Dimethyldimethyl Hydantoin: An Alternative Fluid for Morphological and Genetic Preservation

Modern taxonomy requires the preservation of biospecimens for both morphological and molecular applications. The utility of a previously identified preservative, dimethyldimethylhydantoin hydantoin (Dekafald^®), to retain both physical diagnostic traits and the DNA integrity of biological specimens remains unknown. Using 439 eggs and 414 larvae from two North American fish species, we compared three hydantoin solutions at different concentrations (5%, 10%, and 20%) with gold standard preservatives (10% buffered formalin, 95% ethanol) to evaluate morphological trait retention up to 90 days, and DNA barcoding success up to 56 days. While the 5% hydantoin solution had the most sequencing success by 56 days, the 10% hydantoin solution was the best multipurpose preservative. Future work should assess the performance of ∼10% hydantoin solution over longer time periods, and its applicability to other taxa such as Arthropoda.