Krauze: the organisms we have chosen to represent invertebrates, like C. elegans and D. melanogaster, are simpler than the average invertebrate. And this means that we’re likely underestimating the complexity of the last common ancestor of animals (Metazoa). … Attempts to correct for this bias has found that the last common Metazoan ancestor was surprisingly complex, seemingly ‘overdesigned’ for its simple morphology.