Tiny star on film

Author
by Blair
Publish date
3 July 2011
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Comments (6)

In 2007, Museum Victoria research scientists described the world's tiniest starfish, the Paddle-spined Seastar. Here are three of them under the microscope last week, filmed by Ben Healley.

 

Like all starfish, these animals are powered by many legs called tube feet. Each has a sucker on the tip which is how they crawl around and hang upside down under rocks. On the video they appear transparent so are difficult to see moving out from underneath each arm. They stick to the glass and drag the animal across the surface.

They don’t have eyes but they do have eyespots. You can also see these on the video. They are the dark patches at the tip of each arm, on top of the animal. Detecting light and dark, they help the animal tell if it is under a ledge or on top of it, or whether something large, like a possible predator, is passing overhead.

Interestingly, the individual pictured in reports when this species was discovered has five legs, not six. According to MV curator Dr Tim O'Hara, "it’s typical for this species to have six arms but every now and then, you’ll get an uneven split during reproduction and end up with a five-armed individual.”

Links:

MV News: Tiny star

Comments (6)

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Johnny 13 July, 2011 09:44
Great blog Blair! You're a star!!
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Blair 6 July, 2011 10:15
And Cilla, it does sound horrific but they're so expert at it that I doubt it hurts at all. Their bodies are lined with many stem cells and these can be triggered to regrow the different body parts. Why some animals can reapir their bodies and others cannot inspires scientists to investigate how nervous systems regenerate.
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Blair 5 July, 2011 12:48
Glad you liked it Shari and Emily. The footage was captured by Ben Healley in our filming studio. We're pretty sure this is the first live footage of this small starfish, so I agree it's an amazing clip!
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Emily 5 July, 2011 04:30
Great footage here! And good detail in the voice-over, I just gave a presentation on reproduction, this would have been great to have with the powerpoint! And Cilla; this sea star is fissiparous ... like many small echinoderms it reproduces using specialised asexual methods ... In this case fissiparity. It can split itself in half then regenerate the missing parts! Quite amazing (: Well done Blair!!!
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Shari 4 July, 2011 18:53
I was waiting to see a video of these guys! Lovely work Blair :)
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Cilla 4 July, 2011 16:59
Great! I really like the footage... How does it 'chop itself in half' though? Sounds horrific!
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