Dinosaur catalogue A to Z

Species, genera and familiar dinosaur names

Most familiar names, including Tyrannosaurus, Triceratops and Diplodocus, identify a genus rather than one biological species. A genus may contain one accepted species or several. Tyrannosaurus is a genus, while Tyrannosaurus rex is a species; Triceratops is a genus, while Triceratops horridus is one species within it.

People commonly search for “types of dinosaurs”, so this catalogue retains that familiar wording while every profile states whether the subject is a genus, species or larger group. A physical museum specimen is different again: one named species may be represented by a single partial skeleton or by hundreds of individuals. The guide to species, genera, families and clades explains these levels in detail.

How to use the catalogue

Search by common name, scientific name, group or a distinctive feature. The filters narrow the cards by geological period, diet, broad evolutionary group and approximate length. They are navigation aids, not substitutes for the evidence in each profile. A doubtful name can still appear in the catalogue when its history is scientifically useful, but the profile labels that uncertainty directly.

Length categories use cautious ranges from the profiles. Complete skeletons are rare, individuals grew through different body sizes and missing bones are often restored from relatives. A filter therefore places an animal in a practical comparison band rather than declaring a perfectly measured maximum.

The main dinosaur groups

These are nested evolutionary branches, not equal boxes based only on appearance. The deepest split among the major lineages remains debated, although the membership of many later families is stable. The dinosaur classification guide shows how a cladogram records common ancestry.

Animals that are not dinosaurs

Pteranodon and pterodactyls were pterosaurs. Ichthyosaurs, plesiosaurs, pliosaurs and mosasaurs were marine reptiles. Dimetrodon was an early synapsid, mammoths were mammals and megalodon was a shark. Some lived before dinosaurs, some alongside them and others much later, but they belonged to different evolutionary lineages.

How palaeontologists determine relationships

Classification is not built from size, diet or a general resemblance. Researchers compare many anatomical characters in the skull, teeth, vertebrae, pelvis, limbs, ankle and body coverings, then test how those characters are distributed across possible evolutionary trees. Age and geography provide context but do not override anatomy.

A new skeleton can move a genus to another branch, show that two old names refer to the same animal or demonstrate that one historical genus combined unrelated material. That is why names such as “prosauropods”, “thecodonts” or a single broad genus Troodon have been revised. The fossil has not changed; the hypothesis that best explains it has.

Why size estimates differ

1. A skeleton may be incomplete or distorted.
2. Different specimens may represent juveniles, mature adults or unusually large individuals.
3. Missing bones are reconstructed from relatives with imperfectly known proportions.
4. Historical material may later be assigned to another genus.
5. Straight-line length and length measured along a curved vertebral column are not identical.
6. Popular summaries often repeat the largest estimate without its assumptions.

A defensible range is usually more informative than one dramatic number. The interactive dinosaur size comparison keeps length and mass separate and shows why both estimates carry uncertainty.