Do you have Android.com - Android File Transfer
installed on your Mac?
Which revision of OS X are you running?
My bet is that the phone has sensed data lines connected, could not find an MTP interface (as provided by Android File Transfer) and then ran home to momma with a usb debugging setup.
MTP - mass transport protocol - a Windows protocol that you requires that add-on for a Mac.
Due to later OS X updates, AFT now doesn't see every Android on every Mac, but it's your best bet.