Monstera membranacea is a stunning aroid that possesses intricate bullate leaves, ruffled edges and dramatic maturing fenestration. They are remarkably similar in fenestration to Amydrium medium, and often considered a spectacular example of convergent evolution in aroids. In the wild, this plant ranges from Costa Rica to Panama. This locality originates from Uvita in the Southern Pacific lowlands of Costa Rica, and differs visually from the Caribbean Limón form. Attached below are images of both these forms in their juvenile & adolescent stages, respectfully.
Below: Juvenile foliage of both forms
Below: adolescent/maturing forms
Below is the growth progress of my Southern Pacific lowland ecotype Monstera membranacea