Dinosaurs

Just chocked full of flavour.

Dinosaurs are prehistoric reptiles that in the past dominated the worlds landmasses. It was belevied for many years they had all become extinct 65 million years ago, although this idea was revived at certain points

While real dinosaurs do appear in Transformers, their most prominent roles where as the alt modes for some of the most dangerous, and occasionally ludicrous, transformers of all time.

Fiction

Generation 1 animated continuity

The last thing you want to see down a dark alley

Dinosaurs survived the mass extinction of 65 million years ago and lived on into the present on the time displaced, and energy rich Dinobot Island.

The most prominent saurians in G1 were the Dinobots five rebellious, yet extremeely powerful autobots proved time and again a match for an amry of decepticons. Other dinosaur transformers were Trypticon, Sly Lynx (G1) and the cassettetes, Slugfest and Overkill

Marvel G1 Continuity

Dinosaurs survived in a part of the Antarctic known as the Savage Land

Victory

The Dinoforce consisted of 6 Decepticons with sentient dinosaur pretender shells and the ability to combine into Dinoking

Beast Wars

You dare call me Barney!!!!!!!!

Beast Wars featured two prominent dinosaur transformers, Dinobot (BW) who was either a giant Velociraptor or an average sized Utharaptor, and Megatron (BW) who's orignal and transmetal alt modes weere that of a dwarf Tyrannosaurus.

Terrorsaur transfomred inot a Pteranodon, a creature frequently mistaken for a dinosaur.

Beast Wars II

Brother, I think my horn has a rash

Gigastorm, Galvatron (BWII)'s younger brother, took the form of a therapod dinosaur

Beast Wars Neo

The Predacon line up consisted of a number of dinosaurs, including Magmatron, Guiledart, Hardhead (BWN) and Saberback

Cybertron

He acts tough but keeps disappearing when Grimlock turns up in a room.

One of Scourge's underlings, Undermine transformes into a Spinosaurus.

Animated

Grimlock and slag will be dinosaurs(T-Rex and Triceratops) while Swoop will be a peterosaur.

From Teletraan I: The Transformers Wiki, a Wikia wiki.