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ID Request: Texas Lower Cretaceous Invertebrate

JustRain1176

By JustRain1176
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JustRain1176 Newbie

JustRain1176

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Hello Fossil Forum!

This is my first post and I kindly thank anyone who reads it for their time and attention.

I recently collected several specimens from sites in the Pecos River valley in Val Verde County, Texas (29.59.57 N, 101.29.00 W). If correct, my initial research seems to indicate that these strata are of lower Cretaceous age and belong to the Comanche series (Fredericksburg / Washita). I have done some internet research but so far I have not been able to find other examples which closely match what I have observed / collected.

I would really like to properly label my specimens, so any help is sincerely appreciated! All specimens were collected from the same location with the shell and nerinea found at the same elevation.

The first specimen I have labeled "coral" because that is what it looks like to me. I have provided two angles of this specimen. The second specimen I have labeled "nerinea" because this is the closes match I have found. The third specimen I have simply labeled "shell" and have provided two angles.

I also have numerous photos of what I believe to be some species of rudist and, I believe, another species of nerinea in-situ which I can post later.

Again, sincere thanks for your time and attention!

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post-20467-0-22283100-1452543784_thumb.jpg

post-20467-0-91047000-1452543784_thumb.jpg

post-20467-0-42739700-1452543785_thumb.jpg

post-20467-0-02166100-1452543786_thumb.jpg

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Auspex Regular Member

Auspex

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Rudists?

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>May your wonders never cease!

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Ptychodus04 Regular Member

Ptychodus04

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Larger photos would be helpful. The specimen in photos 1 & 2 appears to be a rudist. Photo 3 is a gastropod (Possibly Turitella sp.). Photos 4&5 could represent a broken gastropod.

Regards,

Kris

 

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JustRain1176 Newbie

JustRain1176

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Hello everyone,

Kind thanks for your effort! Please see attached higher resolution photo of the "coral", as requested.

post-20467-0-89088400-1452548700_thumb.jpg

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JohnJ Regular Member

JohnJ

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Larger photos would be helpful. The specimen in photos 1 & 2 appears to be a rudist. Photo 3 is a gastropod (Possibly Turitella sp.). Photos 4&5 could represent a broken gastropod.

Agreed. Not a coral. Rudist in 1 & 2, gastropod in 3, and broken gastropod in 4 & 5. Your higher res image is a rudist.

Your location is on the edge of two geologic maps. However, I think your finds originate from the Segovia Formation in the Edwards Group. Rudists and gastropods can be common in certain strata. If you are among the rudists in that layer, keep an eye out for Goniopygus sp. echinoids. Sometimes the tiny spines will be scattered in the rudist reef.

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The human mind has the ability to believe anything is true.  -  JJ

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JohnJ Regular Member

JohnJ

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Higher resolution photo of suspect nerinea.

This is more likely a Turritella species.

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The human mind has the ability to believe anything is true.  -  JJ

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JustRain1176 Newbie

JustRain1176

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It's rough country with old / incomplete survey data but I agree it looks like the Segovia Formation.

Turritella for the second specimen also looks right. But, can anyone advise the exact species?

I would also very much like to know which rudist you all suggest specimen #1 is? There are so many species and all of the examples of Texas rudists I have seen do not look quite like my sample.

Thanks so much for your help JohnJ and everyone else!

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abyssunder Regular Member

abyssunder

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For #8 I'm leaning toward Nerinea aquilina. post-17588-0-20643200-1452553417_thumb.jpg

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

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JohnJ Regular Member

JohnJ

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It's rough country with old / incomplete survey data but I agree it looks like the Segovia Formation.

Turritella for the second specimen also looks right. But, can anyone advise the exact species?

I would also very much like to know which rudist you all suggest specimen #1 is? There are so many species and all of the examples of Texas rudists I have seen do not look quite like my sample.

Thanks so much for your help JohnJ and everyone else!

Nailing down the species would be tough on the Turritella. An 'undomesticated' lead on the rudist could be Eoradiolites davidsoni.

The human mind has the ability to believe anything is true.  -  JJ

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JustRain1176 Newbie

JustRain1176

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JohnJ,

Am I off-base in thinking that the attached is Eoradiolites davidsoni? Which seems bigger and ridged when compared to my "coral" sample?

Kind thanks!

post-20467-0-26641300-1452554822_thumb.jpg

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Herb Regular Member

Herb

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I tend to agree with JohnJ

"Absence of evidence is not evidence of absence"_ Carl Sagen

No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go.

" I think, therefore I collect fossils." _ Me

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Twinlukers Regular Member

Twinlukers

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I've been in that area and I believe they are gastropods. Nice finds.

I'm heading back to Enchated Rock in a couple of weeks and stopping at a couple of sites on the way back.

More pictures??

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JohnJ Regular Member

JohnJ

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JohnJ,

Am I off-base in thinking that the attached is Eoradiolites davidsoni? Which seems bigger and ridged when compared to my "coral" sample?

Kind thanks!

I'm definitely not a rudist specialist. ;) You might contact Ann Molineux (bottom right of the page); she is a rudist expert. ;)

The human mind has the ability to believe anything is true.  -  JJ

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abyssunder Regular Member

abyssunder

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Only a longitudinal median section through the gastropod might reveal the difference between Nerinea and Turritella. I could be wrong, but for me the specimens from the following comparative pictures looks close to the specimen in question (#8).

post-17588-0-13359700-1452601719_thumb.jpg limestone with shells of gastropods Nerinea sp., Upper Jurassic, Crimea - http://paleostratmuseum.ru/coll%20389.html

post-17588-0-75950600-1452601805_thumb.jpg http://www.thefossilforum.com/index.php?/topic/31683-some-sort-of-spiral-shell/

post-17588-0-27850200-1452601788_thumb.jpg http://www.steinkern.de/steinkern-de-galerie/sonstige-fundorte-oberjura/Nerinea%20tuberculosa%20%28Roemer%29.html

post-17588-0-69503200-1452601774_thumb.jpg

Edited by abyssunder

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

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JohnJ Regular Member

JohnJ

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For #8 I'm leaning toward Nerinea aquilina. attachicon.gifNerinea.jpg

Nerinea aquilina occurs much lower in Texas Albian strata (Glen Rose Fm.). This find was likely from the middle Albian, Segovia Formation (unless it was found away from the rudists in the caprock). It could be a species of Nerinea or Cerithium.

(I sometimes 'over-generalize' the Texas tall spired Cretaceous gastrods as "turritellas"... :blush: )

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The human mind has the ability to believe anything is true.  -  JJ

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abyssunder Regular Member

abyssunder

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You could be right,Sir. Thank you for the information. :)

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

Thomas Mann

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RyanNREMTP Regular Member

RyanNREMTP

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I agree with JohnJ on the rudist ID. Another possibility is Eoradiolites robustus. But I can't tell for certain.

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abyssunder Regular Member

abyssunder

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My suggestion is, try to eliminate from the possible Eoradiolites candidates, looking at the transverse section of them, then other characteristics. For example:

Cross-section circular; form cylindrical; no ribs; E and S smooth, elevated bands - E. choffati.
Cross-section oval or triangular oval
Usual (medium) length for genus; interband I between E and S costate - E. liratus.
Test extremely long, slender; interband smooth - E. davidsoni.
Cross-section triangular-rounded; species small, a rapidly expanding, low cone - E. triangularis, E. rousseli.
Cross-section quadrate
Practically no ribs on posterior, dorsal and anterior faces; siphonal bands low, interbands shallow - E. plicatus.
Ribbed on all faces; siphonal bands tall; interbands deep
Form thick; section taller than wide 6 anterior costae - E. quadratus.
Form slender; section wider than tall; 1 anterior costa - E. angustus.

E = anterior siphonal band
S = posterior siphonal band
I =interband
V = pedal fold
L = ligamentary ridge

post-17588-0-38717700-1452988956_thumb.jpg

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" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

Thomas Mann

My Library

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