It is endemic to the Palawan Island, the Philippines, and only known from its type locality, Mount Balabag,[4] in the Mantalingajan mountain range.

[2][3] The type series of Alcalus mariae consists of two males measuring 32 and 33 mm (1.3 and 1.3 in) in snout–vent length.

They are stocky frogs with depressed, broad head and rounded snout.

Tips of digits are expanded into large, round disks.

Habitat loss is the most important threat to this species, although the area of type locality is generally well protected.