(ORDO NEWS) — Scientists have identified an anemone whose fossils have been mistaken for a jellyfish for many years. It is reported by the University of Illinois.
The studied remains come from the Mason Creek deposit in the United States. The ancient river delta created ideal conditions for preserving the soft tissues of many invertebrates by burying them in muddy sediments.
The most common fossil in Mason Creek is the so-called “drop”. Such drops were so common and often nondescript that many were thrown away or sold for a few dollars at local flea markets.
In the 1970s and 80s, scientists came to the conclusion that they were jellyfish and named them Essexella asherae.
These jellyfish allegedly had a unique feature that no other living jellyfish has – a rigid “curtain” that hung from the umbrella-shaped “bell” – the top of the jellyfish – like a skirt that covered their tentacles, which explained their barrel-shaped shape.
Now Roy Plotnick and his colleagues have done more research and concluded that the identification of these animals as jellyfish was a mistake.
They mentally turned the find upside down, after which everything fell into place: it looked like an anemone buried in the seabed.
The “bell” was actually an enlarged muscular leg hooked to the bottom. The barrel-shaped body of the sea anemone became a rigid “veil”.
“Although most of these fossils are preserved as decaying patches that look like a piece of used chewing gum on the sidewalk, some specimens are so perfectly preserved that we can even see the muscles that anemones used to bend and contract their bodies,” scientists explain the problem.
The researchers explain that the large external diversity of Essexella specimens was due to the varying length of time that dead anemones were on the seafloor before being buried in the silt.
At the same time, this sea anemone was not a predator, unlike many modern species, but a scavenger.
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