Abstract

Molluscan shells are widely used for ornamental and scientific purposes, yet their preservation quality varies depending on specimen processing methods. As shells are increasingly recognized as substrates providing morphological, chemical, and molecular information, the selection of appropriate processing strategies has become increasingly important. This study compared shell preservation characteristics of Anadara broughtonii under different specimen processing methods to identify relatively stable treatment conditions. Experimental groups included a water-rinsed control, natural decomposition in water followed by rinsing, ethanol fixation at 70-75% and ≥ 99%, and hot-water treatment applied at the stages of adductor muscle relaxation and soft tissue removal. Shell external structures, periostracum retention, cracking patterns, and inner surface preservation were assessed using stereomicroscopy combined with image focus stacking. Preservation outcomes differed among treatments, particularly in external appearance and periostracum retention. Overall, ethanol fixation at 70-75% was identified as a relatively stable processing method when both preservation quality and practical handling were considered. These findings highlight the importance of selecting specimen processing methods according to the intended use of molluscan shell specimens and provide baseline information for establishing preservation strategies for ornamental collections and morphological research.