People haven’t emphasized this enough, but these things do a LOT of damage in the wild too so you need to be really careful while trying to tame them. Specifically the R variant, which I have been taming on Fjordur can just shred through your tames and you. They can also shoot you while your on a mount.
Never underestimate these bastards, I was trying to tame one of them and THEIR NEEDLES HAVE RANGE! I was on the other side of the lake in the desert biome and I was getting aim boted by thier needles. MAKE SURE TO HAVE SOME MED BREWS IF U TRY TO TAME ONE!
The developers made a very correct decision for this beast and made a not very large radius of its aggression. If he would have a higher target radius (like a raptor, for example), he will start shooting for the first step, and it will be very annoying for all players.
NEVER UNDERESTIMATE THESE GUYS, they are able of dispatching your tamed velonasaur in seconds because unlike ridden velonasaurs. They can fire at a longer and more rapid rate. If your velonasaur is un-mounted, then it may very well be able to kill the wild velonasaur!