Megaloceros have 9 physical mutations, 4 of them are Mane Mutations, 4 are Tail Mutations and the last one is the Fangs Mutation.
While it is possible to combine a Mane and a Tail Mutation, it is not possible to have two or more Mane / Tail Mutations at a time. There are three exceptions however: Bearded, Markhor and Draft, which may be combined with any other Mane Mutation.

Standard Mane and Tail:

Mane – Wispy:

Mane – Razor:

Mane – Wapiti:

Mane – Bearded:

Mane – Draft:

Mane – Mudstone:

Mudstone can only be passed down from Enlil or other beasts having this Mutation. It cannot be chosen for Semi-Customs.
 

Tail – Bobtail:

Tail – Curly:

Tail – Long:

Tail – Wing:

Misc – Fangs: