Dryosauridae was a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of primitive
iguanodont
Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivore, herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and rel ...
s, first proposed by Milner & Norman in 1984. They are known from
Middle Jurassic
The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...
to
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
rocks of Africa, Europe, and North America.
Dryosauridae was first proposed in
1984
Events
January
* January 1 – The Bornean Sultanate of Brunei gains full independence from the United Kingdom, having become a British protectorate in 1888.
* January 7 – Brunei becomes the sixth member of the Association of Southeas ...
by British paleontologists Andrew R. Milner and
David B. Norman, as a family to unite the early
ornithopods
Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivore, herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and rel ...
''
Dryosaurus'', ''
Valdosaurus'', and possibly ''
Parksosaurus
''Parksosaurus'' (meaning "William Parks (paleontologist), William Parks's lizard") is a genus of neornithischian dinosaur from the Maastrichtian, early Maastrichtian-age Upper Cretaceous Horseshoe Canyon Formation of Alberta, Canada. It is based ...
'' and ''
Mochlodon''. Milner and Norman separated these taxa from the family
Hypsilophodontidae
Hypsilophodontidae (or Hypsilophodontia) is a traditionally used family (biology), family of ornithopod dinosaurs, generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, ...
as they showed greater similarity with
hadrosaurid
Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...
s and
iguanodontids.
The spelling had previously been used as a typographical error by Deraniyagala in 1939 for
Dyrosauridae.
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.
Iguanodon bernissartensis
''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species found worldwide have been classified in the genus ''Iguanodon'', dating from the Late Jurassic to Early Cretaceous, Taxonomy (bi ...
''." The cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
below follows their chosen reference phylogeny, taken from the description of '' Orthomerus dolloi''.
References
{{Taxonbar, from=Q2505300
Dryosauridae
Dinosaur families