Released a new version of the abcimport shader that is compatible with mental ray 3.12 and mental ray for Maya 2015. It can be downloaded from this link. The package contains a version for Windows, Linux and Mac OS X, as well as the .mi file with the new shader declaration.

 

For more info: http://blog.mentalray.com/2015/02/19/new-version-of-alembic-import-shader/