This was sold to me as a Derasa, which was one of the species that fit my tank positioning (high light, but a clam that was happy being on the sand bed with proper rock to adhere to).
After getting it home and reading more about Derasa clams it appears this may not be one, based on the ribbing on the shell. Your opinion on ID is welcome.
It is a rather dull brown/black/gold coloration on the mantle with 5 scallops. I can get top downs fully open if that would help.
