Humanoids with webbed hands whose culture treats courtesy as a form of dishonesty and values blunt, direct speech.
The Zaldans are a humanoid species with webbed hands. Their culture regards courtesy as a form of dishonesty that hides true feelings, so polite behaviour offends them and they value blunt honesty above all else.
In Coming of Age, Wesley Crusher competed for a place at Starfleet Academy against several other candidates, among them the Zaldan Rondon. When others treated Rondon with ordinary politeness, he took it as an insult and grew angry, and Wesley avoided a fight by understanding how Zaldans view such behaviour.