aristolochioides X spectabilis
I am still firmly of the opinion that plant is cultivar-worthy....I have never seen another Nepenthes, let alone N. naga, getting as dark as yours....
Ummm...sibuyanensis x 'Lady Pauline'? That's the best I've got...
Nepenthes villosa by _Heli, on Flickr
Nepenthes villosa by _Heli, on Flickr
Nepenthes hamata by _Heli, on Flickr
Nepenthes argentii by _Heli, on Flickr
Nepenthes lingulata by _Heli, on Flickr
Nepenthes edwardsiana (Tambuyukon) by _Heli, on Flickr
Nepenthes spectabilis (Pangulubao) by _Heli, on Flickr
Nepenthes stenophylla by _Heli, on Flickr
Nepenthes macfarlanei by _Heli, on Flickr
Nepenthes faizaliana by _Heli, on Flickr
Nepenthes x kinabaluensis (Gunung Kinabalu) by _Heli, on Flickr
Nepenthes macrophylla by _Heli, on Flickr
Nepenthes macrophylla by _Heli, on Flickr
Untitled by _Heli, on Flickr
Untitled by _Heli, on Flickr
Untitled by _Heli, on Flickr
Untitled by _Heli, on Flickr
Untitled by _Heli, on Flickr
Untitled by _Heli, on Flickr