CELL TYPES AS TAXONOMIC CHARACTERS IN APLYSINA (APLYSINIDAE, VERONGIDA)

Abstract

Some sponge groups are known to present a complex taxonomy, commonly associated with few morphological taxonomic characters. Consequently, techniques other than traditional morphology, such as isozymes, DNA fingerprinting and transmission electron microscopy, have been sought to enhance taxonomic diagnoses. Nevertheless, most require expensive equipment and time consuming procedures. In this work we used a simple technique, based on the characterization of definite cell types, to differentiate two species: Aplysina caissara and Aplysina fulva. Both show similar external and internal morphology, principally on smaller individuals, leading to erroneous identifications. Three shared cell types were used, namely spherulous cell I, spherulous cell II, and microgranular cell. Both species can be clearly identified based on characteristics of these cell types (general size and diversity of inclusions). The results show that the morphology of definite cell types, as observed on simple cytospins, can be an additional taxonomic character to the differentiation of cryptic species.