The list, released on Wednesday (Sept 13), includes Elmet by Fiona Mozley, a 29-year-old British bookseller whose manuscript had not even been published when she got longlisted, and History Of Wolves by American author Emily Fridlund.
Colson Whitehead's The Underground Railroad, already the victor of the 2017 Pulitzer prize for fiction, the 2016 National Book Award for fiction and the Arthur C Clarke award for science-fiction, is a surprise omission from the literary award.
The prize, subject to intense speculation and a flurry of betting, usually brings the victor a huge boost in sales and profile.
Arundhati Roy's novel The Ministry of Utmost Happiness could not find a place on the shortlist.
U.S. author Paul Beatty won in 2016 was for his novel "The Sellout".
The change spurred fears among some British writers and publishers that it would bring USA dominance to a prize whose previous winners include Salman Rushdie, Ben Okri, Margaret Atwood and Hilary Mantel.
She stressed that the decision made was not on the basis of the authors' nationality or gender but on the content of the novels.
Thirty percent of the 144 books submitted by publishers were American, slightly down on a year ago.
The shortlist for the £50,000 literary prize was chosen by a panel of judges that included literary critic Lila Azam Zanganeh, Man Booker Prize shortlisted novelist Sarah Hall, artist Tom Phillips, travel writer Colin Thubron and was chaired by Baroness Lola Young.
Young said discussion had been "robust", but there had been "no fights - yet".