Shimakaze was a prototype, that got named as a member of a Kagerou-class while her design was completely different to her sisters, being classified as her own class. (Sort of what happened with Ayanami-class, who were a continuation of the naming from Isonami, the last of Fubuki-class; or Yuugumo-class as a continuation of the naming from Akigumo from the same Kagerou's)
