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Freixial Formation

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.

Freixial Formation
Stratigraphic range: Tithonian[1]150.8–146.5 Ma

Stratigraphy and paleoenviroment

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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 150.8 to 146.5 million years ago. The thickest outcrops are 150 metres (490 ft) 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.[2] In the south of the basin, it interfingers with rocks of the Lourinha Formation.[3][1][4]

Fossil content

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Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
 Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

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Ornithischians

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Ornithischians of the Freixial Formation
Genus Species Location Stratigraphic position Material Notes Image
Dacentrurus[5] D. armatus Tithonian Skeletal remains A large dacentrurine stegosaurid
Ankylopollexia indet.[6] Indeterminate Tithonian Femur An ankylopollexian ornithopod similar to Camptosaurus.
Dracopelta[5] D. zbyweski Tithonian Fragmentary remains An early ankylosaur
Ornithopoda indet.[7] 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.[8] Indeterminate Tithonian Skeletal remains A dryosaurid ornithopod. Remains of indeterminate dryosaurids.

Sauropods

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Sauropods of the Freixial Formation
Genus Species Location Stratigraphic position Material Notes Images
Lusotitan[9][5][10][11] 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.[5][12] Indeterminate Tithonian Variety of material A diplodocine diplodocid. Various remains of indeterminate diplodocine, including a large (150 cm (59 in)) femur
Camarasauridae indet.[5] Indeterminate Tithonian Neural spine and partial skeletons A camasasaurid sauropod. Remains of indeterminate camarasaurids
Turiasauria indet.[5] Indeterminate Tithonian Teeth A turiasaur. Teeth attributed to Indeterminate turiasaurians

Theropods

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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.[2] According to Mateus et al. 2024, a combination of both methods is strong enough to confidently assign teeth on the genus level.[13]

Theropods of the Freixial Formation
Genus Species Location Stratigraphic position Material Notes Images
Allosaurus[2] A. sp. Tithonian Teeth A allosaurine allosaurid
Torvosaurus[2] T. sp. Tithonian Teeth A megalosaurine megalosaurid
Ceratosaurus[2] C. sp. Tithonian Teeth A ceratosaurid ceratosaur
Lusovenator[14] L. santosi Tithonian Articulated caudal vertebrae A carcharodontosaurian theropod

Turtles

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Turtles of the Freixial Formation
Genus Species Location Stratigraphic position Material Notes Images
Hylaeochelys[15][16] H. kappa Tithonian A plesiochelyid thalassochelydian
Plesiochelys P. sp. Tithonian A plesiochelyid thalassochelydian
Tropidemys T. sp. Tithonian A plesiochelyid thalassochelydian

Mammals

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Mammals of the Freixial Formation
Genus Species Location Stratigraphic position Material Notes Images
Cambelodon[1] C. torreensis Tithonian Cranial material A pinheirodontid multituberculate

