Weird and Wonderful: This spectacular deep-sea siphonophore is a sight to see

We’ve discovered a rainbow of siphonophores in the depths of Monterey Bay and beyond, like this stunningly scarlet species, Marrus claudanielis, described by MBARI researchers and their collaborators in 2005. The scientific name honors the husband-and-wife team Claude and Danièle Carré for their contributions to our understanding of siphonophore biology.

Siphonophores (pronounced “sigh-fawn-oh-fours”) are colonial creatures made up of specialized segments that work together as one. Scientists have described some 175 siphonophore species. Most follow a similar body plan—a gas-filled float provides buoyancy, swimming bells propel the colony, and a central stem bears specialized parts for feeding, defense, and reproduction. Siphonophores are some of the longest animals in the world, with the giant siphonophore estimated to get up to 40 meters (132 feet) long, but only as big around as a broomstick. They capture prey with a curtain of stinging cells, allowing them to consume organisms much beefier than they are.

Like most other siphonophores, Marrus claudanielis lives far from the seafloor, calling the endless expanse of open sea and midwater their home. They are ethereal and delicate organisms, readily jettisoning body parts when threatened. The cast-off swimming bells are bioluminescent and likely function to confuse predators, but this trait also makes them particularly challenging to study. Thankfully, MBARI’s remotely operated vehicles (ROVs) give scientists the opportunity to get a close-up look at deep-sea siphonophores without damaging them. Our skilled pilots carefully maneuver the ROV to record stunning video of these delicate drifters. These observations complement specimens we gingerly collect with samplers on the submersible.

MBARI researchers and collaborators described Marrus claudanielis from specimens collected by ROVs off California and New Jersey. With observations off both coasts of North America, this species is likely widely distributed, but has simply eluded scientists. Although the deep sea is the largest environment on Earth, we’ve only explored a miniscule fraction of these midnight waters. Who knows what other fascinating discoveries linger in the darkness waiting to be found?
Scientific name: Marrus claudanielis (Dunn et al., 2005)
Size: Total length about 30 centimeters (12 inches)
Depth: 500–1,500 meters (1,640–4,920 feet)
Editor: Ted Blanco
Writer: Megan Bassett
Production team: Kyra Schlining, Susan von Thun, Nancy Jacobsen Stout

Learn more:
Creature feature: https://www.mbari.org/products/creatu...
The fish-eating siphonophore Erenna: https://youtu.be/Jp2qV4tI3sE

There’s no such thing as a jellyfish: https://youtu.be/3HzFiQFFQYw
Diet secrets of the rich and fathomous: https://youtu.be/TbGtPGFXEVc

Find more Weird and Wonderful deep-sea animals on our Creature feature: mbari.co/34hlCzV

Reference:
Dunn, C. W.; Pugh, P. R.; Haddock, S. H. D. (2005). Marrus claudanielis, a new species of deep-sea physonect siphonophore (Siphonophora, Physonectae). Bulletin of Marine Science. 76 (3): 699-714.