I grow and hybridize a LOT of Philodendrons in the group where your plant belongs (the Meconostigmas) and I have found that IDing them is difficult if they are grown indoors because the leaf shapes and petioles do not look the same as they do when grown outdoors. To add to the confusion, P. bipinnatifidum is highly variable and may be a complex of hybrids with leaf shapes varying from very deeply divided to mildly divided. A definitive ID in this case requires a study of the blooms.
As for P. x evansii (which is a known hybrid of P. speciosum and P. bipinnatifidum), the mature outdoor leaves on that plant are much larger than yours and longer relative to the width of the leaf. The plant also has some pinkish coloration on the sheath that surrounds the unemerged leaf. Yours does not have the pinkish coloration so to me that would rule out P. x evansii.
LariAnn Garner
Aroidia Research
http://aroidiaresearch.org
