Volrath's Shapeshifter and Phyrexian Dreadnought

[Tog]

This came up when I was playing on MWS. There is a Volrath's Shapeshifter in play with a Dreadnought in the yard. I attempt to Shriekmaw the Volrath's Shapeshifter but my opponent was adamant about it being an artifact too therefore couldn't be destroyed by the Maw. Intuition tells me this isn't right but I'm no rules guru. Care to help?

~Tog

[Cait_Sith]

From the reminder text:

(Volrath's Shapeshifter has that card's name, mana cost, color, types, abilities, power and toughness.)

Emphasis mine.

It would be protected from Shriekmaw because Artifact is a type of Dreadnought and Volrath's copies types (so it would be an artifact creatures as well).