Why is "an" (instead of "a") used before newt?

>> Why is "an" (instead of "a") used before newt?
Because that is an error.

1.) After initially seizing and beginning to swallow a newt, many snakes subsequently release the newt after as much as one hour of holding the prey item in the mouth and upper digestive tract.

2.) The tail sweep of a tuna, a newt, a crocodile, or a whale is the leverage act of the backbone pushing water with the expanded tail.
https://en.oxforddictionaries.com/definition/newt

newt is a small animal with a long body,four legs and a tail,that lives in water.
know--knew--known=knew=k
In English the vowel are a,e,i,o,u,and sometimes y.
newt sounds like knew=k,not "h" silent,by letting your breath flow out without closing any part of your mouth or throat.It's an exception to be treated as "k"