The genus Kaloula is part of a large group of narrow mouth frogs in the family Microhylidae. The approximately 65 genera of narrow mouth frogs occur in North and South America, Africa, Australia, and Souteast Asia. Of the ten subfamilies, the genus Kaloula is a member of the Microhylinae group.
Within the Philippines, the diversity of species in the genus Kaloula can be roughly broken down into three major ecomorphological groups. The first being the shrub frogs. This group consists of species historically believed to all be subspecies of Kaloula conjuncta. They have expanded toe disks used for an arboreal lifestyle. During the rainy season they will climb down and breed in ephemeral pools of water on the ground. Tadpoles within this group are pigmented. The group of shrub frogs has a large distribution throughout the Philippines. There are clear divisions between species with true K. conjuncta occurring throughout Luzon, K. negrosensis observed throughout the visayan islands, K. meridionalis observed in mindanao, and the type locality of K. stickelii occurring on samar.
The second group consists of burrowing frogs with narrow toe disks. These frogs burrow during the year except for the rainy season, when they surface and breed in pools on the ground. Tadpoles of this group also are pigmented. With the exception of Kaloula picta, which has dispersed throughout the Philippines, the other burrowing frogs have narrow ranges. Kaloula rigida occurs in North Luzon and Kaloula walteri occurs in Southern Luzon and Polillo Island. Kaloula pulchra has been recently introduced into the Philippines, and has now been observed at several localities on Luzon Island (Siler et al., 2011) in the northern Philippines.
The third group of species in the genus Kaloula have evolved a completely arboreal lifestyle. They spend their lives within tree-holes, have wide toe disks, and non-pigmented tadpoles (likely due to an absence of contact with the sun). The tadpoles complete their lifecycle within the tree hole itself. These frogs are recognized to possess restricted ranges, possibly due to their dependence on primary forest habitat. Two different species of tree hole frogs occur on Luzon. Kaloula kalingensis is restricted to the north, a new species spanning across central Luzon, and K. kokacii is recognized to occur in southeastern Luzon Island and on Catanduanes Island.
Author: Siler, Cameron
reported as Manila, the capital city of the Philippines on Luzon Island; type reported to be in the Museum National d'Histoire Naturelle, Paris; MNHNP 5027
Author: Siler, Cameron