Girardia sphincter
Diagnostic description:
The presence of a sphincter at the base of the bursal canal makes G. sphincter different to all of its congeners.
Size:
Preserved specimens reach a length of 7-10 mm and a width of 1 mm.
Distribution:
It's only known from the type locality, a pool at Mt Barrow, northeastern Tasmania, Australia.
Ecology:
Freshwater.