from the earlier thread, it was coined by...
Christopher Morley, in the preface to "The Complete Sherlock Holmes" [of Conan Doyle]:
"What other man led a fuller and heartier and more masculine life? [it was another age]
Doctor, whaler, athlete, writer, speculator, dramatist, historian, war correspondent,
spiritualist, he was always also the infracaninophile -- the helper of the underdog."
not all dictionaries are on the web just yet, nor do I have all dictionaries in hard copy (it only seems that way), but I do have it in print in two actual books: as quoted above and in Charles Harrington Elster's "There's a Word for it!" perhaps Mrs. Byrne has it in her dictionary also, but I don't have that to hand at the moment.
(it seems highly probable that Morley coined this as a nonce-word, but there is still time to get it into the OED if only enough of us get... on top of it.)
EDIT: Mrs. B. indeed covers the word, but she cites Morley for it, indicating that she also found it in none of her lexicographical references. :)
