Ok so today let's talk about tyranid weaponry. Specifically their close combat weapons. Since they never gain any bonus attacks, they simply have upgrades to their existing ones.... Ok, now what do we have:
Bone Swords- Sweet Jesus I'll take as many as i can get!
Really that is about it with them too.
Claws & Teeth - Well, yeah it's just attacks. nothing special to see here, move along
Crushing Claws - ok so i get an extra D3 attacks and strike at I of 1. so it's kind of an upgrade, but only take it if your are low initiative anyhow. otherwise you're wasting the attacks.
Lash Whips - Make anyone in base to base with you I1 with no way out of it.... yes please. Take that you eldar scum!
Rending Claws. While not as good as they were in 4th edition, they are still very good. lets Genestealers Auto-Pen rhinos with a rend, and kills lots of marines when you have lots of attacks. Great stuff on Raveners.
Scathing Tallons- While completely different than they used to be, they can be quite useful on SOME of your creatures. basically any with a WS of 5 or better can benefit from a Single pair. since you get to re-roll 50% of your misses most of the time.
So my advice? take lots of boneswords, preferably in pairs. LD on 3D6=Somebody is going to fail and die.
[EDIT TO ADD TO DISCUSSION] Now the question that a lot of people are asking is "Do Tyranid Biomorphs Stack? The simple answer is yes. since the tyranids never benefit from additional attacks and none of their weapons are "special weapons" the answer is yes. The biomorphs you add (at least IMO) are just that. upgrades. they're not "power weapon/plasma pistol" type combos. NOW, there are a few exceptions Bear with me as I explain this:
Boneswords (basically a force type weapon) you can take two or you can combine with a Lash Whip.
- This is a Special Melee weapon. You can't get bonus attacks so.... cool, 1 Special Weapon.
- Claws and Teed are your basic nid weapons..... so ok.
And that is it. Rending claws add rending to your attacks, (so not a special weapon)
Crusing claws add to your attack profile and modify your initiative (not a special weapon)
Lash Whips modify your opponent's Initiative(Not a special weapon)
Scything Tallons give you re-rolls (again, not a special weapon)
So you've got the option for 1 special weapon. No problems.