice find! 

[piranha]

The Kieran Davis publication misspelled the genus, it should be 'Selenoides'

 

Nitecki, M.H., & Rietschel, S. (1985)

Redescription of the holotype of Selenoides iowensis Owen, 1852.

Journal of Paleontology, 59(3):568-571

 

ABSTRACT-  Selenoides Owen, 1852, previously considered to be a junior subjective synonym of Ischadites Murchison, 1839, is a receptaculitid genus endemic to North America, and includes many undescribed species. The holotype of the type species S. iowensis, Owen, 1852, is redescribed, and the genus Selenoides is re-established as valid.

 

 

The classification of receptaculitids is still unresolved Problematica.

 

text from:

 

Nitecki, M.H., Mutvei, H., & Nitecki, D.V. (1999)

Receptaculitids: a phylogenetic debate on a problematic fossil taxon.

Springer Scientific Publishing, 241 pp.

 

We know that we have succeeded only in showing that receptaculitids were neither sponges, archaeocyathids, nor dasyclads, because the cumulative receptaculitid characters are not those of sponges or of algae. It is surely premature to ask what they were-we must still wait to know that. We are far from providing final answers, but we hope that others will be stimulated to ask new questions, and to accept receptaculitids as more than the sum of their characters. The preponderant lesson from our morphological analyses has shown us that complete understanding of the nature of the receptaculitids is not yet possible; therefore, in order to build a strong case on the nature of receptaculitids we either had to endlessly speculate, or admit our ignorance. The German idioms and expressions have changed since Rauff wrote (1892a:648), and the current rendition of his conclusions as shown in our Dedication (p. v) may now be rephrased. We now believe that we do not know enough to be definitive, and have been left no choice but to follow Rauff in retaining receptaculitids in the Problematica.

 

(Translation of Rauff 1892a:648)

"My investigation on the true nature of receptaculitids has had the painful result of again evicting these interesting fossils from their taxonomic position, and setting them adrift once more. Perhaps my observations on their most extraordinary structures will help some luckier, more informed person discover their true affinities. It is this hope which has caused me to publish this work even without its most important conclusion; at least it may serve as a basis for further analysis. Receptaculitids are again removed from their taxonomic position, without resolving their systematics, and it is hoped that the present paper will form the bases for future phylogenetic analyses." 

[abyssunder]

excerpts from R. V. Kesling & A. Graham. 1962. Ischadites is a dasycladacean alga. Journal of Paleontology 36(5): 943-952

 

[Paciphacops]

After going over my trips to Birdsong sites, I remembered exactly where I found this fossil. It was an exposure along a rural highway in southwest Wayne County, TN, 20 years ago. Definitely from the brachiopod zone. 

 

I'm calling it Selenoides sp. It is also pyritized, so it will be interesting to see how it cleans up.

 

Thanks for all the information.