Dryosauridae

Not to be confused with Dyrosauridae.

Dryosauridae was a family of primitive iguanodonts, first proposed by Milner & Norman in 1984. They are known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America.^[2][3][4][5]

Dryosauridae Temporal range: Middle Jurassic – Early Cretaceous, 164–115 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Dysalotosaurus skeletal mount in Berlin
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Ornithopoda
Clade:	†Iguanodontia
Clade:	†Dryomorpha
Family:	†Dryosauridae Milner & Norman, 1984[1]
Subgroups
†Callovosaurus? †Dryosaurus †Dysalotosaurus †Elrhazosaurus †Eousdryosaurus? †Iyuku? †Kangnasaurus? †Valdosaurus †Vectidromeus?

Dryosauridae was first proposed in 1984 by British paleontologists Andrew R. Milner and David B. Norman, as a family to unite the early ornithopods Dryosaurus, Valdosaurus, and possibly Parksosaurus and Mochlodon. Milner and Norman separated these taxa from the family Hypsilophodontidae as they showed greater similarity with hadrosaurids and iguanodontids.^[1] The spelling had previously been used as a typographical error by Deraniyagala in 1939 for Dyrosauridae.^[6]

Classification

Until recently, many dryosaurids have been regarded as dubious (Callovosaurus and Kangnasaurus) or as species of the type member, Dryosaurus (Dysalotosaurus, Elrhazosaurus and Valdosaurus). However, more recent studies redescribe these genera as valid.^{[4][5][7][8][9]} Under the Phylocode, Madzia et al. (2021) formally defined Dryosauridae as "the largest clade containing Dryosaurus altus but not Iguanodon bernissartensis."^[10] The cladogram below follows their chosen reference phylogeny, taken from the description of Orthomerus dolloi.^[11]

Iguanodontia	Rhabdodontidae Rhabdodon spp. Zalmoxes robustus Mochlodon vorosi Zalmoxes shqiperorum Tenontosaurus tilletti Tenontosaurus dossi Dryomorpha Ankylopollexia Dryosauridae Eousdryosaurus nanohallucis "Camptosaurus" valdensis Callovosaurus leedsi Dysalotosaurus lettowvorbecki Dryosaurus altus Valdosaurus canaliculatus Elrhazosaurus nigeriensis