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Eousdryosaurus

Escaso et al., 2014 yuss-dry-o-sor-us

From Greek eous (eastern) + Dryosaurus (the related genus): 'eastern Dryosaurus', referring to its geographic origin in Portugal relative to other dryosaurid relatives.

154.8–143.1 million years ago Kimmeridgian–Tithonian, Late Jurassic
Late Jurassic stages

Eousdryosaurus is a genus of basal iguanodontian dinosaur known from a partial skeleton discovered in Upper Jurassic rocks in western Portugal. The type, and only species, is Eousdryosaurus nanohallucis, named and described in 2014.

Diagnosis

  1. Proximal-most caudal neural spines with a small thorn-like anterior process
  2. Extremely wide ilium brevis shelf that is ventromedially directed
  3. Astragalus with a prominent triangular posteromedial process that obscures the anterior surface
  4. Calcaneum with a strong proximal projection that has a rounded dorsal margin
  5. Medial distal tarsal composed of sutured but not fused distal tarsals 1 and 2
  6. Metatarsal V with a blunt eminence at midshaft that breaks in slope to its distal end
  7. Phalangeal formula for the pes of 1-3-4-5-0, with ungual of digit I uniquely extremely reduced, dorsoventrally flattened, elongated and pointed

Species

Eousdryosaurus nanohallucis Escaso et al., 2014

Type species

From Greek 'nanos' meaning 'small' and Latin 'hallux' meaning 'big toe', referring to the unusually small first digit of the foot.

Holotype
SHN(JJS)-170 , Sociedade de Historia Natural
Material
Partial skeleton: nine articulated proximal caudal vertebrae; left ilium; right femur; proximal left femur; left tibia; left fibula; left astragalus; left calcaneum; left distal tarsals; complete left pes
Horizon
Praia da Amoreira-Porto Novo Member, Lourinhã Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
Locality
Porto das Barcas, Lisbon, Portugal

References

  1. Escaso, F.; Ortega, F.; Dantas, P.; Malafaia, E.; Silva, B.; Gasulla, J. M.; Mocho, P.; Narváez, I.; Sanz, J. L. (2014). A new dryosaurid ornithopod (Dinosauria, Ornithischia) from the Late Jurassic of Portugal. Journal of Vertebrate Paleontology 34(5): 1102-1112. Informa UK Limited. doi:10.1080/02724634.2014.849715 escaso2014a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the mass and hip height estimates.

    jones2026a
  3. Mateus, O.; Dinis, J.; Cunha, P. P. (2017). The Lourinhã Formation: the Upper Jurassic to lowermost Cretaceous of the Lusitanian Basin, Portugal - landscapes where dinosaurs walked. Ciências da Terra - Earth Sciences Journal 19(1): 75-97. doi:10.21695/cterra/esj.v19i1.355

    Maps the Alcobaça Formation of the describing paper onto the Lourinhã Formation's member scheme, in which this horizon is the Amoreira-Porto Novo Member.

    mateus2017a