"Surface similarities" refer to similarities that are apparent or easily observed, but do not necessarily reveal or indicate deep or significant connections or similarities. Full definition
Rose Nestler's installation emulates the hue surface similarities between lavishly upholstered objects and smooth undulating rock forms. (artistsallianceinc.org)
As a result, these relationships are frequently classed together on the basis of surface similarities, despite important structural and functional differences. (cambridge.org)
With West, Leone made certain that surface similarities existed between the film's characters and those found in The Good, the Bad, and the Ugly — Charles Bronson's stoic harmonica - playing loner can be equated with Eastwood's «Good» Man With No Name; Henry Fonda's vicious Frank is Lee Van Cleef's «Bad» Sentenza; and Jason Robards's wily bandit Cheyenne is Eli Wallach's «Ugly» Tuco. (slantmagazine.com)