Can someone help to identify these fossils and the possible date of age?

[PatriciaL]

I've found this mollusc fossils in the Saudi Arabia desert, one hour away from Riyadh city. 
It seems all this area was ocean during the the early cretaceous period.
Meaning that these fossils can have around 77 million years old? They are bigger than a tennis ball!
Can someone help to identify these exactly and the possible date of age?

Thank you!

[rocket]

could you please post some pics as jpg?

Not easy for everyone with heic-files

Thanks a lot!

[PatriciaL]

Here is some additional images

 

[Ludwigia]

These all appear to be bivalves, mostly steinkerns with a bit of shell remnants here and there. Possibly Pholadomya. Determining the exact age of this genus is difficult, since these bivalves cover a lot of stratigraphic ground. If you know the exact location, then you could try to research the stratigraphy, which would in turn give you the age, but if you've already been able to narrow it down to Early Cretaceous and 77 million years, then that's probably as close as you're going to get.

[deltav2]

1 hour ago, Ludwigia said:

These all appear to be bivalves, mostly steinkerns with a bit of shell remnants here and there. Possibly Pholadomya. Determining the exact age of this genus is difficult, since these bivalves cover a lot of stratigraphic ground. If you know the exact location, then you could try to research the stratigraphy, which would in turn give you the age, but if you've already been able to narrow it down to Early Cretaceous and 77 million years, then that's probably as close as you're going to get.

I think the shell remnant is a preserved oyster, I found some examples from the same location here: https://www.instagram.com/p/CQ_RO9BN0Ml/?utm_source=ig_web_copy_link&igsh=MzRlODBiNWFlZA==

 

[Ludwigia]

I mean the steinkerns are Pholadomya not the shell remnant.