Sometimes there is a small stinging spine (very rarely two) on the upper surface of the tail near the base.

The tail is short and stout, with a long, thick, serrated stinging spine.

Impaled his naked body with thousands of tiny stinging spines.

Uniquely within its family, it lacks a venomous stinging spine.

The tail also has no venomous stinging spine, unlike other members of the family.

The tail is longer than the disc and usually bears a single long, thin stinging spine on the upper surface.

In addition, the tail has alternating light and dark saddles past the stinging spine.

The tail is whip-like, much longer than the disc, and bears a stinging spine.

A single, serrated stinging spine is placed atop the tail, well behind the base.

On its upper surface is at least one, often two serrated stinging spines.