The genus Metapocyrtus Heller, 1912, is the most speciose and taxonomically complex genus in the tribe Pachyrhynchini. Currently, the genus is comprised of more than 250 species that are classified into seven subgenera. One of the least studied subgenera under the genus Metapocyrtus is the subgenus Dolichocephalocyrtus Schultze, 1925, whose members are generally known for their long and slender rostrum (0.60 to 0.76 times as long as wide). Another distinct feature of this subgenus is the evident sexual dimorphism: males possess elytra with a rounded apex and a steep apical declivity, while females exhibit a sharply pointed, triangular projection at the elytral apex. Like most weevils under the genus Metapocyrtus, species under the subgenus Dolichocephalocyrtus have a narrow geographic range due to their flight inability; this is probably the reason why all known species under this subgenus are endemic to the Philippines.

A new species of flightless weevil, belonging to the genus Metapocyrtus Heller, 1912, subgenus Dolichocephalocyrtus Schultze, 1925, from the Aliwagwag Protected Landscape (APL), Cateel, Davao Oriental, Mindanao, Philippines, is described and illustrated. Named after the Aliwagwag Falls, the novel species, Metapocyrtus (Dolichocephalocyrtus) aliwagwag Pajota & Cabras, sp. nov., is the first species of the genus to be formally described from Cateel, Davao Oriental. The description of this novel species adds to the rich diversity of the genus Metapocyrtus in the country and highlights the ecological significance of the Eastern Mindanao Biodiversity Corridor (EMBC).