Rudist ?

[fifbrindacier 3,408]

Hi, a friend of mine told me he found some Placentyceras in a place where the geologic ages go from the Albian to the Turonian-Santonian, but most of the stratas of that place are Cenomanian.

I believe this fossil is not an ammonite, but rather an Oyster or a rudist. I mostly think about Requienia or Toucasia. The geologic file mention the name of Toncasia bayleia.

Do you know if Toncasia is a synonym of Toucasia and do you think i'm right thinking this is a rudist ?

Lenght : 7 centimeters.

[Fossildude19 10,892]

Is there a reason to discount the possibility of being an oyster, such as Gryphaea or Exogyra? 

The ridges look a bit more 3 dimensional than the images I see of the other options. 

[fifbrindacier 3,408]

You're right, i've mentioned this possibility in the tags but not in the post, i've edited it.

[Fossildude19 10,892]

Oops! I always forget to look there! 

[DPS Ammonite 2,453]

I cannot see in the pictures where they show if this is an oyster or a rudist that is more like a gastropod. If it is an oyster you should be able to see where the two shells meet or you should be able to see the concave interior of a single shell.

 

If it is a rudist, you should be able to see a small opening with a deeply invaginated interior similar to a snail. You might also see a small shell covering the opening.

 

Please show us the other side (back side) of this:

 

 

@fifbrindacier Are you able to see and send us a clear photo of where two shells meet if this is an oyster or of the small opening if this is a rudist?

 

What does our rudist expert think? @FranzBernhard

[FranzBernhard 1,471]

Thanks, @DPS Ammonite, but I am not an expert.

 

Googling for Toucasia yields some examples, also this one:

http://le-coin-a-fossiles.fr/barremien.html

 

2 hours ago, fifbrindacier said:

Do you know if Toncasia is a synonym of Toucasia

Its just a typical misreading, n for u.

 

Tried googling for -- toucasia bayleia --, but without quotation marks. Yields an old work, bayleia seems to be the name of a genus or subgenus - ? Oh yes, its a genus within the family Requieniidae.

 

But, sorry, I don´t know what your specimen is .

 

Franz Bernhard

[caterpillar 498]

Take a look at Amphidonte

[fifbrindacier 3,408]

21 hours ago, caterpillar said:

Take a look at Amphidonte

I did, and i agree this fits well. I should have listen to my first impression it was an Oyster. Thank you Caterpillar.

[doushantuo 4,036]

[fifbrindacier 3,408]

Thank you @doushantuo

[Fossildude19 10,892]

12 minutes ago, doushantuo said:

What paper is this from, Ben? 

[doushantuo 4,036]

Not entirely sure,but it MIGHT be from Klaus Bandel,around 1993 ,in the Mitteilungen des Geologisches-Palaontologisches Instituts/Univ.Hamburg

[piranha 5,561]

2 hours ago, doushantuo said:

Not entirely sure,but it MIGHT be from Klaus Bandel,around 1993 ,in the Mitteilungen des Geologisches-Palaontologisches Instituts/Univ.Hamburg

 

 

MIGHT be or it is not? ...why all the intrigue?  LINK

 

The paper is actually by:

 

Mohammad Aqrabawi Amman 1993

Oysters (Bivalvia-Pteriomorphia) of the Upper Cretaceous rocks of Jordan. Palaeontology, Stratigraphy and Comparison with the Upper Cretaceous oysters of Northwest Europe.

Mitteilungen aus dem Mineralogisch-Geologischen Institut in Hamburg, 75:1-135

[will stevenson 264]

Definitely exogyra I have one myself

[fifbrindacier 3,408]

40 minutes ago, will stevenson said:

Definitely exogyra I have one myself

 

2 hours ago, piranha said:

 

 

MIGHT be or it is not? ...why all the intrigue?  LINK

 

The paper is actually by:

 

Mohammad Aqrabawi Amman 1993

Oysters (Bivalvia-Pteriomorphia) of the Upper Cretaceous rocks of Jordan. Palaeontology, Stratigraphy and Comparison with the Upper Cretaceous oysters of Northwest Europe.

Mitteilungen aus dem Mineralogisch-Geologischen Institut in Hamburg, 75:1-135

Thank you all !