DNA barcoding reveals a taxonomic fraud: Note on validity of Propomacrus muramotoae (Coleoptera, Scarabaeidae)

Abstract

Until the early 2000s, the genus Propomacrus was known to comprise two species, occurring in the Eastern Mediterranean and Southeast China. The discovery of Propomacrus muramotoae Fujioka in Tibet and subsequently in Bhutan and Nepal, might play a crucial role in bridging the geographical distribution gap of the Euchirini tribe between the Mediterranean and Central China, offering profound insights into its evolution and biogeography. However, all specimens, including the holotype specimen, were sourced from a single insect vendor, with no further specimens found or catalogued in museum collections thereafter. During our examination of a P. muramotoae specimen from a private collection in South Korea, we found its COI gene sequence to be identical to that of P. bimucronatus (Pallas) from Turkey, a species known for its wide distribution and genetic variability across regional populations. This overlap in genetic identity raised significant doubts, further compounded by our detection of deliberate modifications in essential diagnostic features during morphological examination. All three specimens we examined showed crude modifications, including staining and artificial grinding. Despite our inability to access the P. muramotoae type specimens for direct examination—a challenge we attempted to overcome through various means—it is evident that significant fraudulent tampering has occurred with the P. muramotoae specimens. Therefore, a new synonymy is proposed: Propomacrus bimucronatus Pallas, 1781 = P. muramotoae Fujioka, 2007 (syn. nov.). We also advocate for a straightforward verification of the type specimen through molecular analysis of the COI barcode region and morphological re-examination under a microscope for those who have access to the type specimens.