Sure. "Présentateur/présentatrice" = presenter, announcer, newscaster, or in gender-specific terms, an anchorman or anchorwoman. And no, you don't have to say "anchorwoman" or "anchorman". You may use the generic "announcer" or "news anchor".
English is weird when it comes to gender (just like most languages!). I'd never use "hostess" for a female presenter, calling her a "host" instead. I'd only use "hostess" for a flight attendant or someone who had organised a get together.
What's the difference between my answer and duolingo answer:
my answer - the eight O'clock news has a new announcer.
Duolingo - the news has a new eight O'clock announcer.
???? The meaning is the same as Duo.