Jellies Down Deep
Welcome to the Subfamily
Almost from the moment George Matsumoto of the Monterey Bay Aquarium Research Institute first saw “Big Red,” he knew he was looking at a new species of jellyfish. It looked just plain bizarre: bulbous, dusky red, and huge, nearly one meter (about three feet) in diameter, with several fleshy arms instead of tentacles, like a balloon with greedy fingers. When Matsumoto and his coauthors, Kevin Raskoff of California State University and Dhugal Lindsay of the Japan Marine Science and Technology Center, described it in a scientific paper in 2003, they gave it a more official name: Tiburonia granrojo.
“Because we’ve spent so much time in the field and we’ve seen so many pictures, whenever we see something that doesn’t match up we get this feeling that it’s a new species,” Matsumoto says, “which of course generates a lot of excitement and enthusiasm.”
These are busy times for jelly discoverers. The use of submersible vehicles has enabled scientists to explore the world of jellies in depth; new creatures are constantly appearing. In February 2004, Raskoff and Matsumoto announced the discovery of yet another deep-sea jelly, Stellamedusa ventana, a tentacleless organism they’ve affectionately named “Bumpy” for the many warty lumps on its softball-size body.
The best-known groups of jellies are the jellyfish and comb jellies. Jellyfish belong to the class Scyphozoa within the larger phylum Cnidaria. All cnidarians possess stinging cells called nematocysts. The phylum Cnidaria also include the classes Hydrozoa, Anthozoa (corals and sea anemones), and Cubozoa (sea wasps and box jellies). Comb jellies belong to an entirely separate phylum, Ctenophora. The ctenophores gather food and ensnare prey with sticky cells rather than stinging cells. Unlike cnidarians, which propel themselves with rhythmic contractions of their bells, comb jellies paddle through the water with tiny oarlike cilia on the outsides of their bodies. Though many jellyfish and comb jellies look outwardly similar, the two groups are evolutionarily distinct. Only recently have scientists successfully described Cnidaria and Ctenophora as distinct phyla. Due to similarities in appearance, the two together had previously been known as coelenterates.
Classifying a new jelly species is a difficult process. “Every time I do it, it’s a lot of work, but it’s also very rewarding,” Matsumoto says. A scientist must have a good understanding of what has already been described, and must do a very thorough review of the existing literature in order to feel confident that the “new” species is in fact new to science and not just new to the scientist. “As with anything, you can’t know what’s new until you’ve spent some time looking at what’s already out there,” Raskoff says.
“Big Red” was first spotted on video during a submersible dive in 1993. In 1998, after several more sightings, Matsumoto was called in to identify it. He and Raskoff went back and pored over years of video footage to learn more about the animal’s typical size and geographic range. They also closely examined its anatomy for comparison with other known species. Big Red is unusual in that, unlike most jellyfish, it has no tentacles, only several fleshy arms to capture food. It is so different from other jellies that researchers ultimately assigned it to its own subfamily, Tiburoniinae.
