Monstrous sea anemone from 2500m


Here’s an old favorite from April 2006.

An enormous sea anemone from 2500m depth on the East Pacific Rise was reported in in the journal Marine Biology. The monstrous actiniarian Boloceroides daphneae is abundant on boulders, cliffs, and rocky outcrops near hydrothermal vent sites but not on them, writes author Marymegan Daly from Ohio State University. The largest living specimen she found had a column diameter of 1m, a tentacle crown of 2m diameter, and tentacles trailing an estimated 3m and more. That’s just downright dangerous. B. daphneae’s closest living relative is the comparatively diminutive Cerianthid anemone found in warmer coastal waters.

The new species has been known since 1990, but it was tough to collect, and it provides a good example of commonly encountered but largely unstudied species in the deep sea environment. According to Daly, the eggs of B. daphneae are yolky, and should therefore be long lived. Theoretically, they should also be capable of fairly broad dispersal on deep ocean currents, maybe even caught in a hydrothermal updraft to be cast even more widely. This would account for their broad distribution. Ten or more giant anemones can be seen in a ‘typical’ eight hour submersible research dive.

Here is a link to more.

Image by Stephane Hourdez/IFREMER.

6 Replies to “Monstrous sea anemone from 2500m”

  1. I was on that 2003 EPR cruise with Meg where the specimens studied were collected. It was an utter mess. It shed all its tentacles so it was just a column and several long gooey tentacles in the temperature sealed boxes. One of my jobs on the ship was compiling the video so I got to see almost every single tape produced on that cruise. It is a very elegant creature, with its long (1-2 meters!) tentacles waving in the slow deep sea currents, almost saying hello to us as we passed by it in Alvin.

    It was wrongly identified for at least more than 15 years as a Cerianthus sp. in the literature and guides. Which is marvelous that after so many years and documentation that no one ever stopped to make a grab! Apparently the French did do this in the Atlantic but it remained in a museum.

  2. Amazing. Can you forward a copy of the video? I would love to see the living animal in all its tentacular glory.

  3. All the video is at the Field Museum and Wood’s Hole. I only have pictures from that cruise.

    Even on shallow reefs and the intertidal some anemones get pretty big. There are some Anthopleura on the rocky coasts from British Colombia (Canada eh) to northern CA that could swallow a small yappy dog.

    I don’t think there were any hints to what it eats in the paper, but as a typical passive predator it probably waits for any passerby’s, like crustaceans or small fish, to immobilize and eat.

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