Overview
Agassiz’s Flapjack Octopus (Opisthoteuthis agassizii) is an enchanting, deep-dwelling cirrate cephalopod named after renowned Swiss-American naturalist Alexander Agassiz. Residing on dark bathyal and abyssal sea bottoms hundreds to thousands of meters down, this gelatinous ‘dumbo’ octopus is celebrated for its flattened, pancake-like silhouette, delicate ear-like swimming fins, and extensive web that links its short arms into an umbrella-like canopy.
Biology and Physical Characteristics
Characterized by a dorsoventrally compressed, soft gelatinous body, Opisthoteuthis agassizii lacks an internal ink sac and possesses reduced internal shell vestiges known as a U-shaped cartilage saddle. Its eight arms are connected almost to their tips by an expansive fleshy interbrachial web. Along the ventral surface of each arm runs a single row of suckers flanked on both sides by pairs of slender, finger-like sensory hairs called cirri. Two small, rounded fins sit above large, dark eyes adapted to detect bioluminescent flashes in perpetual darkness. Its skin ranges from translucent reddish-pink to deep coppery-orange.
Behavior and Ecology
Inhabiting depths from 500 to over 2,500 meters, Agassiz’s flapjack octopus utilizes two distinct locomotion methods: gently flapping its ear-like fins or pulsing its webbed umbrella to drift above the sediment. It frequently rests motionless directly upon soft seafloor ooze, flattening its arms like a pancake. When feeding, it hovers over the seabed and balloons its web downward in an ‘umbrella-pounce,’ trapping small benthic isopods, amphipods, and polychaetes which are manipulated into the mouth by the sensitive cirri. Females continuously produce and lay large, tough-shelled eggs on benthic rocks or gorgonians.
Conservation and Human Impact
Evaluated as Least Concern by the IUCN Red List due to its broad distribution across the Atlantic basin, Opisthoteuthis agassizii lives well beyond the reach of most human activities. Nonetheless, expanding deep-sea commercial bottom trawl fisheries in the eastern and western Atlantic occasionally catch cirrate octopuses as incidental bycatch, and potential future deep-seabed mineral mining poses concerns for abyssal sediment habitats.
Interesting Factoid
When resting on the seafloor, Agassiz’s Flapjack Octopus flattens its gelatinous arms into a completely flat disc resembling an orange pancake, blending into the abyssal silt to surprise passing amphipods.
Last updated: October 2026