First anguid record (Anguidae, Squamata) from the Late Miocene Konservat-Lagerstätte Libros (Teruel, Spain) and its palaeoenvironmental implications

For the first time, fossil evidence of anguine material is reported from the middle–late Tortonian Konservat-Lagerstätte locality of Libros (Teruel, Spain). So far, only mammals, birds, snakes, amphibians, insects and flora in excellent conditions of preservation were described from the lacustrine sediments of this site. The size and fragility of the new fossil, partially embedded in the sediment, required the application of non-invasive techniques for their study. Micro-CT scans were conducted, resulting in satisfactory three-dimensional models. The skeleton is partially articulated and preserves the nasal bone, dozens of vertebrae, eleven ribs and hundreds of osteoderms. Amongst them, the two best-preserved trunk vertebrae and one caudal vertebra, along with osteoderm dermal sculpturing, suggest attribution to the genus Pseudopus (Family Anguidae). This new fossil record not only provides information from a global palaeobiogeographical perspective, but also constitutes a valuable contribution to the understanding of the ecosystems surrounding the Libros palaeolake.