Presenting the "Golden Orb" discovery at the 9th International Symposium on Deep-Sea Corals
October 30, 2026
This weekend I'm traveling to Barcelona, Spain, for the 9th International Symposium on Deep-Sea Corals (9th ISDSC), running November 2–5, 2026. This is the first time the symposium has been hosted on the Mediterranean Sea. It is co-organized by the Universitat de Barcelona, the Instituto Español de Oceanografía (IEO-CSIC), and the Institut de Recerca de la Biodiversitat (IRBio).
This year's meeting carries the theme Science, Art and Society. Alongside the scientific program, the organizers have built in a dedicated art–science program, which feels fitting for a field that depends so heavily on public engagement with ocean exploration.
It has been three and a half years since I presented at the 8th ISDSC in Edinburgh, and I'm looking forward to reconnecting with the deep-sea coral community and seeing how much the field has moved since then.
The poster: what the "Golden Orb" taught us
I'll be presenting a poster in the Biology and Ecology theme entitled "All That Glitters: Resolving the 'Golden Orb' as a Remnant Structure of the Deep-Sea Anemone Relicanthus daphneae and What a Viral Mystery Taught Us About Hexacoral Evolution."
The poster builds on the identification we announced in April. The golden, mound-shaped object recovered from 3,250 m on a Gulf of Alaska seamount by NOAA Ship Okeanos Explorer in 2023 turned out to be the spirocyst-bearing cuticle of R. daphneae. This relict structure was absent from the original species description and had never been documented in collected material.
Since then, the story has grown well beyond the orb itself:
Genetic identity. Complete mitochondrial genomes from the Golden Orb and a second specimen from the central Pacific are 99.9% identical to the published R. daphneae reference.
Hexacoral evolution. Phylogenomic analysis of 94 ultraconserved element loci across 164 anthozoan taxa recovers Relicanthus as sister to a clade uniting Antipatharia, Corallimorpharia, and Scleractinia, offering new resolution at a long-contested node.
A global distribution. Seafloor imagery, targeted collections, and reference databases reveal a cosmopolitan range spanning nearly every major ocean basin, from 1,254 to 3,948 m depth.
How the cuticle is left behind. In situ video from other occurrences suggests Relicanthus deposits its cuticle as it moves across rocky hard substrates.
A microhabitat in its own right. Metagenomic analysis shows the abandoned cuticle hosts a distinct microbial community, including ammonia-oxidizing archaea and diverse heterotrophic bacteria, hinting that it acts as a small biogeochemical hotspot on the seafloor.
The broader message is one I keep returning to: rigorous post-collection integrative taxonomy, paired with a critical look at imagery and database records, is still essential for understanding deep-sea animals. Actiniaria in particular remain among the least characterized members of deep-sea benthic communities, and there is a lot left to learn.
Come find me in Barcelona
The poster will be up during the designated poster sessions on Wednesday, November 4, 2026 (Poster #1, Morning Session). If you're attending, please stop by. I'd love to talk anemones, coral phylogenomics, exploration, or anything else deep sea.
This work was a true team effort, and I'm grateful to my co-authors Abigail Reft, Adena Collens, Chris Mah, Merlin Best, Charlotte Benedict, Estefanía Rodríguez, Marymegan Daly, and Allen Collins. Together they represent the Smithsonian's National Museum of Natural History, NOAA's National Systematics Laboratory, the University of Maryland, Fisheries and Oceans Canada, The Ohio State University, and the American Museum of Natural History.
View the poster
Download the 9th ISDSC poster (PDF) here after November 2, 2026.
Preprint citation: Auscavitch, S. R., Reft, A., Collens, A. B., Mah, C., Best, M., Benedict, C., Rodríguez, E., Daly, M., & Collins, A. G. (2026). The curious case of the Golden Orb – remnant of Relicanthus daphneae (Cnidaria, Anthozoa, Hexacorallia), a deep sea anemone [Preprint]. bioRxiv. https://doi.org/10.64898/2026.04.17.719276
This work has been accepted for publication in PeerJ. I'll update this post with a link to the published article and its final DOI once it is available.