The docs say:

All public methods of the RoboFile class will be treated as commands

and imply that the method name is used verbatim.

However, a method called task455MergeDevelop says:

  Command "task455MergeDevelop" is not defined.
 Do you want to run "task455:merge-develop" instead?  (yes/no) [no]:

The docs should explain this translation.

Also, is there a way to specify what the command name should be?