Dryosaurids were primitive

iguanodont Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', '' Tenontosaurus'', and the hadrosaurids or "duck-bil ...

s. They are known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America.

Phylogeny

Until recently many dryosaurids have been regarded as

dubious Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to be certain of any of them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty ...

('' Callovosaurus'' and '' Kangnasaurus'') or as species of the type member, ''

Dryosaurus ''Dryosaurus'' ( , meaning 'tree lizard', Greek ' () meaning 'tree, oak' and () meaning 'lizard'; the name reflects the forested habitat, not a vague oak-leaf shape of its cheek teeth as is sometimes assumed) is a genus of an ornithopod dinosaur ...

'' (''

Dysalotosaurus ''Dysalotosaurus'' ("uncatchable lizard") is a genus of herbivorous iguanodontian dinosaur. It was a dryosaurid iguanodontian, and its fossils have been found in late Kimmeridgian-age rocks (Late Jurassic) of the Tendaguru Formation of Lindi Regi ...

'', '' Elrhazosaurus'' and ''

Valdosaurus ''Valdosaurus'' ("Weald Lizard") is a genus of bipedal herbivorous iguanodont ornithopod dinosaur found on the Isle of Wight and elsewhere in England, Spain and possibly also Romania. It lived during the Early Cretaceous. Discovery and naming ...

''). However, more recent studies redescribe these genera as valid. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

below follows Paul M. Barrett, Richard J. Butler, Richard J. Twitchett and Stephen Hutt (2011).

References

{{Taxonbar, from=Q2505300 Iguanodonts Middle Jurassic first appearances Cretaceous extinctions Prehistoric dinosaur families Taxa named by Angela Milner Taxa named by David B. Norman