Cambrian fossils shed light on the unusual shells of lingulid brachiopods

[Halichoeres]

Lingulid brachiopods are weird among brachiopods, both for the shape of their shells, as well as the composition. Instead of calcium carbonate like any respectable marine invertebrate, they use calcium phosphate, and have done so for 500 million years. That makes their shells more similar in composition to our bones than to other brachiopod shells, and it might also be one reason they're among the few brachiopod lineages to survive all the extinction events that clobbered other marine organisms. Anyway, this new paper does some really detailed analysis of some fossilized lingulid shells, and describes a new genus (Latusobolus) and two new species from the Cambrian of China. The writing is a little bit turgid, maybe partly to make up for the fact that they describe the architecture of the shells as "stacked sandwiches!"

Some really nice micrographs of the stacked sandwiches:


I might have called them stacked quesadillas!

Open access in elife: https://elifesciences.org/articles/88855

[ceratopsian]

"Stacked sandwiches" is a phrase I won't forget in a hurry.

[Papi-Anon]

Are we certain those are close-ups of brachiopod shell fossils and not old black-and-white photos of archeological ruins?

In a serious note, the different chemical composition of their shells compared to most shelled sea life correlating with their ability to survive even the Permian is a fascinating thing to consider.