ID thck bivalve with spines

[Kcee]

I have been told by a scientist that this belongs to a cockle but I'm having a very hard time seeing it as one. I have found several bivalves on line that have spines but can't find an exact match for the pattern on this thing. The thick section is a little over 5mm and the thin section is about 2mm. It does not slope down to 2mm it has steps in it, which I can't find on any bivalves on line. Also, the spines on all bivalves I've seen appear to fan out as they move from the rear (hinge area) to the thinner forward area but these spines are coming together at what appears to be the thinner area and fanning out at the thick section.

Has anyone ever seen anything like this???

[Fossildude19]

@MikeR  @Coco  @belemniten

[Coco]

Hi,

 

I can't help, sorry.

 

Coco

[FranzBernhard]

Could be Anadara (arc clam):

Edit: MikeR proved me wrong, thanks  (see below).

 

https://www.franzbernhard.lima-city.de/Anadara_Intertidal.html

 

http://www.thefossilforum.com/uploads/monthly_2019_05/Anadara_Fuggaberg6_2_mitBeschriftung_kompr.thumb.jpg.8f07eec732306360d16f9c649492c8a6.jpg

 

Franz Bernhard

Edited August 12, 2019 by FranzBernhard

[Pemphix]

I think FranzBernhard is close to the solution...

Would be good to know from which area and stratigraphic member it comes.

Would make determination easier...

[DPS Ammonite]

It is similar to the modern Blood Cockle, Anadara granosa.

 

See: http://www.fao.org/fishery/species/3503/en

[JohnBrewer]

@maxfossil

[MikeR]

If it is from California, it is not Anadara granosa which is an Indo-Pacific species.  It is indeed part of a cockle bivalve shell.  I would lean towards Clinocardium nuttalli.  The two below that I collected are from the Upper Pleistocene of Santa Barbara County, California, but it probably ranges into the Pliocene.

 

Mike

 

[Kcee]

Thanks everyone, this one was picked up from the California desert and I do believe it is from the Pliocene period. The pattern matches the one that MikeR has but I do think it might be closer to the one in the first link that FranzBernhard posted. I wasn't sure if the parts in the photos below belonged to this specimen but after seeing the ones in that link, I do think they are part of this bivalve now. About how big do this specimen get?

Thanks a million

[FranzBernhard]

Strange! Is this the teeth area (more probably) or the rim/commisure (less probably) of a bivalve? If it is the teeth area, this fragment does not belong to a "cardium". Its more like an arcaid or glycymerid bivalve

But we don´t know for sure, if the large fragment belongs to the same species as the small fragment to the left .

Are you able to expose the hinge/teeth area of the large fragment (if there is any left)? And what is known in the area/formation you have collected these?

@MikeR, @DPS Ammonite, @Max-fossils, @Kcee

Franz Bernhard

[DPS Ammonite]

Here is a picture of an Anadara from SE USA from Neogene Atlas. The teeth look similar to those of the poster’s fossil.

 

https://neogeneatlas.net/species/anadara-alumensis/

[MikeR]

I agree with Franz that there is a Glycymeris hinge pictured however I do not believe it is of the other specimen as I know of no Glycymerid thus ornamented.  It cannot be the same species of the Anadara put forth (Indo-Pacific, Austrian Miocene or SE USA) due to location.  Cenozoic marine faunas always show a relatedness to extant faunas.  Although difficult for a fragment, if nothing more than the County in California where it was found will go a long way in researching what it is.

 

Mike

[Kcee]

This stone was picked up near Palmdale, Ca. It was just laying out in the open with about 5 other sandstones. It was found in an area that I am told is not known for producing any fossils at all. Here's some photos of that large piece after being cleaned up a bit more, hope this helps. 

If you look at the first 5 photos I posted, the last 2 show a step, what is that step, I can't seem to make out where it would be when I look at the other bivalves shown.

[Max-fossils]

On 8/11/2019 at 2:28 AM, Kcee said:

If you compare the sculpture on this piece here to the sculpture on these, I really don't think they match. For one, the 'knobbles' on the OP's post are much more pronounced, and secondly (and more strikingly), the spaces in between the radial ridges are much wider. So I disagree with @MikeR's ID (sorry Mike).

On 8/12/2019 at 3:57 PM, MikeR said:

However, although Anadara granulosa fits much better sculpture-wise, Mike's point on the location is still true too. While it may then be from a shell within that genus, Mike wasn't totally wrong proposing a member from the Cardiidae family as many from that family do show a kinda similar sculpture. So do many from the Arcidae family (of which Anadara is a part of). The Carditidae family also comes to mind. All of these families have some members with a sculpture quite similar to this (thick knobbled concentric ridges with wide spaces in between). And seeing that this is apparently a location that hasn't been documented yet (a quick Google search also delivers no results):

On 8/14/2019 at 5:07 AM, Kcee said:

is not known for producing any fossils at all.

this means that it will be very difficult to find the age and formation of these fossils and find relevant papers of the bivalve fauna there. 

So even though I hate to say this, I'm afraid it's gonna be very difficult to actually put an ID from just this fragment.  

 

Also, about that last fragment, I have never seen something like it, it's so weird! Unless I'm missing something, it doesn't look like a hinge fragment to me...

[Kcee]

Thought for a moment there that I would be able to take these items off the "Mystery List". Thanks for all the great intel everyone, I'm learning a great deal being on here. I'll keep poking at these items and if I find someone out there who can say for certain what these items belong to, I will for sure post that info on here.

Thanks

[Kcee]

On 8/15/2019 at 3:57 AM, Max-fossils said:

Also, about that last fragment, I have never seen something like it, it's so weird! Unless I'm missing something, it doesn't look like a hinge fragment to me...

Well, looks like you were 100% correct about that piece. Not sure what it is but like you, I'm sure it does not belong to a bivalve. I have showed this stuff to a number of scientist and no one can make a positive ID, still searching....