How does ribosomal RNA gene of sea urchin(Lytechinus variegatus) differ from that of Xenopus laevis?

Xenopus and sea urchins are in completely different phyla. The sea urchin is an Echinoderm and Xenopus is a vertebrate in the Chordate phylum. Being as distantly related as they are the rRNA is very different, as you would expect.