Have you ever wondered where a dinosaur gets its name from? Why is it called T. rex sometimes, and Tyrannosaurus rex other times? This week, a little crash course on what we call taxonomy, specifically, the Linnaean taxonomic system, which is what biologists (and palaeontologists) use today.
To start, a basic lesson on the different groups that we classify animals into. It's a hierarchical system, with all animals being grouped from the top (Kingdom) to the bottom (Species) with the classification as follows:
All animals belong to the Kingdom Animalia, while according to some classifications, dinosaurs are in the Order Dinosauria, and pterosaurs are Order Pterosauria. All dinosaurs are further grouped into families like the Hadrosauridae (duck-billed dinosaurs), Ceratopsidae (horned dinosaurs) and Tyrannosauridae (tyrannosaurs). Families are distinguished by ending in -idae, and in common language, -id (e.g. a hadrosaurid). According to the Linnaean classification system (named for Carl Linnaeus, who invented the system in 1735), the scientific names from Kingdom to Genus should be capitalised when the full name is used. Genus (genera plural) names should be capitalised AND italicised when in print, while species names should always be in lower case and italicised.
Now the genus name is usually what we use to identify dinosaurs. Genus names are used to describe the dinosaur as well, usually with a descriptive feature, or where it was found, or sometimes named after someone, in either Latin or Greek primarily. A species name is used to describe that specific species. There can be many species in one genus, and species are defined by a group of animals that cannot interbreed with other animals to make fertile offspring. In palaeontology, this is difficult because we can't tell from fossils if animals were capable of interbreeding. We make assumptions based on how the animals look.
As mentioned before, genus names are usually what we use to identify fossils like dinosaurs and pterosaurs. A perfect example of that is Tyrannosaurus. The genus is Tyrannosaurus, while the entire species is called Tyrannosaurus rex, which can be shortened to T. rex. Tyrannosaurus means 'tyrant-lizard' while rex is Latin for king, making it the 'tyrant-lizard king'. Genera that describe certain features about the dinosaur include Dilophosaurus (two-crested lizard), and Centrosaurus (pointed lizard), while others are named for people (e.g. Lambeosaurus for Canadian palaeontologist Lawrence Lambe) or where they are found (e.g. Albertosaurus for Alberta).
All modern animals have scientific names with genus and species, in addition to their common names. Humans are Homo sapiens, the lynx is Lynx canadensis, and the moose is Alces alces.