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A team with the participation of CABD identifies four different species of bluebottles or man-o'-war

Scientists have sequenced the genome of 151 specimens of this marine organism and have analyzed 4,000 photographs

The research represents a further step towards understanding the evolutionary processes occurring in the open ocean



An international study involving the Andalusian Center for Developmental Biology (CABD-CSIC-UPO-JA) and the Institute of Marine Sciences of Andalusia (ICMAN-CSIC) has identified four different species of bluebottles or man-o'-war after sequencing the genome of 151 specimens and analyzing 4,000 images shared on iNaturalist, a global community of photographs taken by naturalists, scientists and the general public. The results, published in the journal Current Biology, show that this gelatinous marine organism is actually divided into four distinct species with different geographic distributions: Physalia physalis, Physalia utriculus, Physalia megalista, and Physalia minuta.

Although it is often confused with a jellyfish, the Portuguese dogfish is an organism called a colonial hydrozoan, formed by hundreds of specialized individuals that work together as if they were a single living being. Its most striking feature is its sail-like gelatinous float that allows it to move with the currents. Their stinging cells can cause painful stings.

A connected marine environment

The research may contribute to understanding the evolutionary processes occurring in the open ocean. The study indicates that, although the ocean can be understood as an environment without physical divisions, this characteristic is not a condition that limits genetic differentiation in organisms with the capacity for large-scale dispersal. 
It suggests that, contrary to popular belief, uniform populations are the exception rather than the rule in marine invertebrates. Moreover, it revalidates old taxonomic hypotheses that had been discarded, since three of the proposed species correspond to classifications made in the 18th and 11th centuries.
“This finding has been possible thanks to an immense effort to collect specimens all over the world, which has revealed the existence of different species and genetic characteristics,” said Ozren Bogdanovic, CABD researcher and one of the authors of the study.
"This work is relevant because it transforms the understanding of connectivity in the marine environment. In addition, it may have important implications for the conservation and management of species, as it allows us to identify local populations whose management may require more specific measures than if they were treated as a single global population," says Laura Prieto, leader of the research on gelatinous organisms carried out at the ICMAN-CSIC.

This press release was made in collaboration with the Communication Department of CSIC and CSIC Andalucía.