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No, Those Aren't Penises: The NSFW Starfish Is Real

Nothing to see here but a whole lot of head.

author

Rachael Funnell

author

Rachael Funnell

Writer & Senior Digital Producer

Rachael is a writer and digital content producer at IFLScience with a Zoology degree from the University of Southampton, UK, and a nose for novelty animal stories.

Writer & Senior Digital Producer

Edited by Francesca Benson
author

Francesca Benson

Copy Editor and Staff Writer

Francesca Benson is a Copy Editor and Staff Writer with a MSci in Biochemistry from the University of Birmingham.

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Choriaster granulatus with 5 phallic "arms"

“No one cared who I was until they realized I looked like a cluster of penises,” – Choriaster granulatus, 2024.

Image credit: Harry Rosenthal via iNaturalist, CC BY-NC 4.0

You may recognize Choriaster granulatus from such subreddits as r/mildlypenis, r/intentionallypenis, and r/oddlyarousing. The starfish is famous for its penis-like “arms” – but what you’re really looking at is a whole lot of head.

C. granulatus, commonly known as the granulated sea star, is found across the Indo-Pacific. It enjoys warm waters and chilling on everything from rocky, rubbly surfaces to coastal coral reefs. Granulated sea stars sometimes ride solo, but they can also be found in gangs.

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They are carnivorous animals with mouths concealed beneath their doughy bodies, which have earned them the nickname "doughboy starfish" in honor of the Pillsbury Doughboy. It typically has the appearance of a classic five-armed sea star, but this can be deformed by parasitic limpets that are partial to clinging to their underside. 

choriaster granulated sea star
Admittedly, these bits don't help its case.
Image credit: Tonydiver via iNaturalist, CC BY-NC 4.0


Its five “arms” are a great demonstration of the five-fold symmetry we see in starfish, which have no clear head or tail. If you were ever wondering where to stick a hat on one, you might gamble on the center, but in truth, these animals are basically all head.

The staggering discovery was made in a 2023 study that used a combination of imaging and genetic techniques to create a 3D atlas of starfish gene expression. This included micro-CT scanning, which illustrated the skeleton, muscles, and digestive, nervous, and water vascular systems of a starfish, combined with RNA tomography and in situ hybridization – staining genetic material with fluorescent labels – to show which genes were being expressed and where.

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Their efforts revealed that the “head” of a starfish is, in fact, composed of headlike regions distributed in the center of its “body” and the center of each of its five limbs. Thus, what we think of as a starfish’s body is actually more like a head.

“It’s as if the sea star is completely missing a trunk, and is best described as just a head crawling along the seafloor,” said Laurent Formery, lead author of the new starfish study, in a statement. “It’s not at all what scientists have assumed about these animals.”

So before you go branding the granulated sea star a cluster of penises or the Pillsbury Doughboy, have a bit of respect and see it for the example of one of nature’s strangest heads that it truly is.


ARTICLE POSTED IN

natureNaturenatureanimals
  • tag
  • evolution,

  • animals,

  • starfish,

  • weird and wonderful

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