I would also like to share an interesting story that I found on the University of British Colombia's Botanical website about it's rarity and provenance:
"Philodendron 'joepii' (pronounced yupe-E-eye) is indeed rare and I was very surprised at the final price on eBay. The sought after and very odd Philodendron with it's wide lower lobe tapering up wards into a slender narrow upper body and then topped by a pair of upwardly and outwardly pointing lobes was found by Joep Moonen in 1991 on the Mataroni River in eastern French Guiana. Only two natural specimens are known to exist in nature.
The plant was seemingly so malformed Joep (yupe) first thought it had simply been eaten by insects but when he returned to the site he found it normally grew in that form. That plant existed on an ant's nest! When he attempted to recover an ant covered specimen he fell into the boat and thousands of ants over whelmed both he and the boat! Joep was certain he would be eaten alive! To save both himself and the plant Joep elected to tow the specimen behind the boat for an hour to get rid of all those ants! Unsure if he had actually found a new species Joep began labeling each new leaf with the date it was collected. He has subsequently found only one additional plant on the river so only two specimens have ever been seen!
The plant is extremely rare and it's leaves grow to approximately 70 cm (27 1/2 inches) in length. This plant is still under scientific investigation and has not been officially scientifically identified. Joep has come to the conclusion it may be a hybrid and made this comment in a personal email exchange while we were discussing another somewhat similar plant found at the gardens of Roberto Burle-Marx in Brazil saying it may be "a natural hybrid between Philodendron bipennifolium and Philodendron pedatum. The 'ears' and inflorescences of 'joepii' look like (those) in pedatum." Commenting that both of these species grew near the natural locations of P. 'joepii' he went on to explain, "I found only 2 plants in the wild (on the) Mataroni River in eastern French Guiana, many Amazonian species there". In February, 2008 Philodendron 'joepii' bloomed for Joep for the very first time. But please understand, an inflorescence is not a "flower". It is a group of flowers, both male and female. The actual spathe is nothing more than a modified leaf. Production of a spathe and spadix is quite rare on this specimen."