Assuming that the fossil guy even has his facts correct, this article shouldn't trumpet the "unexpected" word as if everyone should be stunned. It is in fact more a testimony as to how some scientists can be so technically bright while being so vision-dull.
It is extremely likely that all animals of any size came from aquatic ancestry --- this is un-debated by all except Creationists. When "things" of size came onto land, WELL onto land and ultimately became true landlubbers, they crawled and "heaved" themselves up, using "paddles" or primitive "legs". Natural selection pressures (well known to convergent evolutionists) forced the bisymmetrically-placed four limb format to win the struggle for existence, and all large land-roving animals got that plan. {there are very good reasons as to why little things like insects did not.} The better, faster moving "walkers" would outcompete the only other plan-design form which could compete, the no-limbed "slitherers", for the vast majority of food niches. The slitherers were reduced to food niches right on the ground, and probably right on the shores to begin with. The four-limbs took the high ground, and literally looked down upon the slitherers who became prey if anything.
So why would we get a primitive snake with legs? A simple guess would be that back in the "good ole days" of the Cretaceous, or whenever it really started, all the early slitherers had lost the game to the fast-movers. Except for semi-aquatic slither-swimmers, they probably didn't even exist. But as land life diversified, new niches opened up and gave opportunities for low-slung reptiles to creep into them. The most amazing awkward evolutionary trial-and-errors occur when there are new niches to be occupied --- Darwin's finches are an example --- most of those things would go immediately extinct if mainland better-adapted birds were introduced. The key for the push to "lose legs" and become a slitherer had to be, finally, the existence of rich food niches for small reptiles to feed on near the floor, which the Big Boys had moved beyond. If it became advantageous to feed off of these niches while hiding from the monsters by slithering inside narrow crevices and into holes, legs would become more of a risk than a reward --- Nature never tolerates that.
The other thing that indicates the poverty of the mind of the bricklayer palaeontologist compared to the world-envisioning type, is that they somehow forget that they have such a tiny set of windows on the world's past to work with. This sort of try-legs, try-none, try-legs, try-none "dance" of evolutionary empowerment probably happened several times in many different continental environments.
Was it interesting that the guy found a snake [pre-snake] with four legs? Yes. Was it Earth-shaking? Shouldn't be. Should we take comments like the legs were used to hold mates or prey seriously? Better just to laugh and roll eyes. But Sex and Violence sells, even in Science.
