A new genus and species Vianathauma pericarti gen. et sp. n. (Heteroptera, Vianaididae) is described from the amber of New Jersey (Upper Cretaceous, North America). It is the second known fossil monotype genus of the family alongside with two modern genera that have been described so far. Earlier presented synapomorphies for Vianaididae and Tingidae, as well as autapomorphies for Vianaididae are also specified. Taking fossil genera Vianagramma GOLUB&POPOV and Vianathauma, n. gen. as an example, authors propose two directions of morphological differentiation of Mesozoic Vianaididae. In the Cenozoic, one of these directions caused formation of specific coleopteroid myrmecophilous forms with punctate but no areolate hemelytra.