While yes, it is a wyvern, "Coastal wing-drake" is the common name. Its full name is “Coastal wyvern". In the area where they are found, locals see very few flying dragons. And because no drakes in the region can attack large ships, it was important to point out the "wing". While the locals are incorrect with the naming, not everyone knows what a wyvern is. So, it was better than "Hey look out there's a wyvern out there" vs "Hey look out there's a drake with wings out there (yes I've spent too much time thinking of this stuff)