Of course, taxonomy and biosystematics are crucial to this endeavour, from understanding the taxonomy and relationships of the extinct animals to using phylogeny and classification to choose close relatives to edit.
For many years, for example, the relationships of the thylacine were debated. While clearly a marsupial (which means the similarity to dogs is caused by convergent evolution), there were ambiguous results suggesting it may have been closely related to either other Australian marsupials such as quolls and Tasmanian devils, or to an extinct group of South American carnivorous, dog-like marsupial relatives called the borhyaenids.
This paper uses molecular phylogenetic methods to firmly place the thylacine with other Australian carnivorous marsupials. This placement is now strongly supported by numerous studies.