On the type series of Lacerta teguixin Linnaeus, 1758 (Squamata: Teiidae)

Tupinambis teguixin (Linnaeus, 1758), one of the largest South American lizards, has a complex nomenclatural history. It was originally named Lacerta teguixin, and a specimen housed in the Uppsala Universitet (UPSZTY 13) was designated the lectotype. Sometime after the 1990's, the lectotype desiccated, and in 2012, a specimen housed in the Swedish Museum of Natural History (NRM 121) was designated as a "neolectotype". However, the term "neolectotype" has no standing under the International Code of Zoological Nomenclature, and such a designation is invalid. The type series of Lacerta teguixin most likely included three specimens: one (possibly lost) illustrated in Albertus Seba's "Locupletissimi Rerum Naturalium Thesauri", UPSZTY 13 (lectotype), and NRM 123 (paralectotype). Specimens NRM 121 and 122 cannot be confirmed as syntypes, and their status remains uncertain. Additionally, Seba's specimen might belong to Tupinambis cryptus, making the T. teguixin type series potentially composed of two species. Our review highlights the importance of thorough historical and nomenclatural research before changing type designations to ensure stability and compliance with the Code.