'Immaculate conception' mystery at aquarium

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An aquarium in Australia has had some unexpected births – in a tank that hasn't been occupied for more than four months.

The tank, at Reef HQ Aquarium in Townsville Queensland, had previously held an Upside-down jellyfish (Cassiopea xamachana), which had been removed from the main tank after it had been injured.

Unfortunately the jellyfish had died but four months later the tank was examined and found to contain over 200 Upside-down jellyfish polyps.

There is an added mystery too, as it doesn’t seem as though these can be clones.

Krystal Huff the Reef HQ aquarist is quoted in the Townsville Bulletin: "Jellyfish either produce sexually through reproduction or asexually through cloning. Jellyfish clone very easily, when some jellyfish are cut in half, you get two jellyfish. Since the parent jellyfish was injured its damaged tissue cells could have easily grown into other jellyfish."

These jellyfish have grown from polyps though, which you would usually only see as a result of sexual reproduction – and this jellyfish was in an isolation tank, making it all the more mysterious.
 
This species originates from the western Pacific and is often found in the shallow water in mud and sandflats around the Great Barrier Reef. The jellyfish will eventually grow to a diameter of around 20cm/8".

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