Freixial Formation

Freixial Formation
Stratigraphic range: Tithonian[1]

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 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]

Vertebrate paleofauna

Dinosaurs

Ornithischians

Genus Species Material Notes
Dacentrurus D. armatus Skeletal remains.[5] A large stegosaur
Ankylopollexia indet. Indeterminate Femur[6] An ankylopollexian similar to Camptosaurus.
Dracopelta D. zbyweski Fragmentary remains[5] An early ankylosaur
Ornithopoda indet. Indeterminate Footprints[7] 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 Skeletal remains Remains of indeterminate dryosaurids.[8]

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.[2] According to Mateus et al. 2024, a combination of both methods is strong enough to confidently assign teeth on the genus level.[9]

Genus Species Material Notes
Allosaurus[2] A. sp. Teeth
Torvosaurus[2] T. sp. Teeth
Ceratosaurus[2] C. sp. Teeth
Lusovenator L. santosi Articulated caudal vertebrae[10] A carcharodontosaurian.

Sauropods

Genus Species Material Notes
Lusotitan L. atalaiensis Caudal vertebrae[11][5] A brachiosaurid. Freixial material originally regarded by Mannion and colleagues as indeterminate.[12] However Mocho and colleagues noticed depressions on the front of the posterior caudal vertebrate of the Freixial specimen,a diagnostic trait of Lusotitan.[11][13] Thus the Freixial material is referrable to Lusotitan.
Diplodocinae indet. Indeterminate Variety of material[5][14] Various remains of indeterminate diplodocine, including a large (150 cm (59 in)) femur
Camarasauridae indet. Indeterminate Neural spine and partial skeletons[5] Remains of indeterminate camarasaurids
Turiasauria indet. Indeterminate Teeth[5] Teeth attributed to Indeterminate turiasaurians

Mammalia

Genus Species Material Notes
Cambelodon C. torreensis Cranial material A multituberculate[1]

References

  1. ^ a b c 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. ^ a b c d e 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. ^ a b c d e f 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.
  9. ^ 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.
  10. ^ 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.
  11. ^ a b 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.
  12. ^ 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.
  13. ^ 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.
  14. ^ 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)
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