The new description increases the number of known species in the jellyfish genus from seven to 28 (2023)

With diameters ranging from 10 cm (about the size of a dinner plate) to 46 cm (the size of a large platter), the moon jellyfishAureliospp. it is almost entirely translucent, with a bluish or pinkish tinge, and is found in coastal environments throughout the world. Seven species were recognized until recently, but a study by researchers in Brazil, Argentina, and the United States has now brought the number of species in the genus to 28.

The results of the study arereportedIn the diaryPeerJ. Descriptions are essential for new research onAurelio, one of the most studied genera of jellyfish. Species delimitation also contributes to conservation strategies amid environmental changes brought about by the climate crisis.

“The initial proposal was to try to understand what was happening with these animals along the Brazilian coast, but it expanded when I had the opportunity to analyze the genus worldwide. It became clear that the matter was more complex and required an understanding of the global context before we could establish which species are found in Brazil,” he said.jonathan leyley, first author of the published article. The study was part of his master's research at the Institute of Biosciences of the University of São Paulo (IB-USP) in Brazil with agrant from FAPESP.

He did part of the research at the National Museum of Natural History of the Smithsonian Institution in the United States, also withFAPESP's support. He was able to analyze the large collection at the museum in Washington DC, which includes specimens collected from all over the world. While working at the Smithsonian, he also received deposited specimens from other US institutions. Separately, he traveled to Denmark to analyze specimens at the Museum of Zoology at the University of Copenhagen. He realized that differentiation would be impossible based on morphology alone. Although many of the animals showed no morphological differences at all, genetic analysis showed that they belonged to different species.

“Studying jellyfish is not easy. The body has only a hard structure and is unlikely to remain intact for a long period of time for action to be taken. Being gelatinous, they can shrink up to 40% when preserved, since they contain a lot of water. Another important factor is that some species are very similar," he said.Andre Morandini, last author of the published article. Morandini is a professor at IB-USP and vice director of the Center for Marine Biology (CEBIMAR-USP) in São Sebastião, São Paulo state.

The study was part of the project financed by FAPESP“Recognition of the diversity of jellyfish (Medusozoa, Rhopaliophora)”, with Morandini as principal investigator.

genetics

The study has contributed to a debate going back more than 200 years about the number of species in the genus.Aurelio. The first species recognized by modern taxonomy wasgolden aurelia, described in 1758 by Linnaeus (Swedish naturalist Carl von Linné, 1707-1778).

Other descriptions were produced, increasing the number of proposed species from eight to 13, although some were later invalidated. At the beginning of this century, three had been accepted as valid in addition toA. golden. These wereA. labiata, which has a distinct mouth that resembles a human lip;A. limbata, found in the Arctic, with a brown bell margin; andA. marginalis, which occurs in the Gulf of Mexico and the eastern United States.

In 2016 genetic tools were used to recognize three more species,A. coerulea,A leftyA. solid, all occurring in the Mediterranean. Others were delimited with molecular markers but not formally described because the available morphological data were insufficient to compare them with the genetic data.

This latest study combined morphological data with four molecular markers derived from mitochondrial and nuclear DNA. In some cases, the difference corresponded to only 5% of the genome.

To answer Lawley's initial question, three species were identified on the Brazilian coast. Previously they were considered to be only one,A. golden.

A. insulariaIt is found mainly on islands in the southeast and south of Brazil, such as Ilha Grande, as well as in the United States (Key Largo, Florida).

A. mianzaniit is named after Hermes W. Mianzan (1957-2014), an Argentine researcher who collected some of the specimens that have had their DNA sequenced and contributed significantly to studies of jellyfish in the Southwest Atlantic. The species is found in Praia do Segredo in São Sebastião and in Samborombón Bay in Buenos Aires Province, Argentina.

A. cebimarensis bears the name of CEBIMAR-USP, to which the Brazilian researchers involved in the study are affiliated. The specimen that served as a reference for the description was found in São Sebastião in Ponta do Baleeiro, part of a beach called Praia do Cabelo Gordo, where CEBIMAR is located. The species probably inhabits most of the Brazilian coast.

Two other species named by specialists in the field areA. Montyiand honor deGuillermo "Monty" Graham, Director of the Florida Institute of Oceanography, andA. miyakei, in honor of Hiroshi Miyake, a professor at Kitasato University in Japan.

The other newly named species areA rara,A. ayla,A. smithsoniana,a. colombiayA. malayensis. Additionally, four species have been resurrected:A. persea, invalidated after being described in the 18th century, andto closed,A. DoubtsyA. hyaline, originally described in the 19th century and later invalidated. Another seven remain formally undescribed as only genetic data are available and they have not been characterized on the basis of morphology.

"Our study recognizes the diversity of the genus and will help show, for example, how each species responds to certain processes, which ones are from a locality and which ones have been introduced, among other things," said Lawley, who is currently involved in research PhD at Griffith University in Australia.

“Our laboratory has specimens that live at 30 °C and others that live at 10 °C. We now know that they are not the same species. One of the developments of this study that is in progress is an investigation of their reproductive patterns to see how different species respond to environmental variations and how this will be influenced by factors associated with climate change," said Morandini, co-author.world atlas of jellyfish, published in 2019.

The research also has the support of FAPESP through anotherproject, whose principal investigator issergio stamp, professor at the Faculty of Sciences and Letters of the State University of São Paulo (FCL-UNESP) in Assis, and through abeca postdoctoralawarded toMaximilian Marona, IB-USP researcher. Both are co-authors ofPeerJarticle.

About the São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution whose mission is to support scientific research in all fields of knowledge by granting scholarships, grants and grants to researchers linked to State higher education and research institutions. from Sao Paulo, Brazil. FAPESP is aware that the best research can only be done by working with the best international researchers. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP atwww.fapesp.br/esand visit the FAPESP news agency atwww.agencia.fapesp.br/eskeep up to date with the latest scientific advances that FAPESP helps to achieve through its numerous programs, awards and research centers. You can also subscribe to the FAPESP news agency athttp://agencia.fapesp.br/subscribe.