Clade Explorer

Navigate the dinosaur family tree

Interactive phylogenetic tree showing major dinosaur clades from Dinosauria down to genus level. Explore how groups like theropods, sauropods, and ornithischians are related.

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Dinosauria

Sir Richard Owen, 1842 — "Terrible Lizards"

All dinosaurs belong to the clade Dinosauria, which splits into two major orders based on hip structure: Saurischia ("lizard-hipped") and Ornithischia ("bird-hipped"). Ironically, birds evolved from the lizard-hipped branch.

How to Read

Click on any clade to expand its sub-groups and see example species. The tree shows the major divisions from Dinosauria down to family level. Names in quotes show the etymology (Greek/Latin meaning).

How to Use

  1. 1
    Open the phylogenetic tree

    The tree loads at the Dinosauria node, divided into the two primary clades Saurischia and Ornithischia. Click any node to expand it and reveal the subordinate taxa below.

  2. 2
    Navigate to a taxon of interest

    Use the search bar to jump directly to any family, genus, or species. The tree will expand and highlight the path from Dinosauria down to your target, showing all intermediate nodes.

  3. 3
    Compare sister groups

    Select any two terminal or internal nodes to open a comparison panel showing diagnostic characters, temporal ranges, and geographic distributions that distinguish the two groups.

About

Phylogenetics is the scientific discipline that reconstructs the evolutionary history of organisms by analysing shared inherited characters. For dinosaurs, the foundational work by Jacques Gauthier in 1986 established the cladistic framework that all subsequent research builds on, placing birds firmly within theropod dinosaurs and clarifying the relationships among major groups. The two-part division into Saurischia and Ornithischia, first proposed by Harry Seeley in 1887, remains the standard framework, although a 2017 analysis by Matthew Baron and colleagues proposed a radical rearrangement that has been both supported and challenged by subsequent studies.

Phylogenetic trees are hypotheses, not facts, and they change as new specimens are described and as analytical methods improve. Large datasets with hundreds of taxa and thousands of characters now allow statistically robust tests of relationships that would have been impossible with earlier methods. Bayesian inference methods, which incorporate information about evolutionary rates and stratigraphic age, are increasingly used alongside parsimony analysis to produce time-calibrated trees.

Understanding phylogeny matters for interpreting almost every other aspect of dinosaur biology. Reconstructing soft tissue anatomy, physiology, behaviour, and ecology in extinct taxa depends on identifying the closest living relatives from which functional comparisons can be drawn. The clade explorer on DinoFYI provides a navigable version of the current scientific consensus, with nodes annotated by the diagnostic characters and key references that underpin each grouping.

FAQ

What is the difference between Saurischia and Ornithischia?
Saurischia and Ornithischia are the two primary divisions of Dinosauria, distinguished principally by hip anatomy. Saurischians have a lizard-like pelvis in which the pubis points forward and downward, while ornithischians have a bird-like pelvis in which the pubis is rotated backward. Paradoxically, modern birds are saurischians, not ornithischians. Saurischia includes all theropods and sauropodomorphs; Ornithischia includes ornithopods, ceratopsians, stegosaurs, and ankylosaurs.
What does a phylogenetic tree actually represent?
A phylogenetic tree is a hypothesis about the evolutionary relationships among organisms, expressed as a branching diagram. Each internal node represents a hypothetical common ancestor; each branch represents a lineage. Trees are constructed by analysing shared derived characters — features present in the descendants of a common ancestor but absent in outgroups. In palaeontology, these characters are typically skeletal features scored from specimen photographs, CT scans, and first-hand examination.
Are birds considered dinosaurs?
Yes, under the phylogenetic definition used in modern systematics. Birds are a clade of maniraptoran theropods, nested within Dinosauria. The evidence is overwhelming: birds share over 100 skeletal characters with non-avian theropods, Jurassic fossils like Archaeopteryx are transitional in morphology, and feathers are now known from dozens of non-avian theropod species. The term "non-avian dinosaurs" is used to refer to the extinct forms, while birds are the surviving avian branch.
How are new dinosaur species placed on the tree?
New species are placed using cladistic analysis: a matrix of anatomical characters is scored for the new taxon and for a broad sample of related species, and a computer algorithm finds the tree topology requiring the fewest evolutionary changes (the most parsimonious tree). Multiple analyses often produce slightly different topologies, reflecting genuine uncertainty. The position of a taxon on the DinoFYI tree reflects the consensus or most recent comprehensive analysis available in the primary literature.
What is a ghost lineage and how is it shown on the tree?
A ghost lineage is a portion of a clade's evolutionary history that is phylogenetically inferred but currently has no fossil record. If two sister lineages diverge at time A but one is only known from time B, the clade must have existed from A to B even if no fossils from that interval have been found. Ghost lineages indicate gaps in the fossil record rather than gaps in evolution. The clade explorer shows known fossil ranges as solid lines and inferred ghost lineages as dashed extensions.