Bathynomus Giganteus: Terrifying Sea Beast Hauled Up by Jeremy A. Kaplan (FOXNews.com) National Geographic

A submarine exploring the ocean's depths recently returned with an unexpected visitor: a crablike critter called Bathynomus giganteus (commonly known as giant isopod) that has left many readers startled and horrified.

This giant isopod (a crustacean related to shrimps and crabs) represents one of about nine species of large isopods in the genus Bathynomus. They are thought to be abundant in cold, deep waters of the Atlantic and Pacific oceans.

Photo of Bathynomus giganteus courtesy of NOAA Vents Program

In a posting to social bookmarking site Reddit, a deep-sea technician detailed finding the Bathynomus giganteus, asking the site's readers to help identify what exactly the bizarre-looking creature was.
The post reads, "I work for a Sub-sea Survey Company, recently this beast came up attached to one of our ROVs. It measures a wee bit over 2.5 feet head to tail, and we expect it latched onto the ROV at roughly 8,500 feet depth.
"Unfortunately, the e-mail that these pictures were attached to came from a contractor, and the ship he was operating from (and therefore location) is unknown, so I can't tell you what part of the Earth this beast was living."

The pictures reveal Bathynomus giganteus to be a giant isopod, a large crustacean that dwells in deep Atlantic and Pacific waters. This particular creature is a deep-sea scavenger that feeds on dead whales, fish and squid.

The underside of a male giant isopod.

Photo courtesy of NOAA/OER.

Scientists have long remarked on the massive scale of Bathynomus giganteus.
C.R. McClain, writing about Bathynomus giganteus on ScienceBlogs, explained one theory for the size, that "deep-sea gigantism, for all crustaceans, is a consequence of larger cells sizes obtained under cold temperatures," citing a research paper from 1996.
He also speculated that "in crustaceans, bathymetric gigantism may also in part reflect decreases in temperature leading to longer lifespans and thus larger sizes in indeterminate growers."
Bathynomus Giganteus Post Inspires Curiosity, Horror
Responses to the original post ranged from the curious to the horrified.
One reader notes the connection between Bathynomus giganteus and a more familiar household pest: "The giant isopod is related to the "woodlouse"--turns out this is the common bug that I grew up calling a "roly poly"
or pillbug. Neat!"
Others were more disgusted with Bathynomus giganteus. "I remember watching some documentary (Blue Planet maybe?) with a time lapse of these things swarming a whale carcass. it was horrifying," writes one
reader.
Another reader saw nothing but dinner in the flesh of Bathynomus giganteus, writing "It could be because I really like seafood, but those isopods look tasty. Land bugs = ew! Sea bugs = mm mmm good."

Jeremy A. Kaplan is science and technology editor at FoxNews.com. A "frequent author and a technology nut," Jeremy worked previously at Ziff Davis Media, where he was executive editor of PC Magazine, launched several magazines, and co-hosted the Fastest Geek competition. He founded the GoodCleanTech blog, which was nominated for a 2007 Weblog award, a MIN Best of the Web award, and a finalist for a Jesse H. Neal National Business Journalism Award.

Read more of Jeremy's work on FOXNews/SciTech.