 The closest relative of the smalleye hammerhead appears to be the scoophead ("S. media"), and the two of them in turn form a clade with the sister species pair of the scalloped bonnethead ("S. corona") and the bonnethead ("S. tiburo").One of the smaller members of its family, the smalleye hammerhead can reach a length of , though is more typical, and a weight of .The body is streamlined and fairly slender.