Atlantic sea nettle jellyfish are two distinct species

Jellyfish are one of the most enigmatic and alien sea creatures on the planet. They range from the highly poisonous Irukandji jellyfish to the giant lion’s mane jellyfish, which is one of the longest recorded creatures with a length of 121 feet.

Not much is known about the behavior of these umbrella-shaped gelatinous spots that can be seen pulsing in ocean waters around the world at various depths.

University of Delaware professor Patrick Gaffney and former student Keith Bayha, an associate researcher at the Smithsonian National Museum of Natural History, have made a startling discovery that could change the classification of jellyfish forever.

The study they published in the PeerJ journal determined that a common sea nettle jellyfish, which was considered a single species, is in fact two separate species.

Atlantic sea nettle is one of the most common and well-known jellyfish on the east coast of the United States, especially in Chesapeake Bay and Rehoboth Bay, where they commonly bite swimmers. In large numbers. The species was discovered 175 years ago, and since then it has been speculated to be a single species of jellyfish. Using a series of DNA sequencing techniques, the study concluded that they were in fact two distinct jellyfish species, those found in the oceans are different from those found at the edge of the bay.

“Before DNA came along, people in museums would look at organisms and count thorns and silks, measure things and sort organisms based on their physical characteristics in order to identify species,” Gaffney said. in a press release. Press release. “In the case of this jellyfish, known for centuries, Keith discovered through DNA sequencing that there were actually two groups.”

The study found that the stinging nettle jellyfish is larger and has about 40 percent more tentacles than its bay counterpart.

The sea nettle also has a larger bell, the upper part of the aquatic animal, while the tentacles are shorter than those of the bay nettle species, the statement said.

The team collected jellyfish off the Delaware coast near Cape Henlopen, as well as a wide range of samples from Norway and Brazil. They also studied Smithsonian museum specimens.

Genetic testing of the samples revealed differences in some of the sea nettle jellyfish. Bayha confirmed that there were in fact two distinct species: an oceanic species (Chrysaora quinquecirrha, “sea nettle”) and a species of sea nettle. bay (Chrysaora chesapeakei, “bay nettle”) by comparing DNA data to physical measurements of each species. and using statistical modeling to determine the morphology to separate species.

“When you go back and pay close attention, you start counting the number of cells and stinging types, you see subtle differences that match the DNA,” Gaffney said in the release. “In many cases, when we plotted the data, the graphs looked entirely different with no overlap, reaffirming that they were two species.”

The team says bay nettle is found in less salty waters called estuaries, such as the Chesapeake Bay. There is a daily jellyfish forecast by the National Oceanic and Atmospheric Administration for Chesapeake Bay, where jellyfish blooms can sometimes become a nuisance.

The team believe the inability to understand the jellyfish flowers here is due to the fact that we didn’t consider two separate species.

Interestingly, the new research has shown that bay nettle appears to be closely related to jellyfish found in coastal areas of Ireland, Argentina and Africa.

“It’s not that I did something so different, it’s just that no one else has watched for a very long time,” Bayha said. “Jellyfish are something people don’t pay attention to because they are fleeting. They come and go, are difficult to study, and they don’t have hard parts like seashells washing up on the shore.”

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