Myfanwy

Myfanwy is a pteranodon kept by Torchwood 3 as a pet.

History
The pteranodon was caught in the Cardiff rift and brought into 21st century Cardiff.


 * Jack implied that it originated, not from the distant past of planet Earth, but from an alternative timeline in which its kind had never gone extinct. (TW: Meat)

It was originally found hunting in the countryside, killing sheep at night. (TW: Everything Changes) Eventually, Ianto Jones was able to trap it in a warehouse and was able to persuade Jack Harkness to help him catch it. (TW: Fragments) It is presumably Ianto, a Welshman, who named the pteranodon "Myfanwy", after a Welsh mythological figure famed for her sweet singing.

Jack Harkness was later able to use the pteranodon to attack Lisa Hallett, mortally injuring her. (TW: Cyberwoman) The pteranodon, on the other hand, survived the encounter. (TW: Meat)

Personality
The Torchwood Pteranodon came and went from the main base as it pleased, entering through a large opening on the ceiling. It was well trained, being called by a signal from Jack Harkness's wristwatch and only eating food with a certain "barbecue sauce" on it, which Suzie Costello had developed. (torchwood.org.uk, TW: Cyberwoman) The pteranodon also had a fondness for dark chocolate. (TW: Fragments)

Behind the Scenes
The in-universe Torchwood website refers to the creature as a pterodactyl, rather than a pteranodon. Torchwood Declassified mentions that the pteranodon was nicknamed Myfanwy by the cast. This is later shown to be the case in-univere, when we read an IM conversation between Ianto and Owen about Myfanwy's feeding habits (torchwood.org.uk).

Technically, it has appeared in every Torchwood episode so far, as a clip of it appears in the series' opening credits.