What defining morphological feature secures the Zebra Shark's placement within Family Stegomatidae?

Five gill slits, with the fourth and fifth sometimes partially fused

The grouping of sharks into the Family Stegomatidae relies on shared defining morphological features, one of which is the count and structure of the gill slits. Specifically, members of this family are characterized by having five gill slits, with a notable feature being that the fourth and fifth slits frequently show a partial fusion. Other distinguishing characteristics that secure the Zebra Shark's placement within this family include the presence of prominent longitudinal ridges along the body, although these structures tend to diminish or disappear entirely as the shark progresses into its adult stage. These features, in conjunction with fin structure, solidify its standing within this specific family within the Carpet Shark order.