VAN DER HAM, J.L.*; FELGENHAUER, B.E.; Univ. of Louisiana at Lafayette; Univ. of Louisiana at Lafayette: The Comparative Ultrastructure of the Aesthetascs of Speleonectes tanumekes (Crustacea, Remipedia) and Crustaceans from Stressful Environments.

Osmotic stress of the freshwater environment may have a shortening effect on the length of crustacean aesthetascs. Desiccation associated with the terrestrial and physical stress of the littoral environment may have a similar effect on the length of aesthetascs. The aesthetascs of crustaceans that occur in these environments share similar ultrastructural features which may allow them to cope with these environmental stresses. These ultrastructural similarities are absent from the aesthetascs of crustaceans that occur in the typical marine environment. Interestingly, these ultrastructural aspects are present in the aesthetascs of Speleonectes tanumekes, even though the environmental stresses that may shorten the length of the aesthetascs are absent in the marine cave environment where this animal occurs. This research describes the ultrastructure of the aesthetascs of S. tanumekes and discusses the differences in selective pressures that may result in ultrastructural similarities of aesthetascs of crustacean across various environments.