Nearly 500 species of deep-sea dwellers documented at Costa Rican methane seeps

An international team of marine biologists has documented the highest known count of deep-sea species living in methane seeps off Costa Rica's Pacific coast.
In a new study in ZooKeys, the team presents a comprehensive catalogue of deep-sea biodiversity—mostly invertebrates—discovered during five research expeditions and 63 submersible dives to Costa Rica's Pacific margin between 2009 and 2019. Through the collection of specimens, photographs, and DNA sequences, the researchers identified 488 distinct species—marking the highest biodiversity count ever recorded in a single seep or vent region.
Of the documented species, 131 are previously described, at least 58 are entirely new to science, and the remainder have some degree of taxonomic uncertainty, likely representing additional undescribed species.
This project was led by UC San Diego's Scripps Institution of Oceanography in collaboration with the University of Costa Rica and its Museum of Zoology. It brought together 28 authors from 22 research organizations from around the world to advance our understanding of deep-sea ecosystems and biodiversity.

"We hope that this information-rich, freely available resource will strengthen deep-sea biodiversity research, education, and conservation, as well as set a high scientific standard to inspire similarly comprehensive studies for other parts of the world," said lead author Charlotte Seid, a senior museum scientist and manager of the Benthic Invertebrate Collection at Scripps Institution of Oceanography.
More information: Charlotte A. Seid et al, A faunal inventory of methane seeps on the Pacific margin of Costa Rica, ZooKeys (2025).
Journal information: ZooKeys
Provided by University of California - San Diego