Plastination of marine invertebrates: hits and misses

Despite being considered a paraphyletic group, the invertebrates are the most diverse group in the Animalia kingdom. The study of the morphology of these animals is fundamental in knowledge of ecology, habits, taxonomy and in applied research. Most commonly, conservation of invertebrates is done with a solution of 75-95% ethanol or 4-10% formalin. Plastination, a modern and innovative technique, promotes the replacement of tissue water with a curable polymer and produces non-toxic, dry, more resistant and easy-to-maintain specimens. However, the application of the technique to marine invertebrates for tissue conservation was not found in the literature. The objective of this work was to develop a plastination protocol for marine invertebrates, seeking to maintain the most natural appearance possible. In the study, 94 marine invertebrates from different phyla were used and the protocol was followed: anesthesia with magnesium chloride, fixation with 5% formalin, dehydration in pure acetone, impregnation with silicone at room temperature and application of the catalyst to curing the polymer. In general, after plastination, the 94 processed invertebrates were more resistant, durable, easier to handle and maintain, and without toxicity. No major changes in shape, size, or coloration were evident in the animals, except for porifera that lost their pigments and cnidarians that lost part of their volumes. The research results were excellent, with the production of high-quality material, enabling a wide range of applicability of the specimens, whether in the areas of education, research, or exposition.