South of the equator
There's no line there, but if a cartographer chose to draw one on his map or globe, then it would be the 'parallel' of 66° south latitude.
The line you are probably asking about is at 23.5 degrees South latitude, and it is called the Tropic of Capricorn.
It is known as the "equator".
the equator
Look for a colored line that goes straight north-south from the North Pole to the South Pole - latitudes. Longitudes are evenly spaced all the way around a globe. They will be equally spaced. The big one at the middle of the globe is the Equator. They have numbers on them. They start at 0 on the Equator.
No line of latitude is a north/south line. A move to the north or south is a change of latitude.
The latitude at the center of Wellington is about 41.3° South. That's south of the 40 degrees South line of Latitude.
That's the equator.
between 23.5 north and south are typically the tropics
'Zero latitude' is the definition of the equator.
That's the equator.
Hell.