Sub-species: Beasts of Prometheus and Resurrection

There are a number of creatures which seem to have spawned from the same DNA of the Xenomorph but would not be classed as one.

Hammerpede 
This creature first appeared in Prometheus and seemed to be some kind of larva worm that was exposed to the fluid from the ample chamber of the Jockey ship. Very like an earth cobra this little beast was aggressive and savage like a xeno. It shared the trait of acid blood like the xenomorph but also had the ability to regenerate itself from damage or attack regrowing its head after Fiefield cut it off.

The Decon

While man people call this a jockey xeno or a proto xeno however this creature didnt spawn from a facehugger but a human born creature that mutated in a massive facehugger like beast. The creature emerges fully formed from the jockey and cuts it way out with is crown blade very unlike an infant xeno. The jaws while like a xeno are more like a goblin shark which inner jaw expands the full range of the mouth. Also it has a placenta when its born which a xeno does not.

New Born

More of a gene splice gone wrong. When Ripley and the Queen DNA get mixed in the cloneing process and now the Queen has a human womb and gives birth to this monster. A loathsome creature with human eyes and features. This beast is like a toddler which dosent know its own power and with a creepy wide eyed wonder of a child this beast is the one of the few things in an otherwise letdown of a movie.