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aeljalaf

Eagle Ford Shark Teeth

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aeljalaf

Hey, I found a few shark teeth in the Eagle Ford fm in a construction site in the town of Denton, just north of Dalla.

Can someone help me identify what shark species they are ?

Also, there were these large shells that appeared rotated, and they were extremely common in the area. Any idea on what those are as well?

Thanks

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JohnJ

The oyster is a Texigryphea sp.; the shark teeth might be a Squalicorax and Cretolamna. Those that know sharks better can ID these Upper Cretaceous teeth.

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Guguita2104

Congratulations!The first bivalve seem a Texigryphea Mucronata...About the tooth, I agree with JonhJ.

Edited by Guguita2104

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aeljalaf

Wonderful thanks !

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Uncle Siphuncle

The IDs look good, but the stratigraphy seems out of place, based on fauna and location. I'm guessing you are in the Grayson Formation if you are very close to Denton, which is all Lower Cretaceous. The Kef outcrops well to the east.

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aeljalaf

The IDs look good, but the stratigraphy seems out of place, based on fauna and location. I'm guessing you are in the Grayson Formation if you are very close to Denton, which is all Lower Cretaceous. The Kef outcrops well to the east.

You are correct, My bad bad.

Here is the exact location I found them. (in the parking lot behind the Albertson store).

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TNCollector

The tooth on the left is a pseudocorax sp., not a squalicorax. They are very similar, with the former normally being a bit rarer.

The tooth on the right is a cretalamna sp.

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Al Dente

Pseudocorax teeth have a nutrient groove. I'm not seeing one on this tooth.

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Foshunter

Nice finds, Squalicorax curvatus and Cretolamna appendiculata-----Tom

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abyssunder

I agree with JohnJ and Guguita about the oyster.Texigryphaea mucronata (Gabb,1869) looks a good ID. Trying to give a reference I found this paper : The type species of Mortoniceras and the holotype specimens of Lower Cretaceous Texigryphaea of the southwestern United States - Robert O. Fay http://www.ogs.ou.edu/pubsscanned/NOTES/GN-V35N2.pdf
page 50, figure 7-8.

Nice find,BTW!

Edited by abyssunder

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JohnJ

I agree with JohnJ and Guguita about the oyster.Texigryphaea mucronata (Gabb,1869) looks a good ID. Trying to give a reference I found this paper : The type species of Mortoniceras and the holotype specimens of Lower Cretaceous Texigryphaea of the southwestern United States - Robert O. Fay http://www.ogs.ou.edu/pubsscanned/NOTES/GN-V35N2.pdf

page 50, figure 7-8.

Nice find,BTW!

Thanks for the great reference, 'abyssunder'. ;)

Given it was found in the Upper Cretaceous Grayson formation, I think this oyster is likely Texigryphaea roemeri. The older species T. mucronata is found in abundance in lower stratas.

Texas Cretaceous Bivalves, Akers & Akers

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abyssunder

I think you are right,JohnJ! post-17588-0-65417100-1436654841_thumb.jpgpost-17588-0-54911800-1436654869_thumb.jpgpost-17588-0-35437200-1436661411_thumb.jpgpost-17588-0-95539300-1436700915_thumb.jpg

But i don`t understand something: in the Robert O. Fay`s document I cited, Texigryphaea roemeri (Marcou,1862) figures 9&10 is the same as Gryphaea mucronata Gabb, figures 1-3,Plate XXVI of document The Lower Cretaceous Gryphaeas of the Texan region - Robert Thomas Hill,Thomas Wayland Vaughan https://books.google.ro/books?id=oqkPAAAAIAAJ&pg=PA38&lpg=PA38&dq=illustrations+of+texas+cretaceous+texigryphaea+species&source=bl&ots=KRC5ANYjSX&sig=xeX4guDekKD7nvAzWxNXkpfZUKE&hl=en&sa=X&ei=tZ-hVYK5POL5ywPmpKCAAg&redir_esc=y#v=onepage&q=illustrations%20of%20texas%20cretaceous%20texigryphaea%20species&f=false, in wich the figures are copies of Roemer`s original figures of what he called Gryphaea pitcheri.

Also in United States Geological Survey Professional Paper 211- Studies of some Comanche Pelecypods and Gastropods - T.W.Stanton https://books.google.ro/books?id=t0tXAAAAMAAJ&pg=RA1-PA29&lpg=RA1-PA29&dq=texigryphaea+graysonana&source=bl&ots=l8wIUqE1H5&sig=zTWIvpQxg1RXD3L3sbIbSuvzWFA&hl=en&sa=X&ei=liiiVfirNo-p7Ab7n6b4Bg&redir_esc=y#v=onepage&q=texigryphaea%20graysonana&f=false, plate 18, figures 1-26 are shown Gryphaea mucronata Gabb (the fourth picture in post #12).Looking at the pl. 11_fig.2,5-11/pl.12_fig.1-7/pl.14_fig.5,12,14-16 I`m wondering if is not possible that the specimen in question to be Gryphaea graysonana Stanton, n.sp. ?

post-17588-0-44370800-1436700965_thumb.jpgpost-17588-0-33698700-1436700975_thumb.jpgpost-17588-0-35018900-1436700985_thumb.jpg

Edited by abyssunder

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DPS Ammonite

I have always been confused (and the references seen to be contradictory) about the ID of and the number of species of Texigryphea that occur in the Lower Cretaceous Grayson Formation in north Texas. I usually use "A Field Guide To Fossils of Texas" by Charles E. Finsley. According to photos 179 and 180 in Finsley, the Texigryphea from Denton looks like T. mucronata which he describes as a synonym of T. marcoui. He also says that T. graysonana (and the synonym T. roemeri ) also occur in the Grayson Fm.

JohnJ believes that the Denton fossil is T. roemeri and not T. mucronata which doesn't seem to agree with Finsley. Finsley describes the left valve of T. mucronata as: "greatly arched, with a beak curved fairly straight under." It is "[r]ather elongate and narrow for the genus, with deep fold (sulcus) running length of shell. Finsley's photo of T. roemeri has no sulcus, a slightly slanted beak and wider basal flair which is very different than the Denton fossil.

Does Finsley get his descriptions of Texigryphea correct? Is the Finsley book generally good to use or does it need corrections?

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JohnJ

:) The last thing I will ever profess to be is an authority on Texas Cretaceous oysters, but this is my reasoning.

Finsley's guide is an excellent reference that I use regularly. He mentions that T. mucronata / marcoui occurs in the Fredericksburg Division (Lower Cretaceous) and that T. roemeri / graysonana occurs in the Washita Division. (At the time of Finsley's publication, all of the Washita Group was considered in the Lower Cretaceous. Recent research places the Upper / Lower Cretaceous boundary between the Grayson (Del Rio) and the Main Street Formation.)

Akers & Akers also placed these species in the same geologic groups. In North Texas, the difference between the occurrence of T. mucronata and T. roemeri could range as much as 10 million years and several geologic environments. So, it doesn't surprise me that there is some confusion in the early literature, given the varied growth stages of these oysters and how similar they look.

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DPS Ammonite

Thanks JohnJ for your reasoning. I have found Texigrypheas from the Grayson Fm. that look like the photo of T. mucronata that Finsley says is from the Grayson Fm. (Washita division.) Finsley may be confused when he says T. mucronata occurs inthe Fredericksburg division in the earlier part of the book. I agree, IDs on oysters are difficult because of their great variability.

Cheers,

John

Edited by DPS Ammonite

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JohnJ

Thanks JohnJ for your reasoning. I have found Texigrypheas from the Grayson Fm. that look like the photo of T. mucronata that Finsley says is from the Grayson Fm. (Washita division.) Finsley may be confused when he says T. mucronata occurs inthe Fredericksburg division in the earlier part of the book. I agree, IDs on oysters are difficult because of their great variability.

Cheers,

John

I think his text is accurate, but the note under the T. mucronata photo is an error. T. mucronata doesn't occur in the Grayson Fm.; it's a Fredericksburg Group oyster. As in Finsley's text, note the similarity to the T. roemeri (which does occur in the Grayson Fm.) in the Akers figure in post #11. ;)

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