Nature School Game Contact Blog Project Noah Facebook Project Noah Twitter

A global citizen science platform
to discover, share and identify wildlife

Join Project Noah!
nature school apple icon

Nature School For Teachers - Fall 2020 Launch! visit nature school

Heart sea urchin

Maretia planulata


The body of hear urchins is shaped a bit like a Valentine heart lying on its back, with the indented end pointing forward. The mouth is toward that end, on the bottom of the urchin below the indentation, so that the urchin has a definite front end, with the anus at the back. Because these displacements destroy the nice five-part symmetry seen in “regular” urchins, these are logically known as “irregular” echinoids.


Lives buried in the sand. At night, a species in the genus Maretia emerges from the sand where it buries itself during the day, and marches in comical herds across the bottom in search of food. With the long trailing spines and amazingly rapid motion, it’s not difficult to see how these became known as sea mice.


Info extracted from:

Species ID Suggestions

Sign in to suggest organism ID


The MnMs
The MnMs 6 years ago

Thanks, Chief! :-)

Interesting fndi!

Maria dB
Maria dB 7 years ago

nice spotting!

The MnMs
Spotted by
The MnMs

Negros Oriental, Philippines

Spotted on Oct 3, 2012
Submitted on Nov 2, 2012

Related Spottings

Heart Urchin fossil Heart Sea Urchin Sea Potato or Heart Urchin

Nearby Spottings

Horned bannerfish Dragon wrasse juvenile Dwarf hawkfish Map puffer
Noah Guardians
Noah Sponsors