Hadrosauroidea is a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

or superfamily of

ornithischia Ornithischia () is an extinct clade of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

s that includes the "duck-billed" dinosaurs, or

Hadrosauridae 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 fam ...

, and all dinosaurs more closely related to them than to ''

Iguanodon ''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 ...

''. Their remains have been recovered in Asia, Europe, Africa and the Americas. Many primitive hadrosauroids, such as the Asian '' Probactrosaurus'' and '' Altirhinus'', have traditionally been included in a

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

(unnatural grouping) " Iguanodontidae". With

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

analysis, the traditional Iguanodontidae has been largely disbanded, and probably includes only ''Iguanodon'' and perhaps its closest relatives.

Classification

Hadrosauroidea was given a formal phylogenetic definition in the ''

PhyloCode The ''International Code of Phylogenetic Nomenclature'', known as the ''PhyloCode'' for short, is a formal set of rules governing phylogenetic nomenclature. Its current version is specifically designed to regulate the naming of clades, leaving the ...

'' by Daniel Madzia and colleagues in 2021 as "the largest clade containing '' Hadrosaurus foulkii'', but not '' Iguanodon bernissartensis''". 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 an analysis by Andrew McDonald, 2012, and shows the position of Hadrosauroidea within Styracosterna: The

below follows an analysis by Wu Wenhao and Pascal Godefroit (2012): Cladogram after Prieto-Marquez and Norell (2010): A

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis performed by Ramírez-Velasco ''et al.'' (2012) found a large polytomy between all hadrosauroids that are more derived than '' Probactrosaurus'' but less derived than

. The exclusion of '' Claosaurus'', '' Jeyawati'', '' Levnesovia'', '' Nanyangosaurus'', '' Shuangmiaosaurus'' and '' Telmatosaurus'' from the analysis resulted in a more resolved topology:

References

{{Taxonbar, from=Q1032465 Dinosaur superfamilies Cretaceous dinosaurs

Classification

See also

References