The second-weakest Lawful anttaur is the warrior. I'm fairly sure these still can't use weapons: just look at the croissant-like lobster claws they have in their official picture. The description confirms they can't speak either.
Warriors are Medium, with good physical stats and average (or above-average) mental ones. They're just as quick as workers, have many of the same immunities in addition to SR (pretty good SR, too), and, most importantly, four natural weapons. The bite is not much (Mouthpick it is), but the claws and sting are okay. Warriors also inject a strength-damaging poison with each sting attack. Sadly, it won't do much in combat.
You see, there's basically two ways to use poison in D&D. One can use poison that damages a foe's low stats, in hopes of reducing those to 0 (thereby practically guaranteeing victory), or one can use poison that damages a foe's important stats, debuffing said foe's important abilities. A warrior's weak strength-damaging poison, however, is bad at both. It's too weak to instantaneously knock out foes, while anything with high strength will typically also have high fortitude saves.
So are four outsider HD worth everything a worker could've gotten you, plus SR, better abilities, and extra natural weapons? I'm tending towards 'no'. +0 LA, though I understand if people disagree here.