Figure 1From: Lim homeobox genes in the Ctenophore Mnemiopsis leidyi: the evolution of neural cell type specificationPhylogenetic relationships of 'basal metazoa'. Phylogenetic relationships of early branching metazoan taxa, based on data from recent studies [45–47]. Non-definitive nervous systems refer to the lack of morphological and physiological data to confirm their existence.Back to article page