bulldogskjell
Macandrevia cranium
The bulldogskjell (Macandrevia cranium) is a distinctive deep-sea brachiopod characterized by its robust, skull-like shell with pronounced ridges and a broad, flattened profile reminiscent of a bulldog's face. This sessile filter-feeder plays a crucial role in benthic ecosystems by processing organic matter from the water column and providing hard substrate for other marine organisms to colonize.
19
Countries
Photo: iNaturalist: (c) Amphibol, some rights reserved (CC BY-SA)
Taxonomy & Classification
Kingdom
Animalia
Phylum
Brachiopoda
Class
Rhynchonellata
Order
Terebratulida
Family
Zeilleriidae
Genus
Macandrevia
bulldogskjell belongs to the family Zeilleriidae, order Terebratulida, within the Rhynchonellata class.
Species Profile
The bulldogskjell (Macandrevia cranium) is a distinctive deep-sea brachiopod characterized by its robust, skull-like shell with pronounced ridges and a broad, flattened profile reminiscent of a bulldog's face. This sessile filter-feeder plays a crucial role in benthic ecosystems by processing organic matter from the water column and providing hard substrate for other marine organisms to colonize.
The bulldogskjell (Macandrevia cranium) faces severe population decline primarily due to deep-sea trawling activities that destroy its fragile cold-water coral reef habitat. Climate change-induced ocean acidification and warming temperatures further threaten the species by degrading the calcium carbonate structures it depends on for survival. The species' extremely limited range and slow reproductive rate make recovery particularly challenging.
Key Facts
Habitat & Distribution
Macandrevia cranium inhabits cold, deep continental shelf waters between 200-800 meters depth, typically anchoring to rocky outcrops and stable sediment areas with strong bottom currents. The species requires low-temperature environments with high dissolved oxygen levels and specific calcium carbonate saturation conditions found along northern Atlantic and Pacific continental margins.
Threats
IUCN Red List: Critically Endangered
The bulldogskjell (Macandrevia cranium) faces severe population decline primarily due to deep-sea trawling activities that destroy its fragile cold-water coral reef habitat. Climate change-induced ocean acidification and warming temperatures further threaten the species by degrading the calcium carbonate structures it depends on for survival. The species' extremely limited range and slow reproductive rate make recovery particularly challenging.
Climate change and ocean warming
Deep-sea bottom trawling
Habitat destruction from fishing gear
Ocean acidification
Limited dispersal ability and small population size
Found in 19 Countries
Community Sightings
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Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
This page: SpeciesRadar (2025). bulldogskjell (Macandrevia cranium). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/bulldogskjell