Three of a Kind: What?? They're all the SAME??

An interesting fact!

DID YOU KNOW: That THIS: Colobocentrotus atratus

THIS... Red Pencil Urchin (Heterocentrotus mammillatus)

AND THIS...

ALL actually all members of the SAME Family!! (i.e., the same group)-the ECHINOMETRIDAE.  Here are all their tests (their skeletons for comparison).  Note how these all have that oblong, almost bilateral shape to them.

Colobocentrotus atratus

https://hu.wikipedia.org/wiki/Colobocentrotus_atratus#/media/File:Colobocentrotus_atratus_MHNT_Bali_Test.jpg

Heterocentrotus mammillatus

https://commons.wikimedia.org/wiki/File:Heterocentrotus_mamillatus_test_aboral.JPG

Echinometra mathaei


Its all about the spines! They all vary with habitat! Evolution is a wonderous thing!