When you create a new site collection in SharePoint 2013 ,the following groups are created by default.
Approvers
Designers
SharePoint Group Design
Hierarchy Managers
Joyfulsite Members
Joyfulsite Owners
Joyfulsite Visitors
Restricted Readers
Translation Managers
The corresponding permission levels are
Approve
Design
Manage Hierarchy
Contribute
Full Control
Read
Restricted Read
Restricted Interface for Translation.
Here Joyful is my site collection name and kindly don't get confused with that.!!