Barbgaunt
Barbgaunts are a new species hailing from the Gauntii genus that first made its debut in 10th Edition. They are one of the two new Gaunt species being introduced, with the other being the Neurogaunts.
Overview
Barbgaunts are a Tyranid light artillery-organism, working closer to the front line than Hive Guard and Biovores. If anything, Barbgaunts are basically baby Biovores for all intents and purposes. But in terms of their nature, they heavily resemble dedicated light artillery with airburst munitions than anything else. True to most Tyranid artillery units, the bio-cannons on their backs are actually bonded with the same parasitic organism that has enslaved the rest of the gaunt to its will, merging body and weapon into a single lethal entity.
It does come at a cost though. Their heavy weaponry forces the Barbgaunt to adapt to a more tripodal position, making them comparatively slow, awkward and sluggish compared to their more nimble cousins. It's unclear if they have to walk as a tripod or if they only need to brace themselves on three legs when firing.
Crunch
Crunchwise, Barbgaunts have the same stats of all Gaunts which is not surprising. Their biggest gimmick of course, is their unique weapon they carry. Their light bio-canons is 24" ranged Blast and Heavy weapon with a D6 Attack, BS4+, S5, AP0, D1 light mortar. Whilst not that powerful when compared to other forms of light artillery, the weapon or...shall we say the Gaunt itself, is comparatively cheaper. So you field more of them.
Another unique factor is that, to balance its relatively mediocre stats, these living mortars have a unique ability called Disruption Bombardment. What this thing does is that in your shooting phase, any targeted enemy infantry that was hit by one or more of these attacks counts as disrupted for the next turn. When a unit is disrupted, they subtract 2 from its Move characteristic and 2 from its Advance and Charge rolls made for it.
So yeah, imagine fielding a bunch of miniature Tremor Cannons. A very interesting and useful but annoying weapon against charge armies.