Dryosauridae
Dryosauridae is a family of small, gracile, bipedal ornithopod dinosaurs known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America. Its members include Dryosaurus, Dysalotosaurus, Valdosaurus, Elrhazosaurus, and Callovosaurus, several of which were once dismissed as dubious or as species of Dryosaurus before later studies re-established them as valid. These were lightly built, long-legged herbivores adapted for running, and were originally set apart from the hypsilophodonts because they more closely resembled the larger iguanodontians and hadrosaurs. They lacked the specialized thumb spike of their more advanced relatives and sit as an early branch just outside the ankylopollexian ornithopods.
Diagnosis
- Edentulous, beak-like premaxilla
- Long, slender hindlimbs with an elongate tibia relative to the femur
- Absence of a manual pollex spike
- Crownward ridge pattern with a single strong primary ridge on dentary teeth
Genera placed directly in Dryosauridae
- Callovosaurus Callovian (165.3–161.5 Ma)United Kingdomunder dispute
- Dryosaurus Kimmeridgian–Tithonian (154.8–143.1 Ma)United States
- Dysalotosaurus Kimmeridgian (154.8–149.2 Ma)Tanzania
- Elrhazosaurus Aptian (121.4–113.2 Ma)Niger
- Eousdryosaurus Kimmeridgian–Tithonian (154.8–143.1 Ma)Portugal
- Iyuku Valanginian (137.1–132.6 Ma)South Africa
- Valdosaurus Barremian (125.8–121.4 Ma)United Kingdom
References
-
Milner, A. R.; Norman, D. B. (1984). The biogeography of advanced ornithopod dinosaurs (Archosauria: Ornithischia) — a cladistic-vicariance model. Third Symposium on Mesozoic Terrestrial Ecosystems, Short Papers 145-150. Attempto Verlag.
Named Dryosauridae.
milner1984a -
Madzia, D.; Arbour, V. M.; Boyd, C. A.; Farke, A. A.; Cruzado-Caballero, P.; Evans, D. C. (2021). The phylogenetic nomenclature of ornithischian dinosaurs. PeerJ 9: e12362. doi:10.7717/peerj.12362
Provides the modern phylogenetic definition of Dryosauridae.
madzia2021a