We reassessed the taxonomic status of the xenodontine snake Erythrolamprus bizona Jan (1863) based on a comprehensive review of literature records and comparative material. Our data demonstrate that the original diagnosis does not allow the unambiguous attribution of the name E. bizona to any population of the genus. After a thorough investigation in European institutions, we recovered two syntypes of the E. bizona type-series, confirming its composite nature. To circumvent the problem, we herein designate a lectotype for the species, providing a reformulated diagnosis and a detailed redescription. The lectotype represents one of the rare remaining specimens used in Giorgio Jan’s original descriptions during the second half of 19th century, and is housed in the Museo Civico di Storia Naturale di Milano, Milan, Italy. For more than seven decades, herpetologists have assumed that such material had been lost forever due to bombings of World War II. Nonetheless, our finding corroborates recent studies demonstrating that at least some of Jan’s snake types still exist for taxonomic research. Finally, we discuss the geographic congruence of the frequency distributions of segmental counts under an integrative approach aiming to maintain nomenclatural stability without ignoring preliminary evidence of taxonomic diversity.