Bad article is bad. Here's a link to a NY Times one. But basically, this isn't a discovery of a new specie, it's scientists training existing bacteria to use arsenic instead of phosphorus.
exactly. there is so much hype about this that it makes your head spin. let's do a quick recap:
we're a carbon based life form, not phosphorous based. we use it, we like it, it's quite nice because we can metabolize it easily and it could store a lot of energy in a convenient form (atp).
arsenic is bad, because it works almost like phosphor, so when we ingest arsenic, it gets metabolized in the same way as phosphor and then the metabolic path breaks because it could not do some of the stuff phosphor does, so it clogs down our metabolic system
also, when it get properly metabolized, it's highly unstable, so stuff built with arsenic tend to come apart at the worst time due to the lower binding potential (it's a stretch of what it's happening, let it pass for sake of clarity)
so phosphorous based dna breaks and atp doesn't work right. I don't know if it could be build also in something that resembles phospholipids, but it would be just as bad.
so, what gives? there is this lake, high in arsenic, where bacteria were found. so scientist started to wonder how did they survive, if they can discriminate arsenic and discard it or if they can manage to make arsenic molecules strong enough to be stable, and how
so what they did? take some bacteria, put them in two group, one growing with lot of phosphor and the other with very very low phosphor and high arsenic.
then they took the arsenic surviving bacteria and compared it to the others. they were found to indeed contain arsenic based molecules, and they found that those molecules went as far as being in their dna. they found that arsenic grown cells were bigger, but is still uncertain to how this helps to maintain arsenic molecules stable.
those are stil carbon based life form, and not of any different kind from what we know about life. they have the same basic metabolism, they works using the same dna we found in almost every other lifeform, and they're not arsenic based.