Calcisponges have a ParaHox gene and dynamic expression of dispersed NK homeobox genes.
A new study, published today in Nature, reports the analysis of new sponge genome sequences that reveal the presence of genes previously unknown from so early in animal evolution.This means that the earliest animal, living over 600 million years ago, was genetically more complex than previously appreciated.
http://www.st-andrews.ac.uk/news/archive/2014/title,250984,en.php
http://www.nature.com/nature/journal/v514/n7524/full/nature13881.html
http://www.nature.com/nature/journal/v514/n7524/full/514570a.html