A new fossil genus and species of Cantharidae, Nothotytthonyx serratus Li, Biffi, Kundrata & Cai gen. et sp. nov., is reported from mid-Cretaceous Burmese amber. The new species is tentatively attributed to the extant subfamily Malthininae based on a combination of characters, including the symmetrical apical maxillary palpomeres, shortened elytra, pronotum with arched margins and well-defined borders, tibiae with apical spurs, and tarsal claws simple, although its well-developed gonostyli are atypical in Malthininae. The discovery of Nothotytthonyx also suggests a possible Gondwanan origin for Malthininae.