Detailed information on 958 distinct morphological types of jellyfish that inhabit the Atlantic and Pacific coasts of South America has been compiled in a study involving scientists from Argentina, Chile, Peru, Colombia and Uruguay. The census, considered the world's largest for this group of animals, was published in the Zootaxa journal.
The project was coordinated by Antonio Carlos Marques, a professor at the University of São Paulo's Biosciences Institute and director of its Marine Biology Center, and Otto Muller Patrão de Oliveira, a professor at the Federal University of the ABC.
"The compilation presented in the article includes animals belonging to the phyla Ctenophora and Cnidaria. The former are commonly known as comb jellies and include jellyfish whose kinship with other animal groups is unclear. The latter include hydras, medusae, polyps, corals and sea anemones. However, the only species of Cnidaria included are from the subphylum Medusozoa, whose life cycle has a medusa, or jellyfish, phase," Marques explained.
The census lists 958 morphotypes–800 of them identified as unique species based on their morphology. For each, information is provided on areas of occurrence; previous records produced by other researchers, ecological data such as type of habitat, water depth, and attachment substrate in the benthic phase.
Data collection covered the entire continent, from the equatorial waters of Colombia's Caribbean coast to the subpolar region of Tierra del Fuego in Argentina, and included the mouth of the Amazon River, the entire coast of Brazil, and the entire Pacific coast of South America.
Besides reviewing scientific literature, the researchers also included data on thousands of specimens held by zoology museums and other institutions dedicated to the conservation of knowledge about marine organisms.
Much of the information have been collected by the authors during oceanographic cruises. "We took the trouble of retrieving these collections and studying each of the specimens. The collections contain a wealth of material, and access to them is important. A sizable proportion of the data had never been published. Now, we have an enormous amount of organized information that can serve as a basis for many future investigations,” said Marques.
Besides helping researchers understand the evolution and diversification of these animals, the census project can help to identify the areas that require conservation measures.
"As a result of this project, scientists are able to decide which areas have the most species, the greatest taxonomic complexity in the sense of having species in many different groups, and the most endemic species, which occur only in certain areas, as well as any isolated populations. In conjunction with a geographical perspective, this knowledge will enable policymakers to establish priority areas for conservation based at least on data for cnidarians," Marques said.
More information and new data will be included as the scientists continue their research in underexplored parts of South America. "The census has taken on a life of its own," he said. "It will continue to grow, and the database will be continually upgraded and refined."