![\"This](\"https:\/\/cdn.sci.news\/images\/enlarge11\/image_12263_1e-Gulf-Alaska-Object.jpg\")
<\/a><\/p>\nThis \u2018golden orb\u2019 was found at a depth of about 3,300 m in the Gulf of Alaska. Image credit: NOAA Ocean Exploration, Seascape Alaska.<\/p>\n
The \u2018golden orb<\/a>\u2019 was collected on August 30, 2023, by the remotely operated vehicle Deep Discoverer, launched from the U.S. exploration vessel Okeanos Explorer.<\/p>\n Around 10 cm (4 inches) across, the mysterious object was found among small glass sponges on the seafloor southwest of Walker Seamount in the Gulf of Alaska.<\/p>\n Its smooth, metallic sheen and torn opening quickly sparked speculation about its origin.<\/p>\n \u201cInitial examination of the gross morphology revealed the specimen to have no indication of typical animal anatomy (mouth, gut, muscle tissues, etc.), but rather to consist of a loose aggregation of fibrous material covered by a smooth, layered surface,\u201d said study first author Dr. Steven Auscavitch and colleagues.<\/p>\n Further examination under light microscopy revealed that the surface was packed with specialized stinging structures unique to Hexacorallia<\/a>, a group of cnidarians that includes sea anemones and stony corals.<\/p>\n Relicanthus daphneae has pale purple or pink tentacles that can extend almost 2.1 m (7 feet) long. Image credit: Craig Smith & Diva Amon, ABYSSLINE Project.<\/p>\n The researchers also examined a similar specimen collected in 2021 during an expedition on Schmidt Ocean Institute\u2019s Research Vessel Falkor and found similar stinging structures.<\/p>\n Genetic analysis confirmed the connection: DNA recovered from the \u2018golden orb\u2019 matched Relicanthus daphneae<\/a>, an enigmatic deep-sea anemone species known for its large size and long, flowing tentacles.<\/p>\n Together, the evidence pointed to a surprising conclusion: the \u2018golden orb\u2019 was not a living organism but a biological remnant that formed at the base of the anemone.<\/p>\n The specimen was the part of a Relicanthus daphneae individual that attached to the rock substrate.<\/p>\n \u201cThe specimen represents a novel microhabitat consisting of a remnant cuticle originally secreted by Relicanthus daphneae, itself a rarely encountered and recently described species, which occurs between 1,200 and 4,000 m (0.75-2.5 miles), and microbial community living on and beneath its cuticle and tissue,\u201d the scientists said.<\/p>\n \u201cThese significant discoveries enabled by collection would have been unlikely were it not for its unusual golden color and the specimen\u2019s mysterious egg-like appearance.\u201d<\/p>\n This Relicanthus daphneae was observed during a 2016 expedition on NOAA Ship Okeanos Explorer in the Mariana Islands region. Image credit: NOAA Ocean Exploration, Deepwater Exploration of the Marianas.<\/p>\n Though seldom collected, Relicanthus daphneae is thought to be globally distributed.<\/p>\n Individual polyps can reach about 30 cm (12 inches) across, with long, sinuous tentacles that may stretch twice that width.<\/p>\n Observations suggest the animals perch on rocks or sponges, extending their tentacles into passing currents to capture prey.<\/p>\n They may also move across the seafloor, potentially leaving behind trails of the same golden cuticle.<\/p>\n Exactly why they shed this material remains uncertain. One possibility is a form of asexual reproduction known as pedal laceration<\/a>.<\/p>\n \u201cOur findings underscore the extent to which the biodiversity and organismal biology of obscure deep sea fauna broadly remain unresolved and highlight the value of whole-specimen collections and rigorous taxonomic follow-up in telepresence-enabled ocean exploration,\u201d the authors concluded.<\/p>\n<\/a><\/p>\n<\/a><\/p>\n