Studies on the composition and variation of types of nematocysts of the scyphomedusa species Lychnorhiza lucerna Haeckel, 1880 throughout the life cycle

• Grant number: 23/02214-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2023
• End date: April 30, 2024
• Field of knowledge: Biological Sciences - Zoology - Morphology of Recent Groups
• Principal Investigator: André Carrara Morandini
• Grantee: Fernanda Ramos Sandrini
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Critical to the survival of cnidarians, cnidae are cellular organelles secreted by the Golgi apparatus of cells called cnidocytes. These organelles have a capsule and an eversible filament, which can be adorned with spines, and works like a projectile in response to certain stimuli. When in contact with preys and predators, the cnida filament is eversed, stinging and immobilizing them and, in most cases, injecting toxins. The presence of the cnida is a synapomorphic feature of cnidarians, occurring in all members of the phylum, and this reflects on the great diversity of types. In general, there are three main types based on their morphologies, and among them, only nematocysts are present in all cnidarians. Altogether, about 30 types of nematocysts have been described, and the characterization and distribution in a specimen throughout its life cycle, the cnidome, is an important taxonomic character. Among the cnidarians, the subphylum Medusozoa harbors representatives that, in general, exhibit a metagenetic life cycle, with larvae, polyp and medusae stages. Each of these life stages has particularities in their food webs, which provide different types, proportions and distributions of nematocysts throughout the life cycle. The goal of this project is to investigate the cnidome of the species Lychnorhiza lucerna (Scyphozoa: Rhizostomeae) which is the most common jellyfish species along the Brazilian coast. Thus, we intend to study, throughout the life cycle, which nematocysts L. lucerna have and how they are distributed in the body of this jellyfish species. In addition, a comparison will be made between the cnidome of jellyfish specimens grown in laboratory and animals collected in the natural environment, in order to understand if there are differences between them.