RT Journal Article T1 New discoveries of vertebrate remains from the Triassic of Riba de Santiuste, Guadalajara (Spain) A1 Berrocal-Casero, Mélani A1 Audije-Gil, Julia A1 Alexandre Castanhinha, Rui A1 Pérez Valera, Juan Alberto A1 Faria dos Santos, Vanda A1 Segura, Manuel AB The palaeontological sites of Riba de Santiuste and Sienes (Riba de Santiuste area) are located in the province of Guadalajara, Spain. They include a stratigraphic interval in Muschelkalk facies belonging to the “Cuesta del Castillo Sandstones” Formation and “Royuela Dolostones, Marls and Mudstones” Formation. These sites include numerous fossil plants, direct vertebrate remains, and vertebrate swim traces. The vertebrate remains correspond to a multitude of anatomical elements of Sauropterygia (Nothosauroidea, Placodontia) and possible Archosauria (Rauisuchia) remains. The fossil material attributed to nothosaurs includes teeth, coracoids, a thoracic vertebra, some isolated vertebral centra, humerus, rib fragments, and some dorsal and caudal vertebrae. The remains attributed to placodonts correspond to fragments of skull, quadrate, teeth and osteoderms. Other undetermined sauropterygian remains, such as ulnas, fragments of long bones, fragments of ribs, and articular facets of ribs have been also recovered. Additionally, a fragment of mandible and an intervertebral disk of indeterminate reptiles whose size could be compatible with archosaurs are also described. These bones are exceptionally well-preserved because the fossilization processes have preserved the microstructure of the tissues. The sites also show vertebrate traces, with parallel scratch impressions interpreted as swim traces. The relative stratigraphic position and the palaeontological content of these sites suggest a Ladinian age (Middle Triassic). The interpretation of the sedimentary facies here described also suggests that the sites could correspond to detrital-carbonate mixed deposits of coastal intertidal to supratidal environments. PB Elsevier SN 0016-7878 YR 2018 FD 2018 LK https://hdl.handle.net/20.500.14352/13023 UL https://hdl.handle.net/20.500.14352/13023 LA eng NO Ministerio de Economía y Competitividad (MINECO) NO Universidad Complutense de Madrid DS Docta Complutense RD 24 abr 2025