The only animal I had the possibility of finding that starts with an "X" is the African clawed frog Xenopus laevis.
*native to South Africa
*earliest record of chytridiomycosis (1938)
*used in human pregnancy tests (1930s-1970s)
*amphibian ‘lab rat’ (immunology, embryology)
*distributed around the world by 1000s-10,000s/year
I didn't ID the frogs the birds were eating in some of the pics (Hammerkop, Saddle-billed Stork), so I don't know if I have an entry or not here

