Draconian

Draconians were a race of reptilian humanoids from Draconia.

Biology
The Draconians were a tall, reptilian species. (DW: Frontier in Space)

Culture
The Draconians were ruled by an Emperor, who depended on the great families for support. (DW: Frontier in Space) They were a highly formal race and were known for their adherence to rules and traditions. They believed that rules were made to be followed and would stick to them no matter what. Draconians also had a great respect for authority. (MA: The Dark Path) Though they were originally male-dominated, (DW: Frontier in Space) after their entrance to the Galactic Federation they later changed their ways in order to show equality (MA: The Dark Path). They also believed that men should not show sadness or cry. (MA: The Dark Path)

Mr. Smith told Luke Smith that Draconia was one of many worlds in the universe which had developed a form of astrology (SJA: Secrets of the Stars). However, another source alleged that the race commonly known as Draconians had no form of astrology (MA: The Dark Path).

The Draconians, like other species in the universe, had a horned god of evil, which the Doctor believed to be the Beast. (DW: The Satan Pit)

History
In the year 1645, an outbreak of Skreeths was discovered and the Time Lords dispatched the Doctor to enlist allies to stop the infection. After informing the Draconians, they decided to adopt a "scorched galaxy" policy which involved obliterating any worlds that developed signs of infection. This was something that the Doctor later regretted after the chain of events though he later managed to end the infection from spreading. (ST: The Devil Like a Bear)

During the reign of the fifteenth Emperor (at some point during the 21st century), Draconia was suffering from a plague. The Doctor came to the planet and cured the plague. He was remembered as the form of a painting in the Emperor Palace. (MA: The Dark Path)

Humans and Draconians were aware of each other by the end of the 25th century and coexisted peacefully. (NSA: Judgement of the Judoon)

However, by the 26th century, the expanding Draconian Empire came into contact with the Earth Empire. A misunderstanding during first contact led to the destruction of a Draconian vessel and a brief but devastating war, which ended with the signing of a peace treaty.

Twenty years later, the Master attempted to sabotage the fragile peace, but was thwarted by the Doctor and Jo Grant. (DW: Frontier in Space)

A Draconian ship was flying to an outpost when it crashed on Earth. (DWM: War-Game)

The Doctor, Jason and Crystal visited the 'Bar Galactica' in their search for a missing US Peace Envoy. Among the Bar's customers there was a Draconian. (SP: Doctor Who: The Ultimate Adventure)

Series 5
The Draconians are rumoured to return in Series 5