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New Species of Dumbo Octopus Identified Using 3-D Imaging Techniques

Techniques such as MRI and CT scans may allow researchers to identify and study rare sea specimens without the need for dissection

Traditionally, when taxonomists examine a potentially new species of octopus, they dissect them, an approach that is highly invasive and nearly destroys the specimen. (Alexander Ziegler)
smithsonianmag.com

Hidden in the depths of the ocean lives the peculiar Dumbo octopus. These octopuses have distinctive webbed tentacles that, when flared out, resemble an umbrella. Like their animated elephant namesake from Disney's Dumbo, the sea critters have fins above their heads that flap up and down as they steer and propel forward.

Now, using only minimally invasive image scanning techniques, researchers at the University of Bonn in Germany have now identified a new species of Dumbo octopus called, Grimpoteuthis imperator, reports David Nield for Science Alert. The study may potentially open up the world of taxonomy to new techniques that could help identify larger rare animal species and other specimens without destroying it during dissection. The paper was published in BMC Biology this month.

The Dumbo octopus genus is filled with rare species that are difficult to study because they reside in extreme depths of 13,100 feet below the ocean's surface. On sporadic occasions, they are seen up-close when caught in fishing nets.

While aboard a research vessel in the North Pacific Ocean, study co-author Alexander Ziegler, an evolutionary biologist at the University of Bonn in Germany, spotted a pink blob trapped in a steel net other researchers were using to hoist up rocks for study, reports Sarah DeWeerdt for Hakai. Upon closer look, Ziegler identified the pink blob as a Dumbo octopus from the fins on top of its head and immediately suspected it might be a new species.

Traditionally, when taxonomists examine a potentially new species of octopus, they dissect them, an approach that is highly invasive and nearly destroys the specimen. Taxonomists flip the octopus on its back, cut open the large area above its head that houses the octopuses' organs, remove all organs, and measure each one. To evaluate a cephalopod's beak, taxonomists will use chemicals to dissolve the tissues around the mouth, reports Hakai. Even if done delicately, the dissection process destroys the structural integrity of the specimen researchers can't go back and inspect it again if needed, explains Ziegler to Hakai.

Instead, Ziegler opted for a noninvasive approach. He first measured the octopus and photographed it. Then, he cut a small piece of tissue from the tip of one of its arms for DNA analysis and then preserved its body in formaldehyde. Once he was back in Germany, instead of dissecting the octopus, Ziegler imaged it using micro-computed tomography scanning (micro-CT) and magnetic resonance imaging (MRI) techniques to look at its organs, eyes, and mouth, Hakai reports.

From the imaging techniques, Ziegler and University of Bonn graduate student Christina Sagorny identified the shell and gill shape, the morphology of its digestive system, imaged the nervous system and sensory organs. In a first for the octopus species, they were even able to discern the shape of its heart from the images, reports Science Alert. Using the MRI and CT scan, the researchers also built an interactive 3-D model of a cephalopod beak.

The specimens' fin position, shell form, and arm length matched with the Grimpoteuthis, or Dumbo octopus genus. But the number of suckers along its tentacles, details of its shell, and the unique shape of its gills were unique enough to earn its own new species within the genus. The researchers named the new species, Grimpoteuthis imperator, or emperor Dumbo, after the underwater mountain range the Emperor Seamounts where researchers found the octopus, reports Bryan Lawver for Inverse.

Ziegler argues there would be no newly discovered species without the new technique of imaging the dumbo octopus. "I would not have dared to cut it up," Ziegler tells Hakai Magazine.

The research team hopes the new techniques can be used to study scarce specimens that are hard to come by without destroying them.

"The use of the 3-D imaging without dissection is a very useful concept," says Michael Vecchione, a cephalopod specialist at the Smithsonian Institution, not involved with the study to Hakai. "Even though the techniques have been around medically for a while, they're just now finding their way into research on animals like invertebrates."

About Elizabeth Gamillo
Elizabeth Gamillo

Elizabeth Gamillo is a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.

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