Uploaded March 2026 | Updated September 2026, 3 weeks ago
Dr. Chris Mah specializes in echinoderms, which are any animals of the phylum Echinodermata, including starfish, brittle stars, sea urchins, sand dollars, and sea pigs like this sea-thru, groovy swimmer. The animal belongs to the family Elpidiidae in the genus Peniagone. He says they can swim when they wish, but prefer the seafloor.
Sea pigs spend most of their time sifting through sediments, dining on decaying organic matter, making them essential members of the seafloor cleanup crew.
Not one to focus on only one of the echinoderms in the frame, Mah says the urchin is an Echinothurioid, commonly called a pancake or tam o’shanter urchin. He adds that they have cute little "booties" on their spines around the bottom fringe, for "walking" on soft bottom sediments. They are related to shallow-water fire urchins, which are venomous and can deliver an unpleasant sting when handled.
The footage was collected during the #ArgentinianDeepSeeps expedition at 2864 meters — almost two miles — beneath the surface. Credit: ROV SuBastian / Schmidt Ocean Institute
Dr. Chris Mah specializes in echinoderms, which are any animals of the phylum Echinodermata, including starfish, brittle stars, sea urchins, sand dollars, and sea pigs like this sea-thru, groovy swimmer. The animal belongs to the family Elpidiidae in the genus Peniagone. He says they can swim when they wish, but prefer the seafloor.
Sea pigs spend most of their time sifting through sediments, dining on decaying organic matter, making them essential members of the seafloor cleanup crew.
Not one to focus on only one of the echinoderms in the frame, Mah says the urchin is an Echinothurioid, commonly called a pancake or tam o’shanter urchin. He adds that they have cute little "booties" on their spines around the bottom fringe, for "walking" on soft bottom sediments. They are related to shallow-water fire urchins, which are venomous and can deliver an unpleasant sting when handled.
The footage was collected during the #ArgentinianDeepSeeps expedition at 2864 meters — almost two miles — beneath the surface. Credit: ROV SuBastian / Schmidt Ocean Institute
