Finding all available styles defined by android platform themes

In several android styling tutorials parent style elements are used that i can not find in the android.R.style.* styles (http://developer.android.com/reference/android/R.style.html).

A few examples are from the http://android-developers.blogspot.com/2011/04/customizing-action-bar.html action bar article. Nick uses parent styles like:

<style name="MyDropDownNav" parent="android:style/Widget.Holo.Light.Spinner.DropDown.ActionBar">
...
</style>

or

<style name="MyActionBarTabStyle" parent="android:style/Widget.Holo.Light.ActionBarView_TabView">
...
</style>

Where do these parent styles come from? Is it possible to list all available parent styles?

Thanks.