A century of deep-sea exploration has been condensed into a remarkable new scientific resource: the digitized brachiopod collection of the Shirshov Institute of Oceanology of the Russian Academy of Sciences. The dataset documents 3,235 shell-bearing marine animals gathered from 1,852 locations across the World Ocean, with sampling beginning in 1924 and records continuing through 2024. It represents one of the world’s largest repositories of living brachiopods, organisms whose paired shells and stalked bodies make them look superficially like mussels. Brachiopods are not mollusks, however. They constitute their own phylum, and their distribution records an ancient, highly localized branch of marine life that can be difficult to study outside museum drawers. By pairing physical specimens with standardized digital information, the collection offers researchers an unusually broad view of how these animals have been recorded from continental slopes, island waters, and deep ocean trenches over the past century.
The project was led by Olga Nikolaevna Zezina, a Soviet and Russian zoologist and hydrobiologist whose work transformed knowledge of modern brachiopods. She established one of the world’s foremost collections of these animals and used its specimens to investigate their habitats on continental slopes, islands, and underwater elevations. Her work also led to a scheme for biogeographical zoning of the ocean’s bathyal zone, the deep region beyond the reach of sunlight. According to the source article, Zezina demonstrated the role of brachiopods as indicators of the ocean’s natural bottom biofilter below the photic layer and derived empirical information on the balance between production and biomass in deep-sea bottom invertebrates. Her taxonomic legacy is preserved within the material: she described a new family, two subfamilies, 11 genera, 21 species, and three subspecies, while the collection contains 72 type specimens representing 18 species and two subspecies.
Those type specimens are nomenclatural anchors. When a scientist names a new species or establishes a change in classification, a designated physical specimen becomes the formal reference point for the name. Such objects can be decisive in resolving difficult questions about anatomy, geographic variation, and the boundary between similar taxa. They also have practical value: the soundness of a modern identification can be tested against the preserved material on which the original description was based. The digitization effort prioritized documenting and imaging these types, giving researchers a clearer route to locating, comparing, and reusing the collection’s most important reference material. The wider revision also standardizes scientific names through the World Register of Marine Species, reducing ambiguity in records assembled across decades of expeditions.
Most specimens were collected with trawls, grabs, and dredges designed to work across very different seafloor environments. The collection includes 779 lots obtained with Sigsbee trawls, 699 with “Okean” grabs, and 194 with dredges. Overall, 1,267 lots—representing 69% of the collection—came from trawl types, alongside material gathered with bottom and Agassiz trawls, box corers, submersibles, and remotely operated vehicles. The catalogue records the sampling protocol for each event, allowing a specimen to be linked not merely to a place and date but also to the method that brought it to the surface. That distinction matters in marine biology because gear selectivity can influence which organisms are collected at particular depths and on particular substrates. The preserved protocols make it possible to account for sampling bias when comparing historical records.
Geographically, the collection is especially rich in the Arctic and northwestern Pacific. Soviet and Russian research vessels, including the Vityaz, Krylatka, Nikolay Maslov, Atna, and Akademik Kurchatov, supplied much of the material. Important sampling areas include the Sea of Okhotsk, the Norwegian Sea, and the Sea of Japan. Altogether, the records span 248 research voyages, creating a time series of biological observations extending across an era of major changes in oceanographic equipment, political organization, and scientific collaboration. Rather than presenting a collection as a static list of species, the dataset allows researchers to ask when particular taxa were recovered, where they appeared, how deep they occurred, and which methods were used. These records can support comparative studies of distribution, historical collecting effort, and possible shifts in the known geographic ranges of brachiopods.
Depth is one of the collection’s defining strengths. The specimens span all major ocean depth zones, with particularly substantial representation from deep waters: 756 lots come from the bathyal zone and 334 from the abyssal zone. Even more striking are three rare specimens from the ultra-abyssal hadal zone of the Romanche Trench in the northwestern Pacific. Such material comes from environments that are exceptionally difficult to sample and remain poorly represented in global biodiversity databases. Hadal trenches are narrow depressions in the deepest parts of the ocean, and organisms from those sites are often known only from isolated expeditions. The Romanche Trench records therefore provide rare, physical evidence that can help researchers investigate how brachiopods persist under extreme pressure, darkness, and restricted food input. They also offer reference points against which future observations of deep-sea faunal distribution can be compared.
Taxonomically, the collection is unusually broad. It includes 173 species from 96 genera and 30 families, and 88% of its specimens have been identified to species level. The represented families range across the living brachiopod diversity, including Aulacothyropsidae, Basiliolidae, Craniidae, Dallinidae, Discinidae, Obolidae, Rhynchonellidae, Terebratellidae, Terebratulidae and others. The dataset documents preserved material in forms such as ethanol and dried specimens, while its records can also refer to preparations made for scanning electron microscopy or microscope slides. For modern systematics, that combination of physical breadth and digital structure is crucial. Researchers can investigate shell form, internal anatomy, and taxonomic placement while using the catalogue to select relevant material without first needing to sift through an entire museum collection. The result is a reference platform for both specialist identification and large-scale comparative research.
The collection was digitized with Specify 6, software developed for managing natural-history information. Each catalogued lot now includes fields for the scientific name, collection date, geographic coordinates, depth, images, and other relevant metadata. The catalogue was then converted into a Darwin Core occurrence dataset and published through the Global Biodiversity Information Facility, using a data package titled “Brachiopoda collection of the Shirshov Institute of Oceanology, Laboratory of Ocean Benthic Fauna.” The Darwin Core structure connects individual records with shared biodiversity-information standards, while the public archive makes the data available in a machine-readable Darwin Core Archive format. The dataset also includes records for research vessel and cruise identifiers, station or field numbers, sampling protocols, locality descriptions, water bodies, countries, coordinates, depth values, taxonomic ranks, type status, specimen preparations, and associated media. This level of standardization allows records to be discovered and reused by wider communities, including those working far from the institute’s laboratory.
The practical impact extends well beyond the cataloguing of museum drawers. Brachiopods are stationary, long-lived filter feeders that occupy the seafloor and can be highly specific about environmental conditions, making their occurrence records useful in analyses of habitat, depth, and biogeography. The archive provides baseline data for taxonomy and phylogenetics, as well as for macroecological studies of global marine ecosystems. It can also support efforts to map where living brachiopod diversity has been documented, identify regions or depth layers that remain undersampled, and place new discoveries within a century of accumulated evidence. Because many deep-sea species were named from isolated samples, a connected record of type material, coordinates, and collection circumstances is especially valuable for testing whether older identifications remain valid. In an era of accelerating ocean research, the dataset offers both a historical reference and an invitation to discover what remains hidden below.
Subject of Research: Digitization of a century-long global brachiopod specimen collection
Article Title: Brachiopoda collection of the Shirshov Institute of Oceanology, Russian Academy of Sciences
Article References: Dudnik, Z. (2026). Brachiopoda collection of the Shirshov Institute of Oceanology, Russian Academy of Sciences. Biodiversity Data Journal, 14, Article e191347. https://doi.org/10.3897/bdj.14.e191347
Image Credits: AI Generated
Keywords: brachiopods, deep-sea biodiversity, museum collections, ocean biogeography, taxonomy, digitization, marine ecology, Darwin Core, Global Biodiversity Information Facility, Romanche Trench, Brachiopoda, collection
News Source: Violet Maxwell. (October 19, 2026). Ocean Time Capsule Reveals a Century of Brachiopod Diversity. Scienmag.
