There is robust morphological support for the placement of the zebra shark, the whale shark (Rhincodon typus), and the nurse sharks (Ginglymostoma cirratum, Nebrius ferrugineus, and Pseudoginglymostoma brevicaudatum) in a single clade. However, the interrelationships between these taxa are disputed by various authors.[6] Dingerkus (1986) suggested that the whale shark is the closest relative of the zebra shark, and proposed a single family encompassing all five species in the clade.[7] Compagno (1988) suggested affinity between this species and either Pseudoginglymostoma or a clade containing Rhincodon, Ginglymostoma, and Nebrius.[3] Goto (2001) placed the zebra shark as the sister group to a clade containing Rhincodon and Ginglymostoma.[6]