Miembros del Grupo de Biología Evolutiva de la UNED han presentado durante la 22a edición de la EAVP la comunicación titulada “New squamate specimens from the Kimmeridgian Guimarota fossil site (Portugal)”. En esta comunicación se han presentado varios restos vertebrales correspondientes a un lagarto escamoso (Squamata) de Jurásico Superior de Portugal. Así, se hace una descripción anatómica y atribución sistemática preliminar de dichos elementos vertebrales, siendo atribuidos a Anguimorpha. A continuación, os dejamos el resumen perteneciente a este trabajo:
The former Guimarota coal mine, located near Leiria, in the west-central region of Portugal, is recognized as one of the most significant Upper Jurassic microvertebrate fossil localities worldwide. The vertebrate-bearing lignite coal layers have been interpreted as belonging to the Alcobaça Formation and dated to the early Kimmeridgian based on ostracods. This site is particularly renowned for its abundant and diverse fossil record of early mammalians, but a wide array of other vertebrates, including actinopterygians, amphibians, lepidosaurs, turtles, crocodyliforms, dinosaurs, and pterosaurs, have also been recovered. A set of previously undescribed, relatively well-preserved, isolated vertebrae from Guimarota, housed in the Museu Geológico (MG) in Lisbon and mislabelled as belonging to theropod dinosaurs, is described here, and its taxonomic identification is reassessed. These specimens include a cervical (MG 28959) and four dorsal (MG 28954, MG 28955, MG 28958, MG 28960) vertebrae, which are reinterpreted as belonging to small squamates. This interpretation is based on the procoelous morphology of the centra, the presence of anteroposteriorly narrow and dorsoventrally elongate paradiapophyses, and a poorly developed zygosphene-zygantrum complex (recognized in some dorsal vertebrae). The mostly straight axis of the cotyle-condyle system and the internal structure, composed of several small cavities visible in both the centrum and neural arch, indicating non-pachyostotic vertebrae, are features shared with most Pythonomorpha. However, the poorly developed zygosphene-zygantrum complex allow us to exclude the possibility that the specimens from Guimarota belong to this clade. These specimens share several features with other vertebrae from Guimarota previously attributed to indeterminate anguimorphs, including anteriorly broadened centra with ventrally smooth surfaces, as well as a shortened, broad condyle and a broad, elliptical cotyle. Based on these features, the isolated vertebrae described here are reinterpreted as belonging to Anguimorpha. The study of these specimens contributes to our understanding of the squamate diversity at Guimarota and provides new data to better characterize the poorly documented axial skeleton of the anguimorphs from this locality.
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