rumeur tyty

"The Dominar embodies Tyranid Hive Mind completely. Within its shadow, lesser creatures bow in servitude, and larger Tyranids find greater access to the warp. It's armored shell protects it from the most powerful weaponry. Any enemy foolish enough to close with it will find no mercy, as it's claws and teeth rip through flesh and armor plating with ease, and within its massive body lie all manner of symbiotic organisms willing to defend their host.

The Karkanos is a lumbering, living fortress. Upon it's back, smaller Tyranids will gather for protection, waiting for the opportune moment to strike at their foes. Bristling with weapons, it can decimate foes as they close, while it's passengers target other enemies.

This multi-part plastic boxed set contains 84 components with which to build one Tyranid Dominar or one Karkanos. This kit contains all the weapon options available to the either creature including cluster spines, heavy venom cannons, brain leech devourers, and acid spray. This kit contains one Large Oval base. It is supplied unpainted and requires assembly - we recommend using Citadel Plastic Glue and Citadel Paints."

"The dominar has a 18" synapse range and Shadow in the Warp range, and increases the psyker level of all Tyranid Psykers within 6" by 1 level. Also has It will Not Die, psychic Monstrosity, IC(c) and can take most Tyranid Biomorphs. It's bigger than the Tyrranofex model, wider with a taller stance, huge head with a massive brain under a wide plate, large mouth like the trygons. It has three rows of vents along the back plates, but the back plates come up behind the head like a turtle, offering protection."

" the Karkanos looks like a crab. It has a wide flat body, the back plate is sunk in and has a ridge around the outer edges. It's front set of arms can hold a few weapon options like venom cannons or devourers or can take claws or talons. Transport capacity is identical to the spore, but it cannot carry MCs. It is a dedicated transport option for the walking troops: warriors, Genestealers, hormigaunts, Termagants. Open top. Has special rules to handle being a MC and transport...not a vehicle. It's probably one of the most expensive dedicated transports in the game. Can be taken in heavy section solo."

via a strong source here on Faeit 212 from back in August
Tyranids, at least at current can ally with themselves essentially.
They have the standard:
2 HQ
6 Troops
3 Elites
3 Fast Attack
3 Heavy Support

And can take an optional

1 HQ
2 Troops (not minimum 1, up to 2, but instead MUST take 2 and then...)

And if they do, it unlocks
1 Elite
1 Fast Attack
1 Heavy Support.

Only an HQ from the core can be warlord.

Then the diversity comes into play.

Hive Fleets now have different rules (think chapter tactics). Your secondary brood can be from a different hive fleet. Not representing two fleets working together, just similar evolutionary strains.

There are also army wide FoC changes based on your Hive Tyrant. Wings give you the option to take Gargoyles as your compulsory troops (so max 2) for instance.  Bonded carapace let's you take Carnifex's as elites as well as heavy support (but can't be more than a certain number of points, so they end up kinda baby).

They have some really cool adaptations for skyfire.

Warriors can be purchased as sergeant style upgrades for gaunts and gargoyles. They get the biomorphs of the brood and are not attached like wolf guard.

Tyrannofex will see a points decrease.

Pyrovore will see torrent.

Ranged biomorphs contribute to a model's close combat.
Melée biomorphs enhance a model's ranges attacks.
You take some biomorphs that affect both, like +1 str to both.
But having a gun makes melée better and having melée weapons improves your guns. There's some new synergy there. Mostly for big bugs.

Psychic ability is a lot worse than what it is now, but it'd be difficult to explain and just upset people who don't have the whole picture.

via BoLS 9-5-2013

   Karkinos: all you zodiac lovers will appreciate the reference. It is not known what form this Classical Greek monster will take in the new Tyranid codex, only that it is coming. Here is what else is on the way:


   Monstrous Creature Broods may not deploy in multiple Mycetic Spores. ~YIKES!!!

   HQ Trygon option.

   Parasite is now a Shrike upgrade character, and moves out of the HQ section.

   Tyranid Prime can now be purchased in Warrior, Shrike or Ravener forms.

   Many classic biomorphs have returned as upgrade options for most units.

   Many units can now run twice or run-assault. ~ nice countpoint to Battle Focus

   New unit that is static but extends synapse range. Can take some weapons and has cc ability if attacked.

   5 new units in the Tyranid Codex:
   -New flyer (Erinye)
   -Mycetic Spore combo-kit alternative build
   -Entirely new Monstrous Creature (the "Big Bug)
   -New elite character
   -Another one...

New Tyranid plastic kits:
Warrior - Shrike: 3 model kit.
HiveGuard - Tyrantguard: 3 model kit. New weapon option for Hiveguard, Full lash whip-sword-claw-talon bits for Tyrant guard.
Pyrovore - Biovore - Hellevore: 1 model plastic kit. 3 plastic spore mines included.
Harpy - Eriyne: 1 model plastic kit.
Mycetic Spore: 1 model plastic kit.
Tyranid Prime: 1 model plastic kit.

source: faeit212
Termagant
Troops FOC
Unit size up to 30
Cost: 4pt
Default comes with Fleshborer

Upgrades:
Fleet for 1pt per model

+1 pt Spike Rifles
+2 pt Spinefists (now Assault x(minimum of 2) Twinlinked)
+4 pt Devourers

1 per 10 can take:
+10 pt Strangleweb
+15 pt Electroshock Spitter (S4 AP6 Template Assault 1)

+1 Adrenal Glands - Fleet and Furious Charge
+1 Toxin sacs - Poison (affects cc attacks)
+2 Toxic grubs - Poison (affects ranged fire)