Massive White Jellyfish

[Potestas]

Article is here that I stumbled across: Scuba diver Christian Hauser encounters a massive jellyfish while diving in Mexico  | Daily Mail Online

Now I was naturally curious about what kind of jellyfish this was. It was labeled a “white jellyfish” but upon a google search I couldn’t find a specific jelly fish species known as a “white jellyfish”.

I found links to the White Spotted Jellyfish and the Rounded Bell Jellyfish but neither seem to really match with the beautiful jellyfish from the photo in the article:

So I looked some more and I found the Lion’s Mane Jellyfish Lion's mane jellyfish - Wikipedia

However this type of jellyfish (Lion’s Mane) is found in colder deeper water and has been found in Australia, NZ and then much colder places. The jellyfish in the original article was found at a depth of 50 ft off the coast of Mexico.

Does anyone have any idea what type of jellyfish this is and any information about it, its sting, etc?

[wevets]

Definitely not a lion’s mane jelly - the lion’s mane has a distinctive 8-lobed symmetry to its bell, and the jelly in the video does not have that, it has more of a flat, smooth bell. No idea what kind of jelly it actually is, but you can rule out the lion’s mane.

[DrDeth]

Stygiomedusa gigantea. is my guess.

[wevets]

While I suppose that’s possible, but could you elaborate a little?

Here’s a video of Stygliomedusa gigantea on the other side of Mexico from the OP’s… it really doesn’t look all that similar - admittedly, coloration and size are not good indicators of identity in the jellies - variation within species is really broad there. The thing that makes me skeptical is the morphology - S. gigantea has those huge paddle arms, which don’t show up in the OP’s video.

[sitchensis]

That looks like a big but fairly normal sized jellyfish to me. One of pictures makes it look huge because of the scale.

[astro]

5 Types of Jellies in the Gulf of Mexico — Sanibel Sea School

Atlantic Sea Nettle - Chrysaora quinquecirrha

Sea nettles possess several long tentacles and long, trailing oral arms. What’s interesting about these jellies is that their colors vary depending on salinity levels and therefore may appear transparant or white when found in brackish waters on the bayside of Sanibel. When found in the saltier waters of the Gulf, red and brown streaks radiate from the center of the bell.

[DrDeth]

@wevets

While I suppose that’s possible, but could you elaborate a little?

Here’s a video of Stygliomedusa gigantea on the other side of Mexico from the OP’s… it really doesn’t look all that similar - admittedly, coloration and size are not good indicators of identity in the jellies - variation within species is really broad there. The thing that makes me skeptical is the morphology - S. gigantea has those huge paddle arms, which don’t show up in the OP’s video.

You make a good point, but Stygiomedusa gigantea does vary a lot, is the right size and is found in that location. It is also quite rare.

sitchensis might be right also.

[wevets]

@sitchensis

That looks like a big but fairly normal sized jellyfish to me. One of pictures makes it look huge because of the scale.

At 0:25 in the linked video, there’s good perspective where the jelly is almost as far from the camera as the diver in the background, which I’m guessing makes the bell of this jelly about 1.5-2.5 ft across and the arms/tentacles about 3-5 ft long - it’s definitely filmed so that it appears larger than the divers in the background - someone could be forgiven for thinking it was 4-5 ft across and 6-8 ft long without accounting for perspective, but the jelly itself is in the foreground.

@astro

5 Types of Jellies in the Gulf of Mexico — Sanibel Sea School

There is an equivalent Pacific Sea Nettle which could be near Puerto Vallarta where the OP video was taken, but this is not that species - Pacific sea nettles have dark fringing tentacles, and their bells are more rounded than the jelly in the OP.