Amino acid racemization in four species of ostracodes: Taxonomic, environmental, and microstructural controls

► At low D/L values ostracode genera showed different racemization rates. ► Ostracode genera showed similar rates at high D/L values, except Ilyocypris gibba. ► These differences likely to be due to the variations in valve protein composition. ► Microstructure of the valves of each species differed. ► Such differences may be linked to the type of proteins involved in the calcification process.