I am 99% certain I have both ventricosa and Xventrata... the colouration can be very similar, the squat bulbous shape of ventricosa is not very pronounced when they are young... If you have both, the differences become quite noticeable side by side as they age; if you just have one plant, it's a bit tricky but this is how mine compare, maybe it could help:
-the peristome ridges on ventrata are very thin and close together, more so than on ventricosa.
-ventrata is more shiny, both the peristome and outside of the pitcher.
-in a side view, the ventrata peristome slopes more sharply than ventricosa (tilts up to the lid at a sharp angle, ventricosa peristome is less angled) Ventrata has a very distinctive side shape... the ventricosa when young was similar but the pitcher mouths always seemed to lie flatter than on the ventrata.
-ventrata produces a ton of nectar drops all over the leaves and outside surface of the pitchers... ventricosa not so much but its "mouth waters"... there is always liquid on the lip of the peristome.
-looking into the mouth, the inside surface at the back of the pitcher is very light and whitish/greenish in ventrata, ventricosa the inside is less contrasting (more beige/rosy)
-tendril length vs. pitcher height... my ventrata has tendrils that are usually longer than the pitchers... the ventricosa tendrils are usually shorter than the pitchers (so the ventricosa pitchers sort of 'sit up higher')
-the older the plants, the more they differ... mine looked identical this spring, they are now very different. The ventricosa picture from malesiana tropicals is maybe not the best for comparison... I will try to dig up some pictures of the other colour forms which are more common.
Looks like a ventricosa to me, judging by the large pitcher on the right.