FIGURE 2.

Phylogeny of deuterostomes, indicating the points of origin of the characters discussed in this article. Most phylogenetic analyses place Deuterostomia as a monophyletic group (as depicted here), with Chordata and ambulacria as sister groups. However, some recent findings using large scale genetic databases claim that there is no evidence for Deuterostomia as a monophyletic group (Kapli et al., 2021). Hence the interrogation mark shown at this node. The main conclusions of this article are consistent with both views.