These are simply notes to myself about taxonomic classifications in Wikidata. Classifications in Wikidata can be complex and are often not trees. For example, if we trace the parents of the frog family Leptodactylidae back we get a graph like this: Each oval represents a taxon in Wikidata, and each arrow connects a taxon to its parent(s) in Wikidata.

Rutger Vos asked on Twitter "What would people want/expect from taxon searching on TreeBASE?". This is a good question, and one which motivated the work I did on TBMap (see doi:10.1186/1471-2105-8-158), which developed a mapping between TreeBASE taxa and other databases. In that paper I published a table showing the effectiveness of string and hierarchical queries of TreeBASE.