Tightly shut: flexible valve margins and microstructural asymmetry in pterioid bivalves

Funding was provided by projects CGL2013-48247-P and CGL 2017-85118-P of the Spanish Ministerio de Ciencia e Innovacion. A.G.C. also acknowledges the Research Group RNM363 (Junta de Andalucia) and the Unidad Cientifica de Excelencia UCE-PP2016-05 of the University of Granada for financial support. We are grateful to Philippe Maestrati for access to the MNHN collections, Mercedes Checa for assistance with measurements and the constructive comments of two reviewers.