Nice Deer! To make the call Blacktail/Muley, check the tail...black on the tip only, or on just the half towards the tip, is a Mule Deer. Black on the whole length of the tail is a Blacktail.

There is no scientific way to use the antlers as a way to positively identify Blacktail from Muley.
You can however, use antlers to differentiate between Whitetails and Blacktail/Muley....tines from a main beam, with no forks in the tines above the main beam (with the exception of the eyeguards!)indicate Whitetail. Antlers that fork before forming one main beam indicate Blacktail/Muley.

I thought your deer looked a lot like a Whitetail until I saw the fork in the tine near your right hand.

Regardless of the species,