Why aren't the contacts that are displayed on Whatsapp not seen in the phonebook on my Sony Z3 Lollipop?

[AC Question]

contacts are deiplayed on whatsapp not ssen on phnebook sonny Z3 lollipop

i can see the contacts in whatsapp but not displayed in phone book , i go to whats-app try to add them # its says view in phone book ( means its available but cannot see it)