I've been having fun with this one for a week or something. It's based on several other's people's ideas with some of my own mingled in. Here's the prime inspiration;
For my own I dropped the idea of using the middle limbs for "eggsack-support". I thought the idea was great, but I prefered a set of talons to defend the head of the creature. The whole model is supposed to reinforce the idea that the head important to be kept intact; it's withdrawn in the body, heavily plated and has it's own talons for defense. It also has horns like a herbivore-like creature might have, like some old dinosaurs.
As can be seen it's made from an old Carnifex. I had 4 and that seems too much in their current codex incarnation. I'll keep 3, so one was left for this beast.
Some bits come from the Trygon, but these are rare.
To bulk out the Tervigon and warrant the 6 wounds, I added an extra armour plate to the front (subsequently requiring newly sculpted carapace tubes), which was sawn in two and enlarged.
Hope you like it!