The Freixial Formation is a Late Jurassic geologic formation with outcrops in central Portugal. The formation has produced the fossils of many vertebrates, including non-avian dinosaurs. It was deposited during the Tithonian age of the Late Jurassic.
Stratigraphy and paleoenviroment Outcrops of the Freixial Formation are located in the Lusitanian Basin of Central Portugal. It is considered to represent the youngest Jurassic rocks in the region, and it overlies the more well-known Lourinhã Formation. The depositional environment is interpreted as comprising deltaic and distal fluvial environments. The formation was deposited during the Tithonian age, spanning around . The thickest outcrops are tall. It had once been considered synonymous with the Assenta Member of the Lourinha Formation, but more papers treat the Freixial Formation as a distinct unit. In the south of the basin, it interfingers with rocks of the Lourinha Formation.
Fossil content
Dinosaurs
Ornithischians Ornithischians of the Freixial FormationGenusSpeciesLocationStratigraphic positionMaterialNotesImage Dacentrurus D. armatus Tithonian Skeletal remains A large dacentrurine stegosaurid Ankylopollexia indet. Indeterminate Tithonian Femur An ankylopollexian ornithopod similar to Camptosaurus. Dracopelta D. zbyweski Tithonian Fragmentary remains An early ankylosaur Ornithopoda indet. Indeterminate Tithonian Footprints Various large and small footprints, with smaller footprints interpreted as coming from a dryosaurid and larger footprints interpreted as coming from large, Camptosaurus-like taxa. Dryosauridae indet. Indeterminate Tithonian Skeletal remains A dryosaurid ornithopod. Remains of indeterminate dryosaurids.
Sauropods Sauropods of the Freixial Formation Genus Species Location Stratigraphic position Material Notes Images Lusotitan L. atalaiensis Tithonian Caudal vertebrae A brachiosaurid sauropod. Freixial material originally regarded by Mannion and colleagues as indeterminate. Thus the Freixial material is referrable to Lusotitan. However Mocho and colleagues noticed depressions on the front of the posterior caudal vertebrate of the Freixial specimen,a diagnostic trait of Lusotitan. Diplodocinae indet. Indeterminate Tithonian Variety of material A diplodocine diplodocid. Various remains of indeterminate diplodocine, including a large () femur Camarasauridae indet. Indeterminate Tithonian Neural spine and partial skeletons A camasasaurid sauropod. Remains of indeterminate camarasaurids Turiasauria indet. Indeterminate Tithonian Teeth A turiasaur. Teeth attributed to Indeterminate turiasaurians
Theropods Various theropod teeth from the Freixial Formation have been referred to the genera Allosaurus, Torvosaurus, and Ceratosaurus on the basis of cladistic and multivariate analysis. According to Mateus et al. 2024, a combination of both methods is strong enough to confidently assign teeth on the genus level.
Theropods of the Freixial Formation Genus Species Location Stratigraphic position Material Notes ImagesAllosaurusA. sp. Tithonian Teeth A allosaurine allosauridTorvosaurusT. sp. Tithonian Teeth A megalosaurine megalosaurid Ceratosaurus C. sp. Tithonian Teeth A ceratosaurid ceratosaurLusovenatorL. santosi Tithonian Articulated caudal vertebrae A carcharodontosaurian theropod
Turtles Turtles of the Freixial Formation Genus Species Location Stratigraphic position Material Notes Images Hylaeochelys H. kappa Tithonian A plesiochelyid thalassochelydian Plesiochelys P. sp. Tithonian A plesiochelyid thalassochelydian Tropidemys T. sp. Tithonian A plesiochelyid thalassochelydian
Mammals Mammals of the Freixial Formation Genus Species Location Stratigraphic position Material Notes Images Cambelodon C. torreensis Tithonian Cranial material A pinheirodontid multituberculate
References