By Simon Marshal

Out with the Old, and in with the new.

For those eagerly awaiting the release of the new Tyranid Codex your wait is now over. This month sees the Devourer of Worlds new form unleashed onto the unsuspecting populace of millions of planets across the galaxy.
For all those Nid fans and enemies of the Hive Mind out there, I shall endeavor to give a brief overview of the changes wrought by the new book.

Besides being crammed full of background fluff and very cool pictures the codex has a vast array of new and reviewed changes bound within its pages.
I'll start by listing the new special rules then move onto Bio weapons, Hive Mind powers, Biomorphs and finally any big changes to the critters.

First off let me start with the new Tyranid Special Rules. They are as follows.

Synapse power
Besides the old rules there's an added immunity to instant death from double strength hits. This now means that units with more than one wound backed up by synapse creatures will never take more than one wound from a single hit no matter the strength.
Instinctive behavior
No more rolling of the dice. It now depends on what it is you want to do. You have a choice of passing a leadership test to move normally, not rolling and just lurking to gain a better cover save or falling back towards the nearest synapse creature.
Move through cover
It now works as the rule in the rulebook
Living ammunition
Those weapons that fire living ammunition now get a second chance to wound.
Spore Mines
Spore mines now work in clusters, when one moves, detonates or dies they all do.

Bio Weapons

Barbed stranglers, Devourers and Deathspitters all get range increases. All weapons now have a max strength and carrying two of the same weapons now makes them twin linked.

New Hive Mind Powers
Warp Blast and The Horror don’t change.
Catalyst and Psychic Scream have an increase in range.
Warp Field now gives an invulnerable save as well as the armor save.
The Shadow in the Warp (New Psychic Power) makes it harder for the enemy to use their psychic powers

New Biomorph Enhancements
Though they have dropped the mutations like hive node from the broods, I think they make up for it with the sheer amount of new biomorphs you can equip to some of the units. I'll cover most of the new stuff for you to salivate over.

Creatures with Acid Maws get re-rolls to wound in the first round of combat.

Bonded Exoskeletons get an extra toughness.

Creatures with Feeder Tendrils gain the preferred enemy special rule and units close to the model also gain the preferred enemy ability.

Leaping creatures have the long assault range (But aren’t considered Beasts) and may make their full number of attacks if within three inches not the usual two.

Creatures with either a Mace or Scythe tail get a special attack if there are a few enemy models in base contact. The Mace tail confers an extra attack a full strength, and the scythe tail confers one to three attacks at half strength.

Regenerate.
Pretty much explains it’s self really.

Reinforced Chitin
gain an extra Wound.

Tyranids with the scuttler biomorph may use the Scout special rules.

Spine banks count as being armed with frag grenades and spinefists.

Creatures with Spore Cysts may produce a toxin spore mine per turn.

Symbiote Rippers (Represented by rippers on the on the base) increase the size the model counts as for outnumbering purposes.

A Thornbacked creature doubles the number of models it counts as if on the winning side of the close combat.

Toxic Miasma reduces the enemy’s weapon skill when being targeted in close combat.

Tusked creatures get 2 attacks on the charge. (Instead of the usual 1).

Here is a list of some of the new or improved gribblys (critters). I haven’t included all of them as I don’t want to spoil the codex for those who want to buy it. (That and I could run up against some copyright laws) I've included all the major changes I could find, leaving out the slight price changes and different stat lines. Here they are.

Tyrant Guard.
Add on scything talons or lashwhips and take off the spine shield and you now have the new tyrant guard. Plus the new models look very cool.

Brood Lord.
Aside from being a synapse creature, it and its brood can infiltrate and all of its attacks count as power weapon attacks.

Lictors.
Lictors with their many special rules now deploy from terrain by deep striking from a chosen piece of area terrain and their Pheromone Trail now means you get those much needed reserves sooner, making them a tempting choice.

Genestealers.
The Genestealers can no longer infiltrate (by themselves) but they do get fleet of claw making them potentially very fast. They also have access to the Scuttler ability (if you want to spend the points).

Gaunts.
Gaunts can now be given the” Without Number” ability if they’re cheap enough. (Can anyone say cannon fodder?)

Raveners.
Ravener broods now carry their shooty weapons inside their thoraxes, leaving the hands free to rend and tear. They can also deep strike.

Spore Mine Cluster
The addition of Spore Mine clusters as a fast attack option makes a nice change. The deep striking cluster could potentially open up a hole in the enemies ranks.

Biovores.
Biovores now group together in units of 1 to 3 models and have brood telepathy (so no more annoying instinctive behavior).

And now the biggest gribbly of them all The Carnifex.
With more Biomorphs than you can shake a scything talon at, these behemoths of destruction can be fielded as elites as well as heavy support if equipped lightly. As a side note, the most expensive carnifex I could create came in at around 327pts.

So there you have it, a very brief overview of the squishy and diamond hard chitin bits of the tyranids.
I myself can't wait to get an army of these critters together.

Let the devouring of planets begin...