Mimarachnidae is an extinct planthopper family of the superfamily Fulgoroidea, with a broad geographical distribution, known exclusively from the Cretaceous. Here, a new fossil species of Ayaimatum Jiang and Szwedo, 2020, Ayaimatum minutum sp. nov., is described and illustrated on the basis of two specimens from the mid-Cretaceous amber of northern Myanmar. We herein revised the diagnostic characters of Ayaimatum, and the intra-specific variation of A. minutum is discussed. Additionally, a new genus and species of Mimarachnidae, Mimaeurypterus burmiticus gen. et sp. nov., from the same Burmese (Myanmar) amber, is herein described. Mimaeurypterus gen. nov. can be distinguished from other mimarachnids by its large body size, mesonotum with median carinae not reaching anterior margin, msoscutellum without distinct wrinkles, and broad, coriaceoustegmina with apical margin truncate. The new discovery further confirms that this extinct hemipteran group was diverse and had high morphological disparity during the late Mesozoic. (C) 2020 Elsevier Ltd. All rights reserved.