其实同not...until是一样的,只不过否定前移需倒装,Not until 5 o'clock did he come back home.=He didn't come back home until 5 o'clock.
until一直到...,not until直到...才.../...之前没做...
Wait until I call you.(一直等到我打电话给你）
He didn't come until 5 o'clock.(直到5点他才来/五点之前他没来）
People didn't find that kind of animals until 19th century