I recently learned about them and find many similarities:
- small winged dragon (around than 2 feet long)
- can be a pet
- (relatively) short lived
- limited ability to communicate
Since D&D has many versions, I face difficulties identifying when pseudodragons were first defined but they seem to be mentioned in a first version (1977).
Digging around this topic, I found the small pet dragon trope: it seems to be even older?
Does anyone have a Terry Pratchett interview or discussion about this topic?