What are 'articulate shells'?

Question

I can not really find a definition, not even in a geologic dictionnary: What are articulate (resp. inarticulate) shells?To be more specific, the term is related to tsunami deposits (tsunamite).

Answer 1

Hello! In regards to Paleontology, there are two categories of Brachiopods; articulate and inarticulate. Articulate brachiopods have simple muscles for opening and closing their valves and their hinges are toothed. Inarticulate have untoothed hinges and more complex muscles for the opening/ closing of their valves. Hopes this helps!