Monstera adansonii is similar to Monstera obliqua but Monstera obliqua and Monstera adansonii are not the same species. There are many hybrids in cultivation between Monstera adansonii and Monstera obliqua.
Monstera obliqua leaves are as thin as a sheet of paper, when adansonii leaves are a bit rough. Obliquas leaves consist mostly of holes. Adansonii leaves are not as longitindial as obliqua's. The holes in adansonii cover generally half of the adult leaf.
See Article about Philodendrons.