Question: are deuterostomes monophyletic or paraphyletic?
Answer: The deuterostomes are a monophyletic clade of bilaterians (Figure 1), and they are united in their form of developmental history. Specifically, the fate of the deuterostome blastopore is to become the anus (Figure 2). Also, the deuterostomes tend to develop by radial cleavage and form an endocoelic coelom.