References

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  1. 1 2 3 Carvalho, Victor F.; Camilo, Bruno; Araújo, Ricardo; Castro, Lígia; Kullberg, José C.; Desmet, Hilde G. B.; Nerinckx, Ignace; Leite, Marco; Reis, Diego (2025). "Cambelodon torreensis , a new pinheirodontid multituberculate from the Upper Jurassic of western Portugal". Papers in Palaeontology. 11 (2) e70012. Bibcode:2025PPal...11OA.R2C. doi:10.1002/spp2.70012.
  2. 1 2 3 4 5 Malafaia, Elizabete (2017). "Phylogenetic analysis, paleoenvironmental and paleobiogeographic interpretation of theropod dinosaurs from the Upper Jurassic of the Lusitanian Basin".
  3. ↑ Myers, Timothy; Mateus, Octávio; Tabor, Neil; Jacobs, Louis (2012-01-01). "Palaeoclimate of the Late Jurassic of Portugal: comparison with the Western United States". Sedimentology. 59 (6): 1695–1717. Bibcode:2012Sedim..59.1695M. doi:10.1111/J.1365-3091.2012.01322.X.
  4. ↑ Pierce, Colm. "Life at the continental–marine interface: palaeoenvironments and biota of the Alcobaça Formation (Late Jurassic, Central Portugal), with a formal definition of the unit appended". Palaeobiodiversity and Palaeoenvironments. doi:10.1007/S12549-021-00496-X.
  5. 1 2 3 4 5 6 Mocho, Pedro (2017). "Upper Jurassic sauropod record in the Lusitanian Basin (Portugal): Geographical and lithostratigraphical distribution" (PDF).
  6. ↑ Galton, Peter (2009). "Notes on Neocomian (Lower Cretaceous) ornithopod dinosaurs from England - Hypsilophodon, Valdosaurus, Camptosaurus, Iguanodon - and referred specimens from Romania and elsewhere".
  7. ↑ Malafaia, Elisabete (2017). "Tracking Late Jurassic ornithopods in the Lusitanian Basin of Portugal: Ichnotaxonomic implications" (PDF).
  8. ↑ Escaso, Fernando; Ortega, Francisco; Malafaia, Elisabete; Mocho, Pedro; Narváez, Iván; Silva, Bruno Camilo; Gasulla, José Miguel; Sanz, José Luis (2015-07-08). "New dryosaurid-bearing beds from the Upper Jurassic of Portugal". ResearchGate. Archived from the original on 2015-10-29. Retrieved 2026-02-14.
  9. ↑ Mocho, Pedro (2016-01-01). "Systematic review of Late Jurassic sauropods from the Museu Geológico collections (Lisboa, Portugal)". Journal of Iberian Geology. doi:10.5209/REV_JIGE.2016.V42.N2.52177.
  10. ↑ Mannion, Philip D.; Upchurch, Paul; Barnes, Rosie N.; Mateus, Octávio (May 2013). "Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms: Lusotitan and Titanosauriform Evolution". Zoological Journal of the Linnean Society. 168 (1): 98–206. doi:10.1111/zoj.12029.
  11. ↑ Mocho, P.; Royo-Torres, R.; Ortega, F. (2017-08-18). "New data of the Portuguese brachiosaurid Lusotitan atalaiensis (Sobral Formation, Upper Jurassic)". Historical Biology. 29 (6): 789–817. doi:10.1080/08912963.2016.1247447. ISSN 0891-2963.
  12. ↑ Mocho, Pedro (2016-01-01). "Systematic review of Late Jurassic sauropods from the Museu Geológico collections (Lisboa, Portugal)". Journal of Iberian Geology. doi:10.5209/REV_JIGE.2016.V42.N2.52177 (inactive 18 January 2026).{{cite journal}}: CS1 maint: DOI inactive as of January 2026 (link)
  13. ↑ Burigo, André; Mateus, Octávio (2024-12-30). "Allosaurus europaeus (Theropoda: Allosauroidea) Revisited and Taxonomy of the Genus". Diversity. 17 (1): 29. Bibcode:2024Diver..17...29B. doi:10.3390/d17010029. ISSN 1424-2818.
  14. ↑ Malafaia, Elisabete; Mocho, Pedro; Escaso, Fernando; Ortega, Francisco (2020-01-02). "A new carcharodontosaurian theropod from the Lusitanian Basin: evidence of allosauroid sympatry in the European Late Jurassic". Journal of Vertebrate Paleontology. 40 (1) e1768106. Bibcode:2020JVPal..40E8106M. doi:10.1080/02724634.2020.1768106. ISSN 0272-4634.
  15. ↑ Adán Pérez-García; Francisco Ortega (2014). "A new species of the turtle Hylaeochelys (Eucryptodira) outside its known geographic and stratigraphic ranges of distribution". Comptes Rendus Palevol. 13 (3): 183–188. doi:10.1016/j.crpv.2013.10.009.
  16. ↑ Pérez-García, A.; Camilo, B.; Ortega, F. (2023). "New Data on the Poorly Known Jurassic Record of the Turtle Hylaeochelys (Thalassochelydia), Based on New Finds from Portugal". Diversity. 15 (2). 167. Bibcode:2023Diver..15..167P. doi:10.3390/d15020167.
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