This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: New research is shedding light on the diversity of deep-sea siphonophores. A team of scientists from MBARI, the University of Gdańsk, New York University and Yale University conducted a comprehensive examination of Bargmannia siphonophores using museum material, submersible observations and genomic sequencing.
This work uncovered two previously unknown species: Bargmannia marlena and Bargmannia pyrosa. The team published their findings in the Zoological Journal of the Linnean Society last week. Siphonophores are elongate gelatinous animals related to jellies and corals that are some of the most dominant predators in the ocean's midwater, the open water between the surface and the seafloor.
Despite their abundance and important ecological roles, siphonophores remain challenging to study. Advanced underwater technology allows scientists in MBARI's Biodiversity and Biooptics Team to observe the anatomy and behavior of deep-sea siphonophores in their natural environment and gently collect these delicate animals for further study in the lab. Bargmannia are among the most streamlined siphonophores, propelled by dozens of swimming bells that jet in unison.
MBARI scientists and their collaborators conducted a comprehensive examination of this widely distributed group of deep-sea siphonophores. They documented the physical features of museum specimens, cataloged habitat data from in situ observations with underwater robots and extracted DNA for genomic sequencing. The team was able to sequence DNA from a historical museum specimen that had been preserved in formalin.
This integrative approach allowed the team to resolve historical taxonomic ambiguities that underestimated the true diversity within this group of deep-sea siphonophores. The team identified seven Bargmannia species in MBARI's extensive video archive, with an eighth species identified from museum collections. Two of these species—Bargmannia marlena with stretchy orange stomachs and Bargmannia pyrosa with a fiery red body—were previously unknown to science.
The eight species represent two evolutionary lineages. While they overlap geographically, their distributions are structured along depth gradients, demonstrating how species evolve across a three-dimensional aquatic environment. Maciej K Mańko et al., Integrating mitogenomes, morphology, and ecology reveals depth-structured diversification and two new species of deep-sea Bargmannia siphonophores (Cnidaria: Hydrozoa), Zoological Journal of the Linnean Society (2026).
